# Chapter 3 Problem Solving in Chemistry

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```					Chapter 3: Problem Solving in
Chemistry

MRS. PIERCE
3.2 Techniques of Problem Solving

 Steps to follow when solving problems….
 Identify the Unknown
   What should units be?
   Identify what is Known or Given
   Any extra/unnecessary information?
   Plan a Solution
 Look up any constants or equations (if necessary)
 Compare Units of Given and of Unknown
   Do the Calculations
   Always double-check units/work!
   Finish Up
   Final Check!
3.3 Conversion Factors

 Conversion Factors (equivalent measurements)
are commonly used in Chemistry to solve problems!
   Examples…
 \$1.00 = 4 Quarters = 10 Dimes = 20 Nickels = 100 Pennies
 1 m = 10 dm = 100 cm = 1,000 mm
 1 kg = 1,000 g
 1 g = 10 dg = 100 cg = 1,000 mg
 1 L = 1,000 mL
3.4 Dimensional Analysis

 In dimensional analysis you use the units
(dimensions) that are part of measurements to help
solve (analyze) a problem.
   Follow the in-text example on pages 65-67!
   Mrs. Pierce is preparing a laboratory experiment. There are 6
laboratory groups that will be completing the experiment. The
experiment calls for 10.0 g of sodium chloride, NaCl. Mrs. Pierce
has located 123.0 g of NaCl in the stock room. Does she have
enough for all of the laboratory groups?
3.5 Converting Between Units

 When completing a chemistry experiment/problem,
one will often have to express measurements in a
unit that is different from the one given in the
problem!
   See Examples 4 & 5 in the book (page 69)
3.6 Multistep Problems

 Many problems in Chemistry are more easily solved
if broken down into simpler steps.
   More than one conversion factor is often necessary to solve a
problem!
   See Examples 6 & 7 (pages 72 & 73)
3.7 Converting Complex Units

 When a problem involves units containing two types
of measurements (densities, speeds, etc.), it is
critical to keep track of units that have been
cancelled/converted!
   Always double check units when solving problems!!!
   See Example 8 (page 75)

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