Moles and Avogadro's Numbers

4.6 g Na = 0.2 mol. From the equation, 2 mol Na produce 1 mol H₂. Hence 0.2 mol Na produces 0.1 mol H₂.

Equal coefficients indicate equal numbers of moles.

Benzene contains six carbon atoms per molecule.

One mole methane requires two moles oxygen. Therefore, oxygen required is 64 g.

Twelve moles of water react with one mole Al₄C₃. Twelve × 18 = 216 g.

Molecular formula becomes C₆H₁₂O₆, containing twelve hydrogen atoms.

Gas volumes follow mole ratios. Hydrogen volume is three times nitrogen volume.

One mole pentane forms eleven moles of gaseous products. One-quarter mole forms 2.75 moles.

Nineteen grams correspond to 0.25 mole CS₂. This produces 0.5 mole SO₂ having a mass of 32 g.

One formula unit produces five ions. Therefore, 0.1 mole gives 0.5 mole of ions, equal to 3.011 × 10²³ ions.

4.6 g Na equals 0.2 mole. According to the equation, 2 moles Na produce 1 mole H₂. Thus, 0.2 mole Na produces 0.1 mole H₂.

Multiplying the mass of one atom by Avogadro's number gives approximately 16 g mol⁻¹.

Every molecule contains four chlorine atoms. Therefore, 0.5 mole CCl₄ contains 2 moles of chlorine atoms.

One mole H₂S produces 1.5 moles sulfur. The mass becomes 1.5 × 32 = 48 g.

The sample contains 0.25 mole urea. With molar mass 60 g mol⁻¹, the mass equals 15 g.

Ten grams correspond to 0.1 mole CaCO₃, producing 0.1 mole CO₂ occupying 2.24 dm³ at STP.

One mole of phosphorus molecules requires five moles of oxygen. Therefore, 0.25 mole requires 1.25 moles.

OH⁻ contains eight electrons from oxygen, one from hydrogen, and one extra electron due to the negative charge.

The ratio of H₂O to CO₂ is 3:2. Therefore, 3 moles of CO₂ correspond to 4.5 moles of H₂O.