2024 Fall Unit 1 Notes.pptx

Basic Chemistry Sixth Edition Chapter 1 Chemistry in Our Lives Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved The Thinking Process !  The Scientifi...

Basic Chemistry Sixth Edition Chapter 1 Chemistry in Our Lives Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved The Thinking Process !  The Scientific Approach to Knowledge The approach to scientific knowledge is empirical. It is based on observation and experimentation. The scientific method is a process for understanding nature by observing nature and its behavior through experimentation. Key characteristics of the scientific method: Observations Formulation of hypotheses Experimentation Formulation of conclusions and theories  Scientific Method An approach to problem solving Observation Hypothesis Experiments Theory or Conclusion  Observations Observations: noting and recording a natural phenomenon AKA data. The descriptions about the characteristics or behavior of nature. What background information or data do you have? This is your observation Observations can come from studying nature or from experimentation. formulate a hypothesis.  Hypothesis A hypothesis is: a tentative explanation of the facts, based on reason and evidence. unverified (has not been tested). sometimes in the form of an if-then statement. A good hypothesis: is falsifiable. Includes an independent (the one you change) and dependent (the one you measure) variable with some relationship Can be tested with an experiment The results of an experiment may validate or invalidate a hypothesis. When a result does not validate the hypothesis the scientist must modify or discard it.  Lavoisier explained his observations on combustion by hypothesizing that when a substance burns, it combines with a component of air. Independent variable: Dependent variable: Relationship:  Experiments Procedure that tests the validity of a hypothesis and creates more data or observations How can you check? This is the experiment (how you interact with the subject) When I do that, this happens. Determines the relationship between hypothesis and observation Valid Invalid  Theory/Conclusion A well-established hypothesis or set of hypotheses form the basis for a scientific theory. A theory tries to explain not merely what nature does, but why a natural phenomenon happens. Characteristics and behavior of nature Examples: Dalton’s atomic theory Big Bang theory Theories are validated by experimental results. They can be used to predict future observations. They can be tested by experiments. May be modified or replaced Theories can never be conclusively proven because some new observation or experiment always has the potential to reveal a flaw.  A Scientific Law A brief statement that summarizes past observations and predicts future ones – For example, the law of conservation of mass: In a chemical reaction, matter is neither created nor destroyed. Allows you to predict future observations – So you can test the law with experiments Unlike state laws, scientific laws cannot be violated by choice. Law of gravity Laws don’t explain the why Typically related to some mathematical quantitation Everyday Scientific Thinking Observation: Yesterday you went to visit your friend. Soon after you arrived, your eyes began to itch and you started to sneeze. You observed that your friend has a new cat. Everyday Scientific Thinking Hypothesis 1: Perhaps you are allergic to cats. Experiment 1: To test your hypothesis, you leave your friend’s home. Possible outcomes: If the itching and sneezing stop, hypothesis is validated. If the itching and sneezing do not stop, hypothesis is invalid. Everyday Scientific Thinking Observation: Upon leaving your friend’s home, the itching and sneezing stop. The observation supports your hypothesis. Always do more than one experiment. Depending on the complexity of the issue, you can never really do to many experiments. Everyday Scientific Thinking Experiment 2: Visiting a second friend with a cat causes your eyes to itch and you begin to sneeze again, further supporting your hypothesis. Conclusion: The experimental results indicate that you are most likely allergic to cats. Scientific Method For each of the following, indicate whether the step of the scientific method being described is one of the following: (1)observation, (2) hypothesis, (3) experiment, or (4) conclusion. A. Your blender does not work when plugged in. B. The blender motor is broken. C. The plug has malfunctioned. D. The blender does not work when plugged into a different outlet. E. The blender needs repair.  Give me a hypothesis and experiment for the following observations: Observation: Plants in a certain area of the garden outside are growing taller. Observation: Students who sleep more tend to perform better on exams.  What can we do with Chemistry? Pharmaceuticals: antibiotics such as penicillin, and synthesis of various drugs Material Science: polymers, plastics, and synthetic materials Advancements in nanotechnology Agriculture: fertilizers and pesticides Environmental Protection: water treatment alternative energy sources and cleaner technologies Electronics and Technology: semiconductors and conductive materials. battery technology. Forensic Science: chemical analysis for crime scene analysis. Space Exploration: rocket propellants and materials for space exploration. Clean Energy: solar cells and fuel cells. Food Science: food preservation, nutritional content, and taste. Chemistry Happens Everyday to Matter Chemistry happens every day when: food is cooked a car is started silver tarnishes an antacid tablet fizzes in water plants grow taller food is digested At the atomic level chemistry happens when electrons or protons are exchanged Definition of Chemistry Chemistry is