Unit 9 Review

Mole Conversions

100

How many moles are equal to 1.30 x 10²⁴ atoms of sulfur?

2.16 mol S

200

How many particles are equal to 0.625 moles of helium?

3.76 x 10²³ particles He

300

What volume would 0.453 moles of hydrogen gas (H₂) occupy at STP?

10.1 L H₂

400

How many moles are there in 34 grams of Cu(OH)₂?

0.35 mol Cu(OH)₂

500

How many grams are equal to 0.624 moles of NaCl?

36.5 g NaCl

Mole Conversions

100

How much do 7.40 x 10²³ molecules of AgNO₃ weigh?

209 g AgNO₃

200

How many molecules are present in 230 grams of CoCl₂?

1.1 x 10²⁴ molecules CoCl₂

300

What is the mass of 7.72 x 10²³ atoms of Fe₂SO₄?

266 g Fe₂SO₄

400

What is the volume of 2.22 x 10²³ molecules of sulfur?

8.26 L S

500

How many molecules of OF₂ would have a volume of 11.2 L?

3.01 x 10²³ molecules OF₂

Percent Composition

100

What is the % O in Li₂O?

53.55% O

200

What is the % N in Ba(NO₃)₂?

10.72% N

300

What is the % C in Ca(C₂H₃O₂)₂?

30.37% C

400

What is the percent composition of the elements in Fe₃O₄?

72.360% Fe

27.64% O

500

What is the percent composition of the elements in (NH₄)₂SO₄?

21.20% N

6.102% H

24.27% S

48.43% O

Empirical Formula

100

Find the empirical formula of a compound consisting of 53.7% iron and 46.3% sulfur

Fe₂S₃

200

An acid commonly used in the automotive industry is shown to be 3.1% hydrogen, 31.6% phosphorous, and 63.5% oxygen. Determine the empirical formula of this acid.

H₃PO₄

300

Find the empirical formula for a compound containing 72.7% magnesium and 27.8% nitrogen.

Mg₃N₂

400

A compound is composed of 27.3g aluminum, 48.1g sulfur, and 96.64g oxygen. Determine its empirical formula.

Al₂S₃O₁₂

500

Find the empirical formula for a compound containing 26.56% potassium, 35.41% chromium, and the remainder oxygen.

K₂Cr₂O₇

Molecular Formula

100

A compound with an empirical formula of С₄H₄O and a molar mass of 136 grams per mole. What is the molecular formula of this compound?

C₈H₈O₂

200

A compound with an empirical formula of CFBrO and a molar mass of 254.7 grams per mole. What is the molecular formula of this compound?

C₂F₂Br₂O₂

300

What is the molecular formula of a compound composed of 25.9% nitrogen and 74.1% oxygen with a molecular mass of 324 amu?

N₆O₁₅

400

A compound is 64.9% carbon, 13.9% hydrogen, and 21.6% oxygen. Its molecular mass is 75 g/mol. What is its molecular formula?

C₄H₁₀O

500

A compound containing 5.9265% H and 94.0735% O has a molar mass of 34.01468 g/mol. Determine the molecular formula of this compound.

H₂O₂