IGCSE CHEMISTRY (moles, molecular, empirical formula)

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

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

•  NaPO2
• Na2PO3
• Na3PO4
• NaPO4

What is the empirical formula if you have 81.82% carbon and 18.18% hydrogen?

• C3H8
• CH4
• C2H2
• C4H10

What is the percent composition by mass of sulfur in the compound MgSO₄ (molar mass = 120 g/mol)?

• 20%

• 27%

• 46%

• 53%

What is the empirical formula if you have 88.80% copper and 11.20% oxygen?

• Cu₃O₈
• CuO₄
• Cu₂O
• Cu₄O₁₀

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 120?

• CH₂O

• C₂H₄O₂

• C₄H₈O₄

• C₆H₁₂O₆

Which of the following represents an empirical formula?

• H₂O₂
• HC₂O₄
• H₂O₆
• H₁₂O₄₈

What are the units for molar mass?

• grams
• amu
• grams/mole
• liters

Find the percentage composition of  Mg in Mg₃(PO₄)₂.
   

• 27.75% Mg
• 23.57% Mg
• 48.68% Mg
• 13.45% Mg

Tags

NGSS.HS-PS1-7

Find the percent composition of each element in N₂S₂ .

• 69.6% N, 30.4%S
• 15.2% N, 84.8% S
• 30.4% N, 69.6% S
• 65.2% N, 34.8% S