Science Chapter 1 Quiz

Matter and Measurement

• Chemistry is the study of matter—its composition, properties, and transformations.
• Matter is anything that has mass and takes up space.
• Naturally occurring matter includes cotton, silk, hair, sand, gemstones, and digoxin.
• Synthetic (human-made) matter includes nylon, polyester, styrofoam, ibuprofen, and many antibiotics.

Chemistry and Matter

• Matter is another word for all the substances that make up our world.
• Examples of matter are antacid tablets, water, glass, and air.

Atoms and Matter

• Chemistry is the study of the composition, structure, and properties of matter, and the changes matter undergoes.
• All matter is made up of basic building blocks called atoms.

Chemicals

• Chemicals are substances that have the same composition and properties wherever found.
• Many chemicals are made by chemists and used in everyday products.
• Examples of chemicals commonly found in toothpaste include calcium carbonate, sorbitol, sodium lauryl sulfate, and titanium dioxide.

Chemicals in the Kitchen

• Examples of common chemicals found in kitchens include silicon dioxide (glass), chemically treated water, metal alloys, natural polymers, and natural gas.

Study Check

• Which of the following contains chemicals.
• Only fruit, milk, and breakfast cereal contain chemicals.

1.1 Scientific Method

• The scientific method is a set of general principles that helps describe how a scientist thinks.
• First, observations of nature are made , followed by questions about what is observed. A possible explanation (hypothesis) is proposed. Following this, experiments are conducted to test the hypothesis. Lastly, a conclusion about whether the hypothesis is true or false is drawn from the analysis of the experimental results.

Discovery of Penicillin

•  Penicillin is a substance discovered by scientific methods

Using the Scientific Method

• Suppose you are visiting a friend. Upon arrival, you begin to sneeze.
• You observe that your friend has a new cat.
• You ask why you are sneezing and form a hypothesis that you are allergic to cats.
• You visit other friends who have cats to test your hypothesis.
• If you sneeze after leaving the homes with cats, you can conclude that your hypothesis is correct.
• Through observations you may determine that you are allergic to cat hair and dander.

1.2 Matter

• Elements and compounds, atoms and molecules, pure and impure states of matter, physical and chemical properties are all part of the categorization of matter.

States of Matter

•  A solid has a definite volume and shape.
• A liquid has a definite volume but takes the shape of its container.
• A gas has neither a definite volume nor a definite shape. They expand to fill the volume and shape of whatever container they are placed in. 

Properties of Matter

• A physical change alters the material without changing its composition (e.g., melting ice; or boiling liquid water to steam).
• A chemical change is a chemical reaction that converts one substance into another (e.g., metabolizing an apple for energy; oxygen and hydrogen combining to form water).

Practice Question

• Which is an example of a physical change?
•  Polishing tarnished silver; or melting an ice cube in a glass of soda.

States of Matter: Properties of Matter

• Physical properties can be observed or measured without changing the material's composition. 
• Examples include boiling point, melting point, solubility, color, and odor.

A Pure Substance

• A pure substance is composed of a single component.
• It has a consistent composition, regardless of sample size or origin.
• It cannot be broken down into other pure substances through a physical change.

Classification of Matter: Element vs. Compound

• An element cannot be broken down into simpler substances by a chemical change.
• A compound is formed by chemically joining two or more elements.

A Mixture

• A mixture is composed of more than one component and can have a varying composition
• it can be separated into components by a physical change

Homogenous Mixture

• A homogeneous mixture has a uniform composition throughout.
• The different parts of the mixture are not visible (e.g., copper and zinc in brass).

Bronze

• Bronze is an alloy (a homogenous mixture). It contains primarily copper and tin.

Heterogeneous Mixture

• A heterogeneous mixture does not have a uniform composition throughout.
• The different parts of the mixture are visible (e.g., water and copper).
• Mixtures like salads or mixed candies are heterogeneous.

Classification of Matter - Recap

• Matter is anything with mass and volume.
• Matter can be classified as pure substances or mixtures.
• Pure substances can be elements or compounds.
• Mixtures can be homogeneous or heterogeneous.

