Introductory Chemistry Chapter 3 Measurement PDF

Mark S. Cracolice Edward I. Peters www.cengage.com/chemistry/cracolice Chapter 3 Measurement and Chemical Calculations Mark S. Cracolice The University of Montana Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives (3.1) Write in...

Mark S. Cracolice Edward I. Peters www.cengage.com/chemistry/cracolice Chapter 3 Measurement and Chemical Calculations Mark S. Cracolice The University of Montana Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives (3.1) Write in scientific notation a number given in ordinary decimal form; write in ordinary decimal form a number given in scientific notation Use a calculator to add, subtract, multiply, and divide numbers expressed in scientific notation (3.2) Convert an equivalency into two conversion factors (3.3) Learn and apply the algorithm for using conversion factors to solve quantitative problems Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives (3.4) Explain why the metric system of measurement is used in the sciences (3.5) State and write with appropriate metric prefixes the relationship between any metric unit and its corresponding kilounit, centiunit, and milliunit Using Table 3.1, state and write with appropriate metric prefixes the relationship between any metric unit and other larger and smaller metric units Distinguish between mass and weight Identify the metric units of mass, length, and volume Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives Given a mass, length, or volume expressed in basic metric units, kilounits, centiunits, or milliunits, express that quantity in the other three units Given a mass, length, or volume expressed in any metric units and Table 3.1 or the equivalent, express that quantity in any other metric unit (3.6) Given a description of a measuring instrument and an associated measurement, express the measured quantity with the uncertain digit in the correct location in the value State the number of significant figures in a given quantity Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives (3.7) Round off given values to a specified number of significant figures Add or subtract given measured quantities and express the result in the proper number of significant figures Multiply or divide given measured quantities and express the result in the proper number of significant figures (3.8) Given a metric–USCS conversion factor and a quantity expressed in any unit in Table 3.2, express that quantity in corresponding units in the other system Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives (3.9) Given a temperature in either Celsius or Fahrenheit degrees, convert it to the other scale Given a temperature in Celsius degrees or kelvins, convert it to the other scale (3.10) Write a mathematical expression indicating that one quantity is directly proportional to another quantity Use a proportionality constant to convert a proportionality to an equation Copyright ©2016 Cengage Learning. All Rights Reserved. Textbook Learning Objectives Given the values of two quantities that are directly proportional to each other, calculate the proportionality constant, including its units Write the defining equation for a proportionality constant and identify units in which it might be expressed Given two of the following for a sample of a pure substance, calculate the third: mass, volume, and density Copyright ©2016 Cengage Learning. All Rights Reserved. Course Learning Objectives (CLO) CLO 3.1 Define the common SI units and metric prefixes. CLO 3.2 Use dimensional analysis to convert between units of measure. CLO 3.3 Use of scientific notation and significant digits. Copyright ©2016 Cengage Learning. All Rights Reserved. Scientific Notation Method of writing numbers in the form: a.bcd × 10e Coefficient: a.bcd Number equal to or greater than 1 and less than 10 Exponential: 10e Exponent: Number e in 10e Whole number, may be positive or negative Copyright ©2016 Cengage Learning. All Rights Reserved. Conversion of Decimal Number to Scientific Notation Rewrite the number, place the decimal after first nonzero digit and write ×10 Count the number of places the decimal in the original number moved to its new place Write the number as the exponent of 10 Compare original number with new coefficient If the coefficient is smaller than original number, exponent has positive value If the coefficient is larger than original number, exponent has negative value Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise Example: Convert 0.00818 dg to scientific notation Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise Example: Convert 51,000,000 kg to scientific notation Copyright ©2016 Cengage Learning. All Rights Reserved. Conversion of Scientific Notation to Decimal Multiply the coefficient with the exponent Exponent gives the number of places the decimal point has to be moved Based off priority! Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise Example: Convert 3.49 × 10 -11 to decimal form Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise Example: Convert 5.16 × 104 to decimal form Copyright ©2016 Cengage Learning. All Rights Reserved. Key takeaways: Scientific Notation Know your Coefficients! For numbers less than 1: Simply count the zeros, and that will be your number (in negative) for the exponent For numbers at 1 or greater, include all numbers excluding highest priority number! Copyright ©2016 Cengage Learning. All Rights Reserved. Quantity In chemistry, quantities must be expressed as a product of a value and a unit Value × Unit = Quantity How many seconds are in 50 minutes? We know that there are 60 seconds in 1 minute. Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise You're currently driving at 60 mph, how many miles would you drive per minute? Copyright ©2016 Cengage Learning. All Rights Reserved. Equivalency And Conversion Factors Equivalency: Expression stating that two quantities with different units represent the same property Conversion factor: Relationship between different units of measurement that express the same quantity, written as fraction Two conversion factors result from each equivalency Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise Write equivalency and conversion factors for the following One day is 24 hours, how many minutes are there in One day? Copyright ©2016 Cengage Learning. All Rights Reserved. Algorithm to Solve a Quantitative Chemistry Problem Step 1 Analyze the problem statement Determine the given quantity: Value x unit Describe the property of the given quantity Describe the property of the wanted quantity State the unit of the wanted quantity Step 2 Identify equivalences or an algebraic relationship that may be needed to solve the problem Change the equivalencies to conversion factors or solve algebraic equation for wanted variable Copyright ©2016 Cengage Learning. All Rights Reserved. Algorithm to Solve a Quantitative Chemistry Problem Step 3 Construct the solution setup Confirm that the units cancel correctly and calculate the value of the answer Step 4 Check the solution at two levels Making sense - Is the value reasonable? What was learned Copyright ©2016 Cengage Learning. All Rights Reserved. Active Exercise Calculate the number of weeks in a year Copyright ©2016 Cengage Learning. All Rights Reserved. Table 3.1 - Metric Prefixes Copyright ©2016 Cengage Learning. All Rights Reserved. Metric Takeaways 1 Gram = 100cg, 0.001kg, 1000mg 1 Meter = 100cm, 0.001km, 1000mm SI Unit of Length: Meter SI Unit of Mass: Kg SI Unit of Volume: Cubic Meter Know your conversions between Meters and Grams! Keep a chart handy on exam day! Copyright ©2016 Cengage Learning. All Rights Reserved. M/C Convert these quantities from scientific notation to decimal (standard) form. 8.4 x 105 mL Copyright ©2016 Cengage Learning. All Rights Reserved.