AP Chemistry: Chemical Reactions & Stoichiometry 2

Question 1

How many moles of O2 are required to completely combust 2 mol of C3H8 (propane)?

Accepted Answer

10 mol

Answer

5 mol

Answer

3 mol

Answer

7 mol

Question 2

What is the molar mass of calcium phosphate, Ca3(PO4)2?

Accepted Answer

310.18 g/mol

Answer

215.21 g/mol

Answer

278.18 g/mol

Answer

190.30 g/mol

Question 3

In the reaction 2Al + 3Cl2 -> 2AlCl3, if 4 mol Al react, how many mol AlCl3 form?

Accepted Answer

4 mol

Answer

2 mol

Answer

3 mol

Answer

6 mol

Question 4

Which quantity equals one mole of any substance?

Accepted Answer

6.022 x 10^23 representative particles

Answer

1 gram of the substance

Answer

22.4 grams at STP

Answer

The atomic number in grams

Question 5

What is the percent by mass of nitrogen in NH4NO3?

Accepted Answer

35.0%

Answer

17.5%

Answer

23.3%

Answer

46.7%

Question 6

A reaction produces 18.0 g of water from an actual yield experiment whose theoretical yield is 24.0 g. What is the percent yield?

Accepted Answer

75.0%

Answer

133%

Answer

60.0%

Answer

42.0%

Question 7

How many atoms of oxygen are present in 0.500 mol of CO2?

Accepted Answer

6.02 x 10^23

Answer

3.01 x 10^23

Answer

1.51 x 10^23

Answer

1.20 x 10^24