4/15(M): Chemistry Checkpoint #39

• Total Molar Mass of Element in Compound
• Total Molar Mass of Compound
• Molar Mass of a Single Element
• 100

If a compound sample contains 40g of calcium, 12g of carbon, and 48g of oxygen, what is the percent composition by mass of calcium?

Hint: The total mass is 100g

• 40%

• 50%

• 60%

• 70%

• 11%

• 89%

• 67%

• 33%

The percentage difference between the correct answer and wrong answer is

• graph
• density
• percent error
• error

Density was calculated in an experiment and was found to be 86 g/cm³. The actual density was 78 g/cm³. What is the percent error?

• 12%

• 10%

• 8%

• 6g/mL

What is the exact molar mass of Fe? Hint: Not the rounded mass

• 26 g/mole
• 55.845 g/mole

• 55 g/mole

• 6.02 x 10²³ g/mole

What is the molar mass of fluorine gas, F₂?

• 18.998 g/mol
• 38 g/mol
• 9 g/mol
• 18 g/mol

What is the molar mass of MgCl₂?

• 24.31 g/ml
• 95.21 g/mol
• 59.76 g/mol
• 70.90 g/mol

Which of the following is considered an empirical formula?

• CH₃COOH
• C₆H₁₂O₆
• H₂O

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