AP Chemistry Unit 8 Exam

Consider separate 100.0 g samples of each of the following: NH₃, N₂O, HCN, N₂H₄, and HNO₃. Which of the samples has the least mass of nitrogen?

• N₂H₄
• HNO₃
• HCN

In the reaction N₂(g)+ 3H₂(g) --> 2NH₃(g), how many moles of ammonia would be produced from 1.0 mol of hydrogen and excess nitrogen?

• 0.67 mol
• 3.0 mol
• 0.33 mol

What is the molar mass of NaCl?

• 58.44 g/mol
• 175.3 g/mol
• 2.00 g/mol

What is the mass of 2.00 moles of Ca(OH)₂

• 122.5 g
• 56 g
• 148.2 g

For the reaction C₂H₄(g) + 3O₂(g) --> 2CO₂(g) + 2H₂O(g)if 6.0 mol of CO₂ are produced, how many moles of O₂ were reacted?

• 15.0 mol
• 4.0 mol
• 9.0 mol
• 7.5 mol

Tags

NGSS.HS-PS1-7

A compound has a molar mass of 100 g/mol and the percent composition (by mass) of 65.45% C, 5.45% H, and 29.09% O. Determine the empirical formula and the molecular formula.

• CH₄O and C₃H₁₂O₃
• C₃HO and C₆H₂O₂ 
• C₃H₃O and C₆H₆O₂

Tags

NGSS.HS-PS1-7

Determine the percentage composition (by mass) of H₂SO₄.

• 2.06% H, 32.69% S, 65.25% O
• 33.33% H, 33.33% S, 33.33% O
• 12.38% H, 44.93% S, 42.69% O

Consider the equation 2A + 3B --> C. If 4.0 mol of A is reacted with 4.0 mol of B, which of the reactants is limiting?

• A is limiting because 2 is smaller than 3 (the numbers refer to the coefficients in the balanced equation).
• B is limiting because 3 is larger than 2 (the numbers refer to the coefficients in the balanced equation).
• B is limiting because 4.0 mol and 6.0 mol are needed.

Tags

NGSS.HS-PS1-7

Determine the empirical formula of a compound containing 54.2% F and 45.8% S (by mass).

• SF
  
• SF2
• S2F2
• S2F

Because atoms are so ______________, the standard units of mass are not useful in measurements.

• small
• scattered
• electrically charged