1. Calculate the number of oxygen atoms in 10g of H2SO4. 2. Calculate the number of moles in the following substances. 3. What is the relative mass of PbCO3?

Steps to Solve

1. Calculate the molar mass of H₂SO₄

The molar mass of a compound is the sum of the atomic masses of each element in the compound, multiplied by the number of times that element appears in the compound. Molar mass of Hydrogen (H) = 1 g/mol Molar mass of Sulfur (S) = 32 g/mol Molar mass of Oxygen (O) = 16 g/mol

Molar mass of H₂SO₄ = $2 \cdot 1 + 1 \cdot 32 + 4 \cdot 16 = 2 + 32 + 64 = 98$ g/mol

2. Calculate the number of moles of H₂SO₄ in 10g

To find number of moles, we divide the given mass by the molar mass

Number of moles = $\frac{Given \ mass}{Molar \ mass}$ Number of moles of H₂SO₄ = $\frac{10}{98} \approx 0.102$ moles

3. Calculate the number of molecules of H₂SO₄

To find the number of molecules, we multiply number of moles by Avogadro's number ($6.022 \cdot 10^{23}$)

Number of molecules = Number of moles $\cdot$ Avogadro's number Number of molecules of H₂SO₄ = $0.102 \cdot 6.022 \cdot 10^{23} \approx 0.614 \cdot 10^{23}$ molecules

4. Calculate the number of oxygen atoms

Each molecule of H₂SO₄ has 4 oxygen atoms

Number of oxygen atoms = Number of molecules of H₂SO₄ $\cdot$ 4 Number of oxygen atoms = $0.614 \cdot 10^{23} \cdot 4 = 2.456 \cdot 10^{23}$ atoms