3.1 Formula Mass and the Mole Concept

What is the total mass (amu) of carbon in each of the following molecules?

(a) CH₄

(b) CHCl₃

(c) C₁₂H₁₀O₆

(d) CH₃CH₂CH₂CH₂CH₃

Calculate the molecular or formula mass of each of the following:

(a) P₄

(b) H₂O

(c) Ca(NO₃)₂

(d) CH₃CO₂H (acetic acid)

(e) C₁₂H₂₂O₁₁ (sucrose, cane sugar)

Write a sentence that describes how to determine the number of moles of a compound in a known mass of the compound using its molecular formula.

Which contains the greatest mass of oxygen: 0.75 mol of ethanol (C₂H₅OH), 0.60 mol of formic acid (HCO₂H), or 1.0 mol of water (H₂O)? Explain why.

How are the molecular mass and the molar mass of a compound similar and how are they different?

Calculate the molar mass of each of the following:

(a) S₈

(b) C₅H₁₂

(c) Sc₂(SO₄)₃

(d) CH₃COCH₃ (acetone)

(e) C₆H₁₂O₆ (glucose)

Calculate the molar mass of each of the following:

(a) the anesthetic halothane, C₂HBrClF₃

(b) the herbicide paraquat, C₁₂H₁₄N₂Cl₂

(c) caffeine, C₈H₁₀N₄O₂

(d) urea, CO(NH₂)₂

(e) a typical soap, C₁₇H₃₅CO₂Na

Determine the mass of each of the following:

(a) 0.0146 mol KOH

(b) 10.2 mol ethane, C₂H₆

(c) 1.6 $\times$ 10⁻³ mol Na₂ SO₄

(d) 6.854 $\times$ 10³ mol glucose, C₆ H₁₂ O₆

(e) 2.86 mol Co(NH₃)₆Cl₃

Determine the mass of each of the following:

(a) 2.345 mol LiCl

(b) 0.0872 mol acetylene, C₂H₂

(c) 3.3 $\times$ 10⁻² mol Na₂CO₃

(d) 1.23 $\times$ 10³ mol fructose, C₆H₁₂O₆

(e) 0.5758 mol FeSO₄(H₂O)₇

Determine the mass in grams of each of the following:

(a) 0.600 mol of oxygen atoms

(b) 0.600 mol of oxygen molecules, O₂

(c) 0.600 mol of ozone molecules, O₃

Determine the number of atoms and the mass of zirconium, silicon, and oxygen found in 0.3384 mol of zircon, ZrSiO₄, a semiprecious stone.

Determine which of the following contains the greatest mass of aluminum: 122 g of AlPO₄, 266 g of Al₂Cl₆, or 225 g of Al₂S₃.

The Cullinan diamond was the largest natural diamond ever found (January 25, 1905). It weighed 3104 carats (1 carat = 200 mg). How many carbon atoms were present in the stone?

A certain nut crunch cereal contains 11.0 grams of sugar (sucrose, C₁₂H₂₂O₁₁) per serving size of 60.0 grams. How many servings of this cereal must be eaten to consume 0.0278 moles of sugar?

Which of the following represents the least number of molecules?

(a) 20.0 g of H₂O (18.02 g/mol)

(b) 77.0 g of CH₄ (16.06 g/mol)

(c) 68.0 g of C₃H₆ (42.08 g/mol)

(d) 100.0 g of N₂O (44.02 g/mol)

(e) 84.0 g of HF (20.01 g/mol)