the study of substances in terms of: Composition What is it made of? Structu How is it put re together? Properti What characteristics does it es have? Reactio How does it behave with ns other substances? Chemicals Chemicals are substances that always have Things that are not chemicals the same composition and properties such as: Light Sugar (glucose) Heat Water Energy Salt (sodium chloride) Sound Magnetism All things you see are made of chemicals, such as: Reflection soaps and lotions Emotions toothpaste cosmetics clothes computers Matter is defined as anything that has mass and occupies space(has volume). Matter is comprised of atoms: Basic submicroscopic particles that constitute the fundamental building blocks of ordinary matter When two or more atoms come together (bond) in specific geometric arrangements they form molecules: How the particles come together dictates the physical properties of matter. examples  Matter can be classified according to its state—its physical form (i.e., solid, liquid, or gas) based on what properties it exhibits; its composition or the types of particles. The state of matter changes from solid to liquid to gas with increasing temperature. Properties of a Solid Rigid Although the atoms and molecules in a solid vibrate, they do not move around or past each other. Fixed volume and shape Slightly compressible Ice, aluminum, and diamond are good examples Solid: The water of solids. molecules are locked into rigid positions and are close together 24  Properties of a Liquid Definite volume pack about as closely as they do in solid matter, but they are free to move relative to each other. No specific shape Assumes the shape of its container Slightly compressible Liquid: The water Water, alcohol, and gasoline are all substances molecules are still that are liquids at room temperature. close together but can move around to some extent 25  Properties of a Gas No fixed volume or shape Takes on the shape and volume of its container atoms or molecules have a lot of space between them and are free to move relative to one another. Highly compressible Relatively easy to decrease the volume of a gas Gas: The water molecules are far apart and move randomly 26  Physical States of Matter © 2014 Pearson Education, Inc. Classification of Matter  Pure Substances Pure substance: made up of only one component a type of matter with a fixed or definite composition an element is an atom that cannot be chemically broken down into a simpler substance. a compound that is composed of two or more elements chemically combined in the same proportion. Can be broken down into simpler substances. Most elements are chemically reactive and combine with other elements to form compounds such as water or sugar. Elements, one type of element such as copper, Cu; lead, Pb; and aluminum, Al; oxygen, O2 Compounds consists of two or more elements in a definite ratio, like: salt NaCl, table sugar C12H22O11,water H2O  Mixtures Mixture: a substance composed of two or more components: that are mixed, but not chemically combined in different proportions that can be separated by physical methods heterogeneous mixtures: composition varies from one part to another different parts of the mixture are visible portions of a sample have different composition and properties. homogeneous mixtures: the composition is uniform throughout the sample atoms or molecules that compose them mix uniformly have the same composition and properties the different parts of the mixture are not visible Determine which of the following is a pure substance: 1. pasta and tomato sauce 2. aluminum foil 3. helium 4. air 5. Soda (carbonated) water 6. copper wire 7. a pound of sugar Which of the following as a heterogeneous mixture: 8. hot fudge sundae 9. baby shampoo 10. sugar water 11. peach pie 12. nitrox (combination of nitrogen and oxygen for scuba tanks) 13. chocolate chip ice cream  Scientific Measurement Scientific data Qualifiable data are observational. Subjective in nature Examples: blue car spherical planet smooth surface Quantifiable data are measurable (empirical). Objective in nature Uses equipment (e.g., glassware, balance, instrumentation) capable of generating empirical data with standardized UNITS. Examples: 538 ml of water wavelength is 475 nanometers 62g NaCl  Units of Measurement Units are quantities used to specify measurements, which are critical in chemistry. 99.9% of numbers will have a Unit! (Use them) The two most common unit systems are as follows: – Metric system, used in most of the world – English system, used in the United States Scientists use the International System of Units (SI), which is based on the metric system. Measurement Metric SI Length Meters (m) Meters (m) Volume Liters (L) Cubic meters (m3) Mass Grams (g) Kilograms (kg) Time Second (s) Second (s) Temperature Celcius (oC) Kelvin (k) Amount of substance Moles (mol) Moles (mol) Electric Current Ampere (A) Ampere (A) Luminous intensity Candela (cd) Candela (cd)  Length Length is measured in units of meters (m) in both the metric and SI systems units of centimeters (cm) by chemists © 2014 Pearson Education, Inc.  Volume Volume, the space occupied by a substance, is measured using units of m3 in the SI system is commonly measured in liters (L) and milliliters (mL) by chemists © 2014 Pearson Education, Inc.  Mass The mass of an object, a measure of the quantity of material it contains, is measured on an electronic balance has the SI unit of kilogram (kg) is often measured by chemists in grams (g)  Temperature Temperature, a measure of how hot or cold an object is. measured on both the Celsius (ºC) scale and Kelvin (K) scale in the SI system The Thermometer reads 18 ºC and 64 ºF © 2014 Pearson Education, Inc.  