1.3 Measurements

• Measurements are composed of a number and a unit.
• The metric system uses units like meters (length), liters (volume), and grams (mass).

Measurement: The Metric System of Units

• Each type of measurement has a base unit. The prefixes of the unit names indicate if the unit is larger or smaller than the base unit. 

Measurement: The Metric System of Units

• Other units are related to the base unit by a power of 10.
• The prefix of the unit name indicates if the unit is larger or smaller than the base unit.

Measurement: Measuring Length

•  1 kilometer = 1,000 meters, 1 millimeter = 0.001 meters, and 1 centimeter = 0.01 meters.

Measurement: Measuring Mass

• Mass is a measure of the amount of matter in an object.
• Weight is the force that matter feels due to gravity.
• 1 kilogram (kg) = 1,000 grams (g), 1 milligram (mg) = 0.001 grams (g).

Measurement: Measuring Volume

• Volume is the amount of space occupied.
• Volume = Length x Width x Height = cm³
• 1 kiloliter (kL) = 1,000 liters (L), 1 milliliter (mL) = 0.001 liters (L) 

Significant Figures

• Exact numbers result from counting objects or are a part of a definition (e.g., 10 fingers, 1 m = 100 cm).
• Inexact numbers are from measurements that have some uncertainty (e.g., a length measurement).

Chemistry and Measurement

• Estimate the length of the piece of wood (based on a ruler).

Chemistry and Measurement

• What value best represents the temperature indicated on the thermometer (based on a diagram of a thermometer)?
• Use 4.85°C based on significant figures

1.4 Expressing Numbers

• Scientific and standard (i.e., decimal) notation are for expressing numbers.

Scientific Notation

• Scientific notation is used for very small and large numbers.
• The format is y x 10^x.

Significant Figures

• All nonzero digits in a measurement are always significant.
• A zero counts as a significant figure when it's between two nonzero digits, or at the end of the number with a decimal place. A zero at the beginning of the number is not significant

Significant Figures

• Rules for multiplication and division: The answer has the same number of significant figures as the original number with the fewest significant figures.
•  Rules for addition and subtraction: The answer has the same number of decimal places as the original number with the fewest decimal places.

1.5 Expressing a Measurement

• Rounding and significant figures are used in measurements.

Measurement: Measuring Volume

• Volume = length x width x height = cm³ = 1mL = 1cm³ = 1cc
• 1.000 liters is equal to 1000 mL

Significant Figures: Rules for Rounding Off Numbers

• If the digit to be dropped is less than five, just drop it and the remaining digits.
• If the digit to be dropped is five or greater, round up the last digit to be retained by adding 1.

Chemistry and Measurements

• Which of the following values best represents the values displayed on a thermometer?

1.6 SI System

• The International System of Units (SI system) is used for a variety of measurements.
• Equivalents between SI and non-SI units and Prefixes used with SI units can be helpful.
• The density calculation is also part of the SI system.

Units of Measurement: Metric and SI

• The chart shows the metric and SI units for length, volume, mass, temperature, and time.

Length: Meter (m), Centimeter (cm)

• The meter is the SI unit of length. 
• 1 meter is equal to 100 cm. 
• The meter is slightly bigger than a yard. 

Volume: Liter (L), Milliliter (mL)

• The liter is the metric unit for volume, and is slightly larger than a quart. 
• 1 liter (L) = 1000 milliliters (mL).
• 1 L = 1.06 qt, 946 mL = 1 qt

Mass: Gram (g), Kilogram (kg)

• The kilogram (kg) is the SI unit of mass.
• 1 kg = 1000 g, 1 kg = 2.2 lb, and 454 g= = 1 lb. The gram (g) is the metric unit of mass, used for smaller masses. 

Temperature: Celsius (°C), Kelvin (K)

• Temperature is expressed as Celsius (°C) in the metric system and Kelvin (K) in the SI system.
• Water freezes at 0°C and boils at 100°C.

Time: Second (s)

• The second (s) is the SI and metric unit of time.

Study Check

• What are the SI units for volume, mass, length, and temperature?

Solution

• SI units for volume are cubic meters (m³).
• SI unit for mass is the kilogram (kg).
• SI unit for length is the meter (m).
• SI unit for temperature is Kelvin (K).

