Solution (1)
Step 1: Calculate the molar mass of Na₂S.
molar mass = (22.99 g/mol × 2) + (32.07 g/mol × 1)
molar mass = 78.05 g/mol
Step 2: Calculate the percentage composition of Na in Na₂S.
[tex]\text{mass percent of Na} = \frac{\text{22.99 g/mol × 2}}{\text{78.05 g/mol}} × 100[/tex]
[tex]\boxed{\text{mass percent of Na = 58.91\%}}[/tex]
Solution (2)
Step 1: Calculate the molar mass of Fe(OH)₂.
molar mass = (55.85 g/mol × 1) + (16.00 g/mol × 2) + (1.008 g/mol × 2)
molar mass = 89.87 g/mol
Step 2: Calculate the percentage composition of O in Fe(OH)₂.
[tex]\text{mass percent of O} = \frac{\text{16.00 g/mol × 2}}{\text{89.87 g/mol}} × 100[/tex]
[tex]\boxed{\text{mass percent of O = 35.61\%}}[/tex]
Solution (3)
Step 1: Calculate the molar mass of CaSO₄.
molar mass = (40.08 g/mol × 1) + (32.07 g/mol × 1) + (16.00 g/mol × 4)
molar mass = 136.15 g/mol
Step 2: Calculate the percentage composition of Ca in CaSO₄.
[tex]\text{mass percent of Ca} = \frac{\text{40.08 g/mol × 1}}{\text{136.15 g/mol}} × 100[/tex]
[tex]\boxed{\text{mass percent of Ca = 29.44\%}}[/tex]
Solution (4)
Step 1: Calculate the molar mass of Al(HCO₃)₃.
molar mass = (26.98 g/mol × 1) + (1.008 g/mol × 3) + (12.01 g/mol × 3) + (16.00 g/mol × 9)
molar mass = 210.03 g/mol
Step 2: Calculate the percentage composition of H in Al(HCO₃)₃.
[tex]\text{mass percent of H} = \frac{\text{1.008 g/mol × 3}}{\text{210.03 g/mol}} × 100[/tex]
[tex]\boxed{\text{mass percent of H = 1.44\%}}[/tex]
Solution (5)
Step 1: Calculate the molar mass of Zn(ClO₂)₂.
molar mass = (65.39 g/mol × 1) + (35.45 g/mol × 2) + (16.00 g/mol × 4)
molar mass = 200.29 g/mol
Step 2: Calculate the percentage composition of O in Zn(ClO₂)₂.
[tex]\text{mass percent of O} = \frac{\text{16.00 g/mol × 4}}{\text{200.29 g/mol}} × 100[/tex]
[tex]\boxed{\text{mass percent of O = 31.95\%}}[/tex]
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