Empirical formulas Knowledge-Based Download PDF

Questions

1. 1.

   A 2.16 g sample of a hydrocarbon is completely burned in excess oxygen to produce 7.04 g of $\text{CO}_2$ and 2.16 g of $\text{H}_2\text{O}$. What is the empirical formula of the hydrocarbon? (Molar masses: $\text{C} = 12.0\text{ g/mol}$, $\text{H} = 1.0\text{ g/mol}$, $\text{O} = 16.0\text{ g/mol}$)

   • A) $\text{CH}_2$
   • B) $\text{C}_2\text{H}_3$
   • C) $\text{C}_3\text{H}_8$
   • D) $\text{C}_4\text{H}_3$
2. 2.

   A mineral sample contains 32.4% sodium, 22.6% sulfur, and 45.0% oxygen by mass. What is the empirical formula of this compound? (Molar masses: Na = 23.0 g/mol, S = 32.1 g/mol, O = 16.0 g/mol)

   • A) NaSO4
   • B) Na2SO4
   • C) Na2SO3
   • D) NaSO2
3. 3.

   A 4.79 g sample of titanium reacts completely with chlorine gas to produce 18.99 g of a titanium chloride compound. What is the empirical formula of this compound? (Molar masses: Ti = 47.9 g/mol, Cl = 35.5 g/mol)

   • A) $\text{TiCl}_3$
   • B) $\text{TiCl}_4$
   • C) $\text{TiCl}_2$
   • D) $\text{Ti}_2\text{Cl}_5$
4. 4.

   A 4.60 g sample of a compound containing only carbon, hydrogen, and oxygen contains 2.40 g of carbon and 0.60 g of hydrogen. What is the empirical formula of this compound? (Molar masses: C = 12.0 g/mol, H = 1.0 g/mol, O = 16.0 g/mol)

   • A) $\text{C}_2\text{H}_6\text{O}$
   • B) $\text{CH}_3\text{O}$
   • C) $\text{CH}_2\text{O}$
   • D) $\text{C}_2\text{H}_4\text{O}$
5. 5.

   A sample of an iron oxide contains 69.9% iron and 30.1% oxygen by mass. What is the empirical formula of this compound? (Molar masses: Fe = 55.8 g/mol, O = 16.0 g/mol)

   • A) $\text{Fe}_2\text{O}_3$
   • B) $\text{FeO}$
   • C) $\text{Fe}_3\text{O}_4$
   • D) $\text{FeO}_2$