Temperature

• Temperature is a measure of kinetic energy

Temperature (Conversion Factors)

• Three temperature scales are used: degrees Fahrenheit (°F), degrees Celsius (°C), and Kelvin (K).
• Conversion formulas are needed to convert from one scale to another.

Temperature: Comparing the Three Temperature Scales

• Shows the different scales for Fahrenheit, Celsius, and Kelvin. These scales are used to compare and measure temperature

Temperature: A Comparison of Temperatures

• A table shows a comparison of temperatures in Fahrenheit, Celsius, and Kelvin for various examples.

Temperature Conversion

• To convert a given temperature in Celsius (°C) into Fahrenheit (°F), the formula °F = 1.8(°C) + 32 can be used.

Temperature

• The temperature in France is 31°C

Density

• Density is the ratio of mass to volume.
• Density = mass/volume

Density

• An average human brain has a capacity of 1.24 L and a mass of 1.30 kg; what is the density of the average human brain?
• The density of the average human brain is 1.05 kg/L

Density

• One thing that does not influence density is amount of substance present.
• Properties that are not influenced by the amount of substance present are called intrinsic properties (e.g. color, boiling point, melting point).

Extrinsic Properties

• Properties influenced by the amount of substance present are called extrinsic properties; (e.g. mass, volume, solubility).

Why does ice float on water?

• The less dense substance will float on top of the denser substance.

Density of Solids

• The density of a solid can be determined by dividing the mass of the object by its volume.

Density Using Volume Displacement

• Find the volume by subtracting the initial liquid volume from the final liquid volume.

Study Check

• What is the density of a 48.0-g metal sample if the liquid in a graduated cylinder rises from 25.0 ml to 33.0 ml?
• The density is 6.0 g/mL

1.7 Converting Units

• Conversion factors are used in converting between units (e.g., converting from lbs to kg). These conversion factors have to be applied in a proper way to obtain the correct units and significant figures. 

Problem Solving Using the Factor Label Method: Conversion Factors

• A conversion factor is something that converts a given unit of measurement to another unit of measurement.
• Conversion factors are used in different calculations that require conversions like converting from grams to kilograms.

Using the Factor-Label Method

• The factor-label method is a way to solve problems using conversion factors.
• The method is used to convert from one unit to another unit of measurement.

Using the Factor-Label Method

• Method for solving problems using conversion factors to convert from one unit of measurement to another.
• Make sure that all undesired units cancel out and only the desired unit is left.

Using the Factor-Label Method

• This method is helpful to solve problems by setting up a calculation with the given original measurements and desired units to solve for missing units (like converting from mg to g).

Using the Factor-Label Method

• Identify the original quantity and the desired quantity.
• Write out the conversion factors needed to solve the problem, and choose the appropriate conversion factor needed to solve problems
• Set up the problem; solve the problem, and write the answer with the correct number of significant figures.

Using the Factor-Label Method

• For problems requiring multiple conversion factors, arrange successive factors so the units in the denominator of one factor cancel the units in the numerator of the preceding factor.

Density (a conversion factor)

• Density is a physical property that relates the mass of a substance to its volume, an expression of how much matter is compacted into a given space (measured by mass/volume).
• To convert volume (mL) to mass (g): g/mL x mL = g
• To convert mass (g) to volume (mL): mL/g x g = mL (The inverse of density is used to find volume when given mass )

Density: Solving Problems with Density

• Density is used as a conversion factor to solve problems.

Density

• What is the mass in grams of 85.32 ml of blood plasma with a density of 1.03 g/ml?  
• The mass is 87.9 g

Table 2.8 Densities of Some Common Substances

• Table showing the densities of various common substances (solids, liquids, or gases). 

Density and Specific Gravity

• Specific gravity compares density of a substance with the density of water at the same temperature.
• Specific gravity is unitless (density (substance)/ density (water) = specific gravity)

Test your understanding of scientific concepts with this quiz covering hypotheses, the states of matter, and the scientific method. Each question will challenge your grasp on foundational scientific principles and definitions. Perfect for students studying physical science.