Percent Composition
What is the percent composition of oxygen in water?
88.8%
Explain what theoretical yield is.
Theoretical yield is how much of something you should make in a given reaction based off of how much of the reactants you start with.
Given the equation:
1 P4O10 + 6 H2O ---> 4 H3PO4
What do the numbers 1, 6 and 4 represent?
The moles of that substance.
When a stoichiometry problem involves mass in grams, where do we get that information from?
The periodic table
Where do you get the numbers for the second step of a mass to mass problem?
from the balanced chemical equation (the coefficients)
What is the percent composition of sodium in NaCl?
39.34%
In lab, you make 43.2 g of FeCl3. Your lab mate calculates that you should have made 50 g of FeCl3. Calculate the percent yield.
86.4%
1 P4O10 + 6 H2O ---> 4 H3PO4
If you have 0.5 moles of water, how many moles of H3PO4 will be made?
0.33 moles H3PO4
CH4 + 4 Cl2 ---> CCl4 + 4 HCl
If 3.25 moles of Cl2 react, how many grams of HCl will be produced?
118.5 g HCl
Where do you get the numbers for the first and third steps of a mass to mass problem?
Off of the periodic table (molar masses)
What is the percent composition of potassium in K2S?
70.92%
Before doing a lab you calculate that you should make 4.2 g of copper. At the end of your lab you actually produce 0.1 g. Calculate your percent yield.
2.38%
1 P4O10 + 6 H2O ---> 4 H3PO4
If you have 2.75 moles of water, how many moles of P4O10 are needed?
0.46 moles P4O10
CH4 + 4 Cl2 ---> CCl4 + 4 HCl
If 68 g of CCl4 are formed, how many moles of HCl are formed?
1.77 moles of HCl
2 AgNO3 + H2S ---> Ag2S + 2 HNO3
If you have 75 g of AgNO3, how many grams of Ag2S will be produced?
54.7 g Ag2S
What is the percent composition of nitrogen in lithium nitrate?
20.32%
CH4 + 2 O2 ---> CO2 + 2 H2O
If you have 3.5 moles of CH4 and 5 moles of O2, which is the limiting reactant?
The O2
C3H8 + 5 O2 ---> 4 H2O + 3 CO2
If 10.5 moles of H2O are produced, how many moles of C3H8 were reacted?
2.63 moles C3H8
2 Na3PO4 + 3 CaCl2 ---> Ca3(PO4)2 + 6 NaCl
5.9 moles of calcium chloride will produce how many grams sodium chloride?
689.59 g sodium chloride
2 AgNO3 + H2S ---> Ag2S + 2 HNO3
If you produce 46.7 g of hydrogen nitrate, how many grams of H2S do you need?
12.63 g of H2S
What is the percent composition of oxygen in calcium hydroxide
43.12%
2 Na3PO4 + 3 CaCl2 ---> Ca3(PO4)2 + 6 NaCl
If 4.62 moles of Na3PO4 react with 7.62 moles of CaCl2, which is the limiting reactant?
The Na3PO4.
C3H8 + 5 O2 ---> 4 H2O + 3 CO2
If I want to make 12 moles of carbon dioxide, how much oxygen do I need to start out with?
20 moles O2
2 Na3PO4 + 3 CaCl2 ---> Ca3(PO4)2 + 6 NaCl
If you have 100 grams of sodium phosphate, how many moles of calcium phosphate will be produced?
0.3 moles of calcium phosphate
2 Na3PO4 + 3 CaCl2 ---> Ca3(PO4)2 + 6 NaCl
If 150 grams of sodium phosphate react, how many grams of calcium phosphate are made?
141.9 g calcium phosphate