Time Time is based on an atomic clock and is measured in units of seconds (s) in both the metric and SI systems. © 2014 Pearson Education, Inc.  Units of Measurement and Their Abbreviations © 2014 Pearson Education, Inc. Units of Measurement On a typical day, a nurse encounters several situations involving measurement. State the name and type of measurement indicated by the units in each of the following: a. A patient’s thermometer reads 38.5 °C.elsius b. A physician orders 1.5 g of cefuroxime for injection. ram c. A physician orders 1 L of a sodium chloride solution to be given iter intravenously. d. A medication is to be given to a patient every 4 h. ours Standard and Scientific Notation Scientific notation is used to write very large or very small numbers Standard Format Scientific Notation Diameter of the Earth 12 800 000 m 1.28 × 107 m Mass of a human 68 kg 6.8 × 101 kg Diameter of a virus 0.000 000 3 cm 3 × 10−7 cm © 2014 Pearson Education, Inc.  Writing Numbers in Scientific Notation A number written in scientific notation contains a coefficient and a power of ten. coefficient power unit of ten 1.5 × 102 m The coefficient is at least 1 but less than 10. The number of spaces moved to obtain a coefficient between 1 and 10 is shown as a power of ten. 0.003 78 = 3.78 × 10−3 52 000. = 5.2 × 104 move decimal 3 spaces right move decimal 4 spaces left © 2014 Pearson Education, Inc.  Some Powers of Ten © 2014 Pearson Education, Inc. Write each of the following in scientific notation: 1. 35000 2. 0.000000016 3. 0.000008 4. 72001 5. 632 6. 0.00253 Is the following number in correct scientific notation? 12.36 x 106 cm Converting Scientific Notation to a Standard Number The standard number is obtained by moving the decimal point according to the powers of 10. Writing Scientific Notation as a Standard Number Write the correct standard number for each. 1. 2.01 x 10-4 2. 1.8 x 105 3. 9.25 x 10-6 4. 2.67 x 10-1 5. 2.67 x 102  Information we need to know about numbers Scientific measurements are reported so that every digit is certain with the exception of the last digit, which is estimated. Consider the following reported value of 5.213: The first three digits are certain; the last digit is estimated. Estimated value 5.213 Known with certainty © 2014 Pearson Education, Inc.  Measured Numbers A measuring tool is used to determine a quantity such as the volume, length or the mass of an object. provides numbers for a measurement called measured numbers.  Reporting Length To report the length of an object, Always indicate the smallest marked place value on your measuring device i.e. tens, ones, tenths, hundredths, thousandths place Observe the numerical values of the marked lines at the end of the object. Estimate the last digit by visually dividing the space between the smallest marked lines. This estimated number is the final digit that is reported for a measured number. It will always be the next decimal place to the right For example: the smallest mark is the tenths place so you will report to the hundredths place Reporting Length: Note the smallest marked place value is the one’s place. The end of the object is between the 4-c m and 5- enti eter c m marks. enti eter Estimate that the end is halfway between the 4- c m and enti eter 5-c m marks and report the value as 4.5 c m. enti eter enti eter We must report to the tenth’s place.  The metric ruler is marked at every 0.1 c m (tenth’s place). enti eter What place must we report to? You can now estimate that the length is halfway between the 4.5-c m and 4.6-c m marks and report the value as 4.55 enti eter enti eter cm. enti eter  The end of the object lines up with the 3-c m mark. enti eter Because the divisions are marked in units of 1 c m , enti eter the estimated digit appears in the tenths place (0.1 c m ). enti eter. l8.... l.... l9.... l.... l10.. cm What is the length of the red line? © 2014 Pearson Education, Inc.  Significant Figures In a measured number, the significant figures, (SFs) are all the digits, including the estimated digit. All nonzero numbers are counted as significant figures. Zeros may or may or may not be significant, depending on the position in the number. © 2014 Pearson Education, Inc.  Rules for Significant Figures © 2014 Pearson Education, Inc.  Learning Check State the number of significant figures in each of the following measurements: A. 0.030 m B. 4.050 L C. 0.0008 g D. 2.80 m Write answers A and C in scientific notation © 2014 Pearson Education, Inc. A. Which answer contains three significant figures? (1) 0.4760 (2) 0.00476 (3) 4.076 × 103 B. All the zeros are significant in (1) 0.00307 (2) 25.300 (3) 2.050 × 103 C. The number of significant figures in 5.80 × 102 is (1) one (2) two (3) three © 2014 Pearson Education, Inc.  Exact Numbers Exact numbers are those numbers obtained by counting items definitions that compare two units in the same measuring system © 2014 Pearson Education, Inc.  Exact Numbers Exact numbers are not measured, do not have a limited number of significant figures, and do not affect the number of significant figures in a calculation. © 2014 Pearson Education, Inc. Measured and Exact Numbers Identify each of the following numbers as measured or exact, give the number of significant figures (SFs) in each of the measured numbers, and explain: a. 0.170 L iter b. 4 knives c. d. 1 m = 100 c m eter enti eter Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Rules for Rounding Off 1. If the first digit to be dropped is 4 or less, then it and all following digits are simply dropped from the number. 22.5489  22.5 (3 sig figs) 2. If the first digit to be dropped is 5 or greater, then the last retained digit is increased by 1. 