% Composition of compound

 

What is the general formula for the computation of percentage composition of the given element?

• a. % mass of element = mass of element in the compound divided by mass of the compound times 100

• b. % mass of element = mass of element in the compound divided by mass of the compound

• c. % mass of element = mass of element in the compound divided by 100

• d. % mass of element = mass of element in the compound

What is the percent by mass of magnesium in MgO?

• a. 20%

• b. 40%

• c. 50%

• d. 60%

What is the percent by mass of chlorine in NaCl?

• a. 39%

• b. 61%

• c. 35%

• d. 36%

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• a. 24%

• b. 48%

• c. 49%

• d. 65%

What is the percent by mass of calcium in CaF₂ (gram-formula mass = 78 g/mol)?

• a. 24%

• b. 49%

• c. 51%

• d. 65%

What is the percent composition of Benzene, C₆H₆?

• a. C = 50%

  H = 50%

• b. C = 85.7 %

  H = 14.3%

• c. C = 92.2%

  H = 7.8%

• d. C = 71.9%

  H = 28.1%

Which element in the compound potassium cyanide, KCN, has a percent composition of 60.97%?

• a. K

• b. C

• c. N

• d. None

What is the mass of one mole of aluminum chloride (remember to determine the correct formula first)?

• a. 62.435g

• b. 116.399g

• c. 133.341g

• d. 97.888g

 

What is the molar mass of PbSO₄

• a. 303.3 g/mol

• b. 294.7g/mol

• c. 163.8g/mol

• d. 372g/mol

How many hydrogen atoms are in one formula unit of C₂H₄O₂?

• a. 2

• b. 1

• c. 4

• d. 6