Math of Chem

If I have 23.5 grams of sulfur, how many moles doe I have?

• 0.73 moles

• 1.36 moles

• 753.4 moles

• 6.023X10²³ moles

Which answer represents an empirical formula and a molecular formula?

• N₂O₄ and C₆H₁₂O₆

• H₂O and NO

• HO and H₂O₂

• SO₄ and HCl

Consider the balanced equation below:

6 CO₂ + 6 H₂O ---> C₆H₁₂O₆ + 6 O₂

If 9 moles of CO₂ are used, how many moles of C₆H₁₂O₆ will be formed?

• 6 moles

• 1.5 moles

• 1 mole

• 3 moles

What is the percent composition by mass of nitrogen in the compound N₂H₄ (gram formula mass 32.0 g/mol)

• 13%

• 44%

• 88%

• 93%

A 8.0 gram sample of hydrated copper sulfate was heated to a constant mass. The final mass of the anhydrous salt was 5.12 g. What is the percent composition by mass of copper sulfate hydrate?

• 64%

• 45%

• 25 %

• 36%

What is the gram formula mass of Ca(OH)₂?

• 74.1 g

• 114.2 g

• 57.1 g

• 46.0 g

What is the mole ratio of nitrogen to ammonia (NH₃) in the balanced equation:

N₂ + 3H₂ ------> 2NH₃

• 3:2

• 2:3

• 2:1

• 1:2

A compound has the empirical formula SO and a molar mass of 144 g. What is its molecular formula?

• S₂O₂

• SO

• S₃O₃

• S₄O₄

How many moles of oxygen atoms are in ammonium carbonate?

• 3 moles

• 1 mole

• 6.023 X 10²³ moles

• 4 moles

What is the percent composition by mass of water in CuSO₄*5H₂O?

• 7.0%

• 36.1%

• 23.5%

• 42.3%