22.5879  22.6 (3 sig figs) © 2014 Pearson Education, Inc. Round off each of the following numbers to three significant figures: a. 35.7423 m eter b. 0.002627 L iter c. Adjust the following calculated answers to give answers with four significant figures: a. 824.75 cm b. 0.112446 g c. 8.2 L Adjust the following calculated answer to give the answer with 2 significant figures: a. 7851 Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Multiplication and Division with Measured Numbers In multiplication and division, the final answer is written to have the same number of significant figures (SFs) as the measurement with the fewest SFs. For example, 24.65 × 0.67 = 16.5155  17 4 SF 2 SF Calculator Final answer: 2 SF © 2014 Pearson Education, Inc.  Adding Significant Zeros When the calculator answer is a small whole number and more significant figures are needed, we can add one or more zeros. For example, = 4  4.00 3 SF Calculator Final answer © 2014 Pearson Education, Inc. Sample Problem Calculating Answers with the Correct Number of Significant Figures Perform the following calculations with measured numbers and give the answers with the correct number of significant figures. a. b. c. Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved Addition and Subtraction with Measured Numbers In addition, or subtraction, the final answer is written so that it has the same number of decimal places as the measurement having the fewest decimal places. Least precise number. For example, 2.367 Thousandths place + 34.1 Tenths place 36.467 Calculator display 36.5 Answer, rounded off to tenths place © 2014 Pearson Education, Inc. Decimal Places in Addition and Subtraction Perform the following calculations with measured numbers and give each answer with the correct number of decimal places: a. 104 + 7.8 + 40 b. 153.247 − 14.82 For each calculation, round the answer to give the correct number of digits. A. 3235.05 + 19.6 + 2.023 = B. 58.925 – 8.21 = © 2014 Pearson Education, Inc.  Prefixes in Metric / SI System The single letter (g, m, L, or s) represents the “base” unit. Placing a prefix letter will change the value of that number by a factor of 10 or a 10th. The relationship of a prefix to a unit can be expressed by replacing the prefix with its numerical value. When ever you see an “=“ sign; this is an equality © 2014 Pearson Education, Inc. Example of a prefix 1 kilo (1 k) = 1000 The above expression is technically unitless. 1 kilometer (1 km) = 1000 m Prefixes that Increase © 2014 Pearson Education, Inc. Prefixes that Decrease © 2014 Pearson Education, Inc.  The relationship of a prefix to a unit can be expressed by replacing the prefix with its numerical value. – For example: – 1 kilometer (km) = 1000 meters (m) – 1 centimeter (cm) = 0.01 meters (m) What are the numerical values of meters for the following: – 1 nanometer (nm) = ? meters – 1 Megameter (Mm) = ? meters Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Writing Equalities We need equalities so we can write conversions to convert from one unit to another unit (Main Goal) An equality shows the relationship between two different units that measure the same quantity. For example, 1 m is the same length as 100 cm. The equality is written as: 1 m = 100 cm 1 m = 1000 mm 1 cm = 10 mm Equalities Measuring Length The metric length of 1 m is the same length as 10 dm, 100 cm, and 1000 mm. © 2014 Pearson Education, Inc. Equalities Measuring Volume A volume of 1 L or smaller is common in the laboratory. When a liter is divided into 10 equal parts, each is called a deciliter (dL). 1 L = 10 dL 1 L = 1000 mL 1 dL = 100 mL © 2014 Pearson Education, Inc.  Measuring Volume The cubic centimeter (cm3 or cc) is the volume of a cube with the dimensions 1 cm × 1 cm × 1 cm. 1 cm3 = 1 cc = 1 mL A cube measuring 10 cm on each side has a volume of 1000 cm3, or 1 L; a cube measuring 1 cm on each side has a volume of 1 cm3 1cc2 or 1 mL. © 2014 Pearson Education, Inc.  Equalities Measuring Mass When measuring the mass of your body, the mass is measured in kilograms (kg) laboratory samples, mass is reported in grams, milligrams (mg), or micrograms (μg) 1 kg = 1000 g 1 g= 1000 mg 1 mg = 1000 μg 1 mg = 0.001 g © 2014 Pearson Education, Inc. Writing Conversion Factors from Equalities Equalities: use different units to describe the same quantity. Conversion Factors: used to change units. – We’ll use these in equations to answer questions Can be between units of the : – metric system (As seen above) 1 m = 1000 m m eter illi eter – U.S. units 1 lb = 16 oz – Or metric and U.S. units. 2.205 lb = 1 k g ilo ram Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved Writing Conversion Factors and Sig Figs Equalities between two metric quantities or two U.S. system quantities are obtained by definition and are not used to determine significant figures. 1 m = 1000 m m eter illi eter 1 lb = 16 oz 1 min = 60 sec ute onds Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Writing Conversion Factors more Sig Figs Equalities written between metric and U.S. system quantities contain one number obtained by measurement and therefore count toward significant figures. 1 lb = 453.6 g ram An exception is 1 in = 2.54 c m , which is defined as exact. ch enti eter Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved Writing Conversion Factors from Equalities Two Conversion Factors for the Equality 60 min = 1 h Numerator  Denominator  These conversion factors are read as 60 minutes per hour and 1 hour per 60 minutes. The per means “divide.” © 2014 Pearson Education, Inc. Long list of Equalities © 2014 Pearson Education, Inc.  Metric Conversion Factors We can write conversion factors for any metric or metric to U.S relationship. Both conversion factors represent the same quantity; one is just the inverse of the other. Write the conversion factor for the following equalities: 1m = 100cm 2.205lb = 1kg © 2014 Pearson Education, Inc.  