CHEM 1030L
Fundamentals of Chemistry Laboratory
Pre-lab Review - Chemical and Physical Changes
Prepare for Laboratory
1. Review the following textbook section(s)
7.1 – The Mole
7.2 – Molar Mass and Calculations
7.3 – Equations for Chemical Reactions
7.7 – Mass Calculations for Reactions
7.8 – Energy in Chemical Reactions
2. Review the background and procedure for this lab that are posted online.
3. Be able to work the following textbook problems
7.1, 7.9, 7.13, 7.19, 7.29, 7.47, 7.53
4. Be able to summarize the purpose of the experiment.
Two or three sentences summarizing what you will do, what you expect to learn, and what
chemical or scientific principles you expect to understand better. Imagine what you would tell
your roommate over a breakfast of Pop-Tarts about what you will be doing in lab that day.
5. Know and be able to do the following.
a. Be able to define the following terms
 formula weight (also known as: formula mass)
 molar mass
 mole
 mole-mole factor
 products
 reactants
b. Be able to balance chemical equations.
c. Be able to write the formulas for the chemical reactants used in the reaction.
d. Be able to calculate formula weight and molar mass of a chemical substance.
e. Be able to calculate theoretical yield (problems 5.53a, 5.55b, 5.57b).
f. Know the equation for percent yield and be able to calculate percent yield.
g. Mass measurements will be recorded to how many decimal places?
h. The test tube and reaction product will be heated, cooled and weighed at least two times.
The difference between two consecutive weighings must not be any greater than how many
grams?
i. CAUTION: What hazard does HCl pose? What precaution should be used when handling
HCl?
j. CAUTION: How should hot glassware be handled?
k. Where should the clamp be attached to the test tube?
l. At what angle should the test tube be clamped?
m. After the test tube and product have been heated and dried, what must be done before
measuring the mass?
n. What is the purpose of heating the test tube and product more than once?
o. Approximately what mass of sodium carbonate should be obtained for the reaction?
6. Example questions
a. Demonstrate how to calculate the molar mass (or formula weight) of CaSO4.
b. Using a periodic table, calculate the formula weight and molar mass of potassium sulfate.
c. Given the following reaction, write two forms of the conversion factor that converts
between moles of potassium sulfate and moles of calcium sulfate.
Reaction: CaCl2 (aq) + K2SO4 (aq) —> CaSO4 (s) + 2 KCl (aq)
d. Given the above reaction, calculate the number of moles of calcium sulfate that will be
produced from 1.25 moles of potassium sulfate.
e. Given the above reaction, calculate the number of grams of calcium sulfate that will be
produced from 17.5 g of potassium sulfate.
f. Given the above reaction, calculate the number of grams of calcium sulfate that will be
produced from 1.25 moles of potassium sulfate.
g. Write the equation for percent yield. (See the online lab write-up.)
h. If the theoretical yield of a reaction is 7.492 g CaSO4 and the actual yield is 5.983 g CaSO4,
demonstrate how to calculate the theoretical yield of the reaction.
i. Write the chemical formula for sodium carbonate.