# Mass Stoichiometry Video Quiz

Stoichiometry is the study of what kind of relationship in a chemical reaction?
quantity
quality
reactants
products
What do the coefficients in a balanced chemical equation always represent?
mole ratio
gram ratio
both choices are correct
All stoichiometry problems involve starting with information about one substance and finding information about a different substance. What is always involved in “making the switch?” (Choose all correct answers)
the mole ratio
the balanced equation
the subscripts from the formulas
You are given the mass of one of the reactants in a chemical reaction and asked to find the mass of one of the products. What is your first step?
Check to make sure the equation is balanced.
Get out a balance.
“Make the switch” using the mole ratio
Give up – it’s too hard!
You are working in the lab and find the mass of one of the products in a chemical reaction. What is this called?
actual yield
theoretical yield
percent yield

How many grams of water will be produced if 2.6 grams of oxygen gas react? 2H2 + O2 → 2H2O

2.9 g H2O

2.6 g oxygen gas react with excess hydrogen gas to produce 2.4 g water. What is the percent yield? 2H2 + O2 → 2H2O