Equalities on Food Labels The contents of packaged foods are listed in both metric and U.S. units indicate the same amount of a substance in two different units The can on the right indicates: 5oz = 142g Does this seem reasonable? If: 1lb = 453.6g 1lb = 16oz In the United States, the contents of many packaged foods are listed in both U.S. and metric units. © 2014 Pearson Education, Inc.  Conversion Factors in Problems An equality may also be stated within a problem that only applies to that problem. Write the two conversion factors 1. The car travels at 85 k m /h. ilo eter our 2. The tablet contains 500 m g of vitamin C. illi ram Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Conversion Factors with Powers Sometimes we need to use a conversion factor that is squared or cubed. Refer back to long equalities list. There were no squared or cubed units We will need to mathematically prepare these Distance = length Area = length × length = length2 Volume = length × length × length = length3 © 2014 Pearson Education, Inc. Conversion Factors with Powers To square the equality 1 m = 100 cm, we square both the number and the unit on each side. Equality: 1m = 100cm Area: (1m)2 = (100cm)2 or 1m2 = 10000cm2 Write the new Conversion factor to account for the change in units for area © 2014 Pearson Education, Inc.  Conversion Factors with Powers Use the equality, 1in = 2.54cm to find the conversion factor for cm3. Why would we do this? © 2014 Pearson Education, Inc.  Problem-Solving Process The problem-solving process begins by analyzing the problem: identify the given unit and needed unit write a plan that converts the given unit to the needed unit identify one or more conversion factors that cancel units and provide the needed unit mathematically. (Dimensional analysis) set up a calculation © 2014 Pearson Education, Inc. Algebra (quick review) Units (g, ml, m, etc…) are treated the same as variables (i.e. x) in algebra Examples: a x (b/a) algebraic variables m x (cm/m) units  Setting up the Problem Suppose you need to convert 18.2 mm to meters. Identify the given amount (with units) and the needed units. Write the equality of the units Write the conversion factors Write the equation to obtain the needed unit How many minutes are in 2.75 h? © 2014 Pearson Education, Inc. Using Conversion Factors In radiological imaging such as PET or CT scans, dosages of pharmaceuticals are based on body mass. If Greg weighs 164 lb, what is his body mass in kilograms? 1kg = 2.205 lb What is your volume in in3 if you have 35cm3 of H2O? 1in = 2.54cm Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Using Two or More Conversion Factors Often, two or more conversion factors are required to obtain the unit needed for the answer. For example: How many minutes are in 1.4 days? Minutes and days are separated by hours © 2014 Pearson Education, Inc. A bucket contains 4.65 L water. How many gallons of water is that? Given: 1 L = 1.057 qt and 1 gal = 4 qt Your new car has a fuel consumption of 39.0 mi/gal. Convert this fuel consumption to km/L. Given: 3.785 L = 1 gal and 1 km = 0.6214 mi © 2014 Pearson Education, Inc.  Density Density Compares (provides an equality) the mass of an object to its volume is the mass of a substance divided by its volume is defined as: Equality: g of X = mL of X © 2014 Pearson Education, Inc. Density Substances that have higher densities contain particles that are closely packed together lower densities contain particles that are farther apart Metals such as gold and lead have higher densities because their atoms are packed closely together. © 2014 Pearson Education, Inc. Density, Units In the metric system, densities of solids, liquids, and gases are expressed with different units. The density of a solid or liquid is usually given in grams per cubic centimeter (g/cm3) grams per milliliter (g/mL) The density of a gas is usually given in grams per liter (g/L). © 2014 Pearson Education, Inc.  Density of Common Substances Which of the following liquids float on water?  April 2010, an oil rig in the Gulf of Mexico exploded. Leaked a maximum of 10 million liters a day The density of this oil, 0.8 g/mL, which is less than that of water (1.00 g/mL). It floats on the surface, spreading a thin layer of oil over a very surface area. © 2014 Pearson Education, Inc.  Measuring the Density of a Solid When a solid is submerged, it displaces a volume of water equal to the volume of the solid. Using the picture, determine the density of the solid object. © 2014 Pearson Education, Inc. Scuba divers use lead weights to counteract their buoyancy in water. What is the density of a lead weight that has a mass of 226 g and displaces 20.0 cm3 of water when submerged? © 2014 Pearson Education, Inc.  A student measures the mass of 15.0 mL of water on a scientific scale. The scale reads 14.98 g. What is the density of water? Osmium is a very dense metal. What is its density, in g/cm3, if 50.0 g of osmium has a volume of 2.22 cm3? A 0.258 g sample of high-density lipoprotein (H DL) has ram a volume of 0.215 mL. What is the density of the H DL sample? A 9 lb bowling ball has a volume of 5,453 cc. Will it float in water? 1kg = 2.205 lb Density as a Conversion Factor Greg has a blood volume of 5.9 q t. If the density of blood is 1.06 g /m L , what is uar ram illi iter the mass, in grams, of Greg’s blood? Given: 1 L = 1.057 qt Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Density as a conversion factor If the density of milk is 1.04 g/mL, how many grams of milk are in 0.50 qt? Write the answer in scientific notation. Given: 1 L = 1.057 qt © 2014 Pearson Education, Inc.  