Unit 6 AP Chemistry Review

A compound is 69.9% iron and 30.1% oxygen by mass. How much iron could by obtained from 5.41 grams of the compound?

• 0.0969 mol
• 0.0677 mol
• 0.865 mol
• 0.0292 mol 

Tags

NGSS.HS-PS1-7

What is the percent of oxygen by mass in a pure sample of FeCr₂O₄?

• 13%
• 29%
• 7.1%
• 52%

Tags

NGSS.HS-PS1-7

Calculate the percent composition of (NH₄)₂CO₃. The correct percentages are 

• 25.65% N, 5.670% H, 12.50% C, 46.18% O
• 39.15% N, 8.407% H, 12.50% C, 39.94% O
• 29.15% N, 8.407% H, 12.50% C, 49.94% O
• 32.74% N, 6.850% H, 15.67% C, 44.74% O

What is the % copper, by weight, in copper(II) oxide? 

• 44.4% 
• 88.8%
• 79.9%
• 66.5% 

A substance has a molar mass of 60 g/mol with 40.0 percent carbon, 6.7 percent hydrogen, and 53.3 percent oxygen. What is its empirical formula?

• C₂H₄O₂ 
• C₂H₂O₄
• CHO₂ 
• CH₂O

The mass percentage composition of cryolite, a compound used in the production of aluminum, is 32.79% Na, 13.02% Al, and 54.19% F.What is the empirical formula of the compound?

• Na₂Al₆F 
• Na₂AlF₅
• Na₃AlF₆
• Na₃Al₄F

Tags

NGSS.HS-PS1-1

An elemental analysis of compound X shows that the mass percentage composition of the compound is 26.86% C and 2.239% H, with the remainder being oxygen. A mass spectrum of X yields a molar mass of 90.0 g/mol. Write the empirical formula of X.

• C₂HO₂
• CHO₂
• C₂H₂O
• CH₂O 

An elemental analysis of compound X shows that the mass percentage composition of the compound is 26.86% C and 2.239% H, with the remainder being oxygen. A mass spectrum of X yields a molar mass of 90.0 g/mol. Write the molecular formula of X.

• CHO₂
• C₂H₂O₄
• C₂H₂O
• CH₂O 

Tags

NGSS.HS-PS1-1

A hydrocarbon (an organic compound containing only C and H) is found to be 7.74% H. If the molecular weight is known to be between 70 and 85 amu, find the molecular formula.

• C₆H₁₀
• C₅H₁₂
• C₆H₁₂
• C₆H₆

Determine the molecular formula of the compound with an empirical formula of CH and a formula mass of 78.110 amu.

• C₈H₈ 
• C₅H₅ 
• C₆H₆
• C₄H₄

Tags

NGSS.HS-PS1-7