Ch. 7 Formula Math

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃
• MgN₂
• Mg₃N₂ 
• MgN

Which of the following is considered an empirical formula?

• CH₃COOH
• C₆H₁₂O₆
• H₂O

How many molecules are in 2.5 mol of NaCl?

• 1.5 x 10²⁴ molecules

• 1.5 molecules

• 4.15 molecules

• 1.5 x 10²³ molecules

Which pair has the same empirical formula?

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

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

• C₂H₃O₂
• CH₂O
• C₂H₄O₂
• C₃H₈O₃

What is the empirical formula for C₄H₆?

• CH

• CH₃

• C₂H₃

• C₄H₆

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

• SO

• SO₂

• SO₃

• SO₄

What is the empirical formula for N₂S₃?

• NS

• N₃S₂

• N₂S₃

• N₁S_1.5

Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.

• NaPO₂

• Na₂PO₃

• Na₃PO₄

• NaPO₄

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

What is the percent by mass of oxygen in MgO?

• 20%
• 40%
• 50%
• 60%

Tags

NGSS.HS-PS1-7