Part 1
Define stoichiometry.
A) A section of chemistry related to stocks
B) A section of chemistry that involves reactants and/or products in a chemical reaction to determine its quantitative data.
C) A section of chemistry that studies the chemistry of molecular subunits.
B) A section of chemistry that involves reactants and/or products in a chemical reaction to determine its quantitative data.
What is a limiting reagent/reactant?
-A reactant that gets consumed first in a chemical reaction
What is an excess reagent?
A reactant that is not completely used up once the reaction finishes AKA left over
What is the mole ratio between oxygen and magnesium oxide below?
2 Mg + O2 → 2 MgO
1:2
Define theoretical yield.
Amount of product that is expected to be produced in a reaction (in theory, on paper).
Is this true about stoichiometry? A chemical reaction does not have to be balanced first in order to complete a stoichiometry problem.
False
What is the Percent Yield formula?
Actual/Theoretical X 100%
Maximum amount of product that can be produced is the same as ____
Theoretical Yield
Define mole ratio.
A) The ratio between the amount of moles that two compounds have in a reaction
B) The ratio between the distance of moles of an element from its surroundings
C) The ratio between the mass of moles that three compounds have in a reaction
A) The ratio between the amount of moles that two compounds have in a reaction
Which of these measurements are used in stoichiometry?
A) Moles
B) Mass
C) All of the above
C) All of the above
If you react 15 moles of Mg with 20 moles of O2, which one is the limiting reagent?
2 Mg + O2 → 2 MgO
Mg
How many moles of KClO3 must decompose to make 9 moles of O2?
2 KClO3 → 2 KCl + 3 O2
6 moles
Is this true? Mole ratios are found from the balanced equation of a reaction.
True
Define experiemental yield.
The amount of product you actually make during a lab experiment. (also known as actual yield)
Which of the below is true for limiting reagents?
A) It is consumed in a chemical reaction until a certain point
B) It is fully consumed
C) It is consumed and it turns into excess reagents as waste
B) It is fully consumed
If you react 75 moles of Mg with 50 moles of O2, how much MgO can be produced?
2 Mg + O2 → 2 MgO
75 MgO
How many moles of solid aluminum are required to produce 4.5 moles of aluminum oxide?
4 Al + 3 O2 → 2 AlO3
9.0 moles
What is the molar mass of Mg(OH)2? Include the units needed
58.3 g/mol
From the equation N2 + 3 H2 → 2 HN3, how many moles of HN3 are created if you are given 100 moles of H2?
150 moles
You are making cheese burgers for our class. To make 1 cheese burger, you need 2 buns, 1 piece of cheese, and 1 burger.
You are given 60 burger buns, 25 pieces of cheese, and 30 burgers. How many cheese burgers can you make and what is your limiting reactant?
25 cheese burgers - LR is the cheese
35 moles of KClO3 decompose into how many moles of KCl?
2 KClO3 → 2 KCl + 3 O2
35 moles
On paper, you predict you should be able to make 65.7 moles of oxygen gas. When you complete the lab during class, you only produce 43.25 moles of oxygen gas. What is the percent yield? (Round up to the nearest percentage)
66%
True or false. You want your percent yield to be as low as possible.
False - You want it to be close to 100% as much as possible!
If you react 45 moles of Mg with 20 moles of O2, which one is the excess reagent?
2 Mg + O2 → 2 MgO
Mg