When converting from grams of a formula to moles of a formula, you will use (a.), but when converting from of a formula to moles of a constituent element, you will use (b.).

• (a.) formula molar mass, (b.) formula subscripts
• (a.) Avogadro's number, (b.) formula molar mass
• (a.) formula molar mass, (b.) element molar mass

Calculate how many moles of H are in 1.73 moles of (NH₄)₂SO₄.

• 13.8 mol H
• 6.92 mol H
• 3.46 mol H
• 8.12 mol H

What did the student do wrong with the following set-up for the conversion of 2.85 g H to g of H₂O?

• The student used an incorrect atom to formula ratio
• The student calculated the wrong molar mass for water, H₂O.
• The student has the correct set-up, but calculated incorrectly.
• The student placed the molar mass in the wrong position.

What mass, in grams, of F are in 149 g of SF₆?

• 116 g F
• 136 g F
• 121 g F
• 78.4 g F

What is the empirical formula of C₆H₁₂O₃?

• C₂H₄O
• C₃H₆O
• C₃H₆O₂
• C₂H₆O

What is the empirical formula of N₂O?

• N₂O
• NO
• NO₂
• N₄O₂

What did the student do wrong with the following set-up for the calculation of the empirical formula?

• The student forgot to convert mass in grams to moles.
• The student has the correct set-up, but calculated incorrectly.
• The student did not divide by the smallest quantity.
• The student should have multiplied by 5 to get the smallest whole number subscript in the final formula.

Find the empirical formula of a compound whose percent composition is 52.14% C, 13.13% H, and 34.73% O.

• C₂H₆O
• C₁₂H₃O₈
• C₄HO₃
• C₆H₄O

Which of the following is the correct set-up for a percent calculation?

• 
• 
• 
• 

Calculate the percent sulfur in sulfur trioxide, SO₃.

• 40.04% S
• 30.08% S
• 25.07% S
• 64.89% S