Physical Properties Physical properties can be observed or measured without affecting the identity of a substance. Physical properties include shape, color, melting point, boiling point, and physical state of a substance. Table 3.2 Some Physical Properties of Physical properties of a penny include Copper – round shape State at 25 °C Solid – orange-red color (from copper) elsius Color Orange-red – solid state Odor Odorless – shiny luster. Melting Point 1083 °C elsius Boiling Point 2567 °C elsius Luster Shiny Conduction of Electricity Excellent Conduction of Heat Excellent Copyright © 2020, 2017, 2014 Pearson Education, Inc. All Rights Reserved  Physical Changes Physical changes occur when matter undergoes a physical change of state, but its composition remains constant. Water exists in three states, ice, water, and steam. © 2014 Pearson Education, Inc. Physical Changes  Chemical Properties Chemical properties describe the ability of a substance to interact with other substances to change into a new substance Cooking sugar at high temperatures changes its chemical properties. © 2014 Pearson Education, Inc.  Chemical Changes Chemical changes take place when the original substance is converted to a new substance with different physical and chemical properties. For example when iron nails corrode in the presence of water, a new substance forms on them, a red-orange powder called rust (Fe2O3). © 2014 Pearson Education, Inc. Examples of Chemical Changes Physical and Chemical Properties and Changes Physical and Chemical Change Examples Physical Changes Chemical Changes Water boils to form water vapor. Water and cesium combine explosively. Paper is cut into tiny pieces of Paper burns with a bright flame and confetti. produces heat, ashes, carbon dioxide, and water vapor. Sugar dissolves in water to form Heating sugar forms a smooth, caramel- a sugar solution. colored substance. Iron has a melting point of 1538 Iron, which is gray and shiny, combines °Celsius. with oxygen to form orange-red iron oxide (rust). Classify each of the following as physical or chemical properties: A. ice melts in the sun B. copper is a shiny metal C. paper can burn D. a silver knife can tarnish E. a magnet removes iron particles from a mixture Classify each of the following as a physical or chemical change: a. A gold ingot is hammered to form gold leaf. b. Gasoline burns in air. c. Garlic is chopped into small pieces. d. Milk left in a warm room turns sour. e. A mixture of oil and water is separated. f. Burning a candle g. Baking a cake  Temperature Temperature is a measure of how hot or cold an object is compared to another object is measured using a thermometer is measured and reported in Celsius ( C) units in science is the average kinetic energy of the particles © 2014 Pearson Education, Inc.  Temperature Scales Temperature scales are Fahrenheit, Celsius, and Kelvin © 2014 Pearson Education, Inc. Converting Between °F to °C ahrenheit elsius We can write equations that relate these two scales. To obtain °F from °C : ahrenheit elsius and to convert °F to °C : ahrenheit elsius Kelvin Temperature Scale The Kelvin temperature scale has 100 units between freezing and boiling points. 100 K = 100 °C or 1 K = elvin elsius elvin 1 °Celsius adds 273 to the Celsius temperature. TK = TC + 273 is based on 0 K (absolute zero), the lowest elvin possible temperature. 0 K = −273 elvin °Celsius Temperature Comparisons  Given : TF = 1.8TC + 32, solve the following: The normal temperature of a chickadee is 105.8  F. What is that temperature on the Celsius scale? A person with hypothermia has a body temperature of 34.8  C. What is this temperature in  F? On a cold winter day, the temperature is –15  C. What is that temperature in  F? o What is normal body temperature of 37 C in kelvins? Energy is defined as the ability to do work can be classified as either kinetic or potential energy Kinetic energy is the energy of motion. Potential energy is determined by the position of an object or its chemical composition. © 2014 Pearson Education, Inc. Potential or Kinetic Energy? Water in a reservoir behind a dam has potential energy. When the water is released and flows over the dam, its potential energy is converted to kinetic energy.  Learning Check Identify the energy in each example as (1) potential or (2) kinetic. A. rollerblading B. a peanut butter and jelly sandwich C. mowing the lawn D. gasoline in the gas tank © 2014 Pearson Education, Inc. Heat and Units of Energy, Joules Heat is associated with the motion of particles. The faster the particles move, the greater the thermal energy of the substance. The SI unit of energy is the joule (J). 1 k J = 1000 J ilo oule oules Energy Comparison Table 3.6 A Comparison of Energy for Various Resources and Uses Heat and Units of Energy, Calories The unit calorie is the amount of energy needed to raise the temperature of 1 g of water by 1 °C. ram elsius 4.184 joules (J) = 1 calorie (cal) (exact) 1 kilocalorie (kcal) = 1000 calories (cal) Sample Problem Energy Units A defibrillator gives a high-energy-shock output of 360 J. What oules is this quantity of energy in calories?  Elements Elements are pure substances from which everything else is built. Over the centuries, elements have been named for planets mythological figures minerals geographic locations famous people © 2014 Pearson Education, Inc.  Chemical Symbols Chemical Symbols are one or two letter abbreviations for an element’s name. When chemical symbols contain two letters, the second letter is NOT capitalized. Co is the chemical symbol for cobalt. CO specifies there are two elements present, carbon and oxygen. © 2014 Pearson Education, Inc.  