Chemical Comp Review

Which pair has the same empirical formula?

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

Which formula is an empirical formula?

• H₂O₂

• C₂H₆O₁₂

• CaCl₂

• N₂O₈

What is the percent by mass of sodium in NaCl?

• 39%
• 61%
• 35%
• 65%

Fluorine is diatomic.  What is the molar mass of fluorine gas?

• 18.998 g/mol
• 37.996 g/mol
• 9 g/mol
• 18 g/mol

*How many grams are in 1.2 x 10²⁴ atoms of C?

• 28 grams

• 24 grams

• 6.02 grams

• 1.2 grams

*What is the molar mass of B₂(CO₃)₃?

• 81.6 g/mol

• 94.8 g/mol

• 38.8 g/mol

• 201.6 g/mol

*How many moles are in 3.01 x 10²² atoms of magnesium?

• 0.05 moles

• 1.81 x 10⁴⁶ moles

• 5.00 x 10²¹ moles

• 5.00 moles

*Find the percent composition of N₂S₂.

• N: 69.6% S: 30.4%

• N:36% S: 75.6%

• N: 96.6% S: 3.4%

• N: 30.4% S: 69.6%

*You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements. (keep two decimal places throughout calculations)

• SO

• SO₂

• SO₃

• SO₄

*What is the total number of atoms contained in 80 grams of neon?

• 6.02 x 10²³

• 1.2 x 10²⁴

• 2.4 x 10²⁴

• 4.8 x 10²⁴