Names and Symbols of Elements Aluminum, Al Silver, Ag Gold, Au Sulfur, S © 2014 Pearson Education, Inc. Names and Symbols of Elements Learning the names and symbols for elements will greatly help your learning of chemistry. Name of Element Name of Element Element Symbol Element Symbol Aluminum Al Hydrogen H Barium Ba Iodine I Carbon C Nitrogen N Calcium Ca Oxygen O Chlorine Cl Phosphorus P Names and Symbols of Chemical Elements Complete the following table with the correct name or symbol for each element: Name Symb ol nickel blank bromin blank e blank Zn blank K  The Periodic Table In 1872, Dmitri Mendeleev created the periodic table arranged elements by increasing atomic mass arranged elements into groups with similar properties © 2014 Pearson Education, Inc.  Periods and Groups Periods are horizontal rows of elements Periods 1: contains two elements: H and He Periods 2: contains eight elements: Li, Be, B, C, N, O, F, He Groups are the vertical rows of elements Group 1: contains six elements: Li, Na, K, Rb, Cs, and Fr © 2014 Pearson Education, Inc.  Periods and Groups © 2014 Pearson Education, Inc. Periodic Table Parts The representative elements have group numbers 1A to 8A. Groups 1-2 and 13-18 (new numbering system) The transition elements are in the center of the periodic table 3B to 12B. Groups 3 to 12 (new numbering system)  Group Numbers © 2014 Pearson Education, Inc.  Representative Elements – Groups and Names Group 1A (1), called Alkali metals Li, Na, K, Rb, Cs, and Fr Group 2A (2) called Alkaline earth metals Be, Mg, Ca, Sr, Ba, and Ra Groups 3A (13), 4A (14), 5A (15), and 6A (16) Group 7A (17), called Halogens F, Cl, Br, I, and At Group 8A (18), called Noble gases He, Ne, Ar, Kr, Xe, and Rn © 2014 Pearson Education, Inc. © 2014 Pearson Education, Inc.  Most metals are shiny solids, such as copper (Cu), gold (Au), and silver (Ag). Metals are ductile, can be shaped into wires malleable, can be hammered into a flat sheet good conductors of electricity melted at much higher temperatures than nonmetals solids at room temperature, except for mercury (Hg) © 2014 Pearson Education, Inc. Nonmetals include elements such as hydrogen (H), carbon (C), nitrogen (N), oxygen (O), chlorine (Cl), and sulfur (S). Nonmetals are not especially shiny, malleable, or ductile, and are often poor conductors of heat and electricity typically have low melting points and low densities Metalloids The elements located along the heavy zigzag line are metalloids: B, S i, Ge, As, Sb, Te, and Po boron silicon germanium arsenic antimony Tellurium Polonium ? Properties that are typical of the metals and nonmetals Used as semiconductors Metals, Nonmetals, and Metalloids Table 4.3 Some Characteristics of a Metal, a Metalloid, and a Nonmetal Blank Silver (A g) Antimony (S b) Sulfur (S) Type Metal Metalloid Nonmetal Luster Shiny Blue-gray, shiny Dull, yellow Ductility Extremely ductile Brittle Brittle Malleability Can be hammered Shatters when Shatters when into hammered hammered sheets Conductor Good conductor Poor conductor Poor conductor Uses Manufacture of Hardens lead, colors Manufacture of coins, glass and plastics gunpowder, rubber, jewelry, tableware fungicides Density 10.5 grams per centimeters 6.7 grams per centimeters 2.1 grams per centimeters cubed. cubed. cubed. Melting Point 962°C elsius 630°C elsius 113°C elsius © 2014 Pearson Education, Inc. Learning Check Match the elements to the description: A. Metals in Group 4A (14) (1) Sn, Pb (2) C, Si (3) C, Si, Ge, Sn B. Nonmetals in Group 5A (15) (1) As, Sb, Bi (2) N, P (3) N, P, As, Sb C. Metalloids in Group 4A (14) (1) C, Si, Ge (2) Si, Ge (3) Si, Ge, Sn, Pb Metals, Nonmetals, and Metalloids Use the periodic table to classify each of the following elements by its group and period, group name (if any), and as a metal, a nonmetal, or a metalloid: a. Na, important in nerve impulses, regulates blood pressure b. I, needed to produce thyroid hormones c. Si, needed for tendons and ligaments  Atoms Atoms are the building blocks of everything around us too small to see with the naked eye A small sample of nickel contains many, many nickel atoms. © 2014 Pearson Education, Inc.  The Atom All elements listed on the periodic table are made up of atoms. An atom is the smallest particle of an element. © 2014 Pearson Education, Inc.  Dalton's Atomic Theory The idea of atoms did not become scientific theory until 1808. John Dalton (1766–1844) developed an atomic theory proposing that atoms were responsible for the combinations of elements in compounds. © 2014 Pearson Education, Inc.  Dalton's Atomic Theory 1. All matter is made up of tiny particles called atoms. 2. All atoms of a given element are identical to one another and different from atoms of other elements. 3. Atoms of two or more different elements combine to form compounds. A particular compound is always made up of the same kinds of atoms and the same number of each kind of atom. 4. A chemical reaction involves the rearrangement, separation, or combination of atoms. Atoms are never created or destroyed in a chemical reaction. © 2014 Pearson Education, Inc.  Electrical Charges in an Atom By the end of the 1880s, experiments with electricity showed that atoms were composed of tiny particles, called subatomic particles. it was shown that some subatomic particles in an atom have charge © 2014 Pearson Education, Inc. In 1897, J. J. Thomson discovered that cathode rays were streams of small negatively charged particles called electrons proposed the “plum pudding” model of an atom in which protons and electrons were distributed throughout the atom Structure of an Atom  Structure of an Atom In 1911, Ernest Rutherford worked with J. J. Thomson and developed a new structure for the atom based on Rutherford’s gold foil experiments. © 2014 Pearson Education, Inc.  The Structure of an Atom Rutherford realized that atoms contained a Nucleus small region containing: Protons (positive charged particles) The region of space around the center was occupied by: Electrons (negatively charged particles) © 2014 Pearson Education, Inc. The Structure of an Atom In 1932, James Chadwick discovered that the nucleus of the atom also contained neutral particles called neutrons. Atomic Model Nucleus Protons Neutrons Orbiting electrons around the nucleus  Mass of the Atom The mass of the atom is due to the protons and neutrons in the nucleus. Electrons have a much smaller mass. Chemists use a unit called atomic mass unit (amu), defined as one- twelfth of the mass of the carbon atom with 6 protons and 6 neutrons. The mass of all elements in the periodic table is compared to the mass of this carbon atom. Mass of an Atom On the amu scale, the mass of a proton and a neutron have a mass of about 1 amu.  Learning Check Is each of the following statements true or false? A. The mass of an electron is greater than the mass of a proton. B. Protons have a positive charge, and electrons have a negative charge. C. The nucleus of an atom contains only the protons and neutrons.  Atomic Number The atomic number is specific for each element and the same for all atoms of that element is equal to the number of protons in an atom appears above the symbol of an element Atomic Number 11 Chemical Symbol Na © 2014 Pearson Education, Inc.  Atomic Numbers and Protons Hydrogen has atomic number 1; every H atom has 1 proton. Carbon has atomic number 6; every C atom has 6 protons. Copper has atomic number 29; every Cu atom has 29 protons. Gold has atomic number 79; every Au atom has 79 protons. © 2014 Pearson Education, Inc.  State the number of protons in each atom. A. A nitrogen atom (1) 5 protons (2) 7 protons (3) 14 protons B. A sulfur atom (1) 32 protons (2) 16 protons(3) 6 protons C. A barium atom (1) 137 protons (2) 81 protons(3) 56 protons © 2014 Pearson Education, Inc.  Atoms Are Neutral An atom of any element is electrically neutral; it has a net charge of zero has an equal number of protons and electrons A neutral atom of calcium, atomic number 20, contains 20 protons and 20 electrons. © 2014 Pearson Education, Inc. © 2014 Pearson Education, Inc.  The mass number represents the number of particles in the nucleus is equal to the number of protons + number of neutrons does not appear on the periodic table because it applies to a single atom only © 2014 Pearson Education, Inc.  Mass Numbers - Neutrons We calculate the number of neutrons in an atom from its mass number and atomic number: (mass number – atomic number) = number neutrons Potassium has a mass number of 39 and an atomic number of 19. To find the number of neutrons, subtract the atomic number from its mass number. 39 (mass number) – 19( atomic number) = 20 neutrons Composition of Elements  An atom of zinc has a mass number of 65. A. How many protons are in the nucleus? (1) 30 (2) 35 (3) 65 B. How many neutrons are in the nucleus? (1) 30 (2) 35 (3) 65 C. What is the mass number of a zinc atom that has 37 neutrons? (1) 37 (2) 65 (3) 67 © 2014 Pearson Education, Inc. An atom has 14 protons and 20 neutrons. A. Its atomic number is (1) 14 (2) 16 (3) 34 B. Its mass number is (1) 14 (2) 16 (3) 34 C. The element is (1) Si (2) Ca (3) Se Atomic Symbol The atomic symbol shows the mass number in the upper left corner. shows the atomic number in the lower corner. Atomic symbol for an isotope of magnesium, M g-24 Isotopes Isotopes are atoms of the same element that have different mass numbers have the same number of protons, but different numbers of neutrons © 2014 Pearson Education, Inc.  Atomic Symbols, Subatomic Particles The atomic symbol indicates the number of protons, neutrons and, electrons in a specific isotope of an element. 8 protons 15 protons 30 protons 8 neutrons 16 neutrons 35 neutrons 8 electrons 15 electrons 30 electrons © 2014 Pearson Education, Inc.  Carbon consists of three naturally occurring isotopes, 12C, 13C, and 14C. State the number of protons, neutrons, and electrons in each of these isotopes. Protons Neutrons Electrons © 2014 Pearson Education, Inc.  Learning Check Write the atomic symbols for atoms with the following subatomic particles: A. 8 protons, 8 neutrons, 8 electrons ____ B. 17 protons, 20 neutrons, 17 electrons ____ C. 47 protons, 60 neutrons, 47 electrons ____ © 2014 Pearson Education, Inc. 1. Which of the following pairs are isotopes of the same element? 2. In which of the following pairs do both atoms have 8 neutrons? A. B. C.  Atomic Mass The atomic mass of an element is listed below the symbol of each element on the periodic table calculated based on the weighted average of all naturally occurring isotopes based on its comparison to the mass of 12C not the same as 11 the mass number Na Atomic Mass 22.99 © 2014 Pearson Education, Inc. Using the periodic table, specify the atomic mass of each element: A. calcium __________ B. aluminum __________ C. lead __________ D. barium __________ E. iron __________ Isotopes and Atomic Mass Most elements have two or more isotopes that contribute to the atomic mass of that element. Isotopes of Magnesium Magnesium has three naturally occurring isotopes. The atomic mass of Mg is a weighted average from all the Mg isotopes is not a whole number Calculating Atomic Mass Isotope Mass Abundance 24 Mg = 23.99 amu × 78.70/100 = 18.88 amu 25 Mg = 24.99 amu × 10.13/100 = 2.531 amu 26 Mg = 25.98 amu × 11.17/100 = 2.902 amu Atomic mass of Mg = 24.31 amu 12 Mg 24.31 Given the abundance and mass of these isotopes, calculate the atomic mass of gallium. Gallium is an element found in lasers used in compact disc players. In a sample of gallium, there is: 60.11% of 69Ga (68.93 amu) atoms. 39.89% of 71Ga (70.92 amu) atoms. Solution Given the abundance and mass of these isotopes, calculate the atomic mass of gallium. 69 Ga 68.93 amu × 60.11/100 = 41.43 amu 71 Ga 70.92 amu × 39.89/100 = 28.29 amu Atomic mass Ga = 69.72 amu