Find the percent composition of each element in:a) Ethanol C2 H6 Ob) Potassium sulfite

a) Ethanol (C2H6O)

Step 1: Find the molar mass of each element in the compound.

• Carbon (C): 12.01 g/mol
• Hydrogen (H): 1.008 g/mol
• Oxygen (O): 16.00 g/mol

Step 2: Multiply the molar mass of each element by the number of atoms of that element in the compound.

• Carbon: 12.01 g/mol x 2 = 24.02 g/mol
• Hydrogen: 1.008 g/mol x 6 = 6.048 g/mol
• Oxygen: 16.00 g/mol x 1 = 16.00 g/mol

Step 3: Add up the total molar mass of the compound. 24.02 g/mol + 6.048 g/mol + 16.00 g/mol = 46.068 g/mol

Step 4: Divide the total molar mass of each element by the total molar mass of the compound and multiply by 100 to get the percent composition.

• Carbon: (24.02 g/mol ÷ 46.068 g/mol) x 100 = 52.14%
• Hydrogen: (6.048 g/mol ÷ 46.068 g/mol) x 100 = 13.13%
• Oxygen: (16.00 g/mol ÷ 46.068 g/mol) x 100 = 34.73%

b) Potassium sulfite (K2SO3)

Step 1: Find the molar mass of each element in the compound.

• Potassium (K): 39.10 g/mol
• Sulfur (S): 32.06 g/mol
• Oxygen (O): 16.00 g/mol

Step 2: Multiply the molar mass of each element by the number of atoms of that element in the compound.

• Potassium: 39.10 g/mol x 2 = 78.20 g/mol
• Sulfur: 32.06 g/mol x 1 = 32.06 g/mol
• Oxygen: 16.00 g/mol x 3 = 48.00 g/mol

Step 3: Add up the total molar mass of the compound. 78.20 g/mol + 32.06 g/mol + 48.00 g/mol = 158.26 g/mol

Step 4: Divide the total molar mass of each element by the total molar mass of the compound and multiply by 100 to get the percent composition.

• Potassium: (78.20 g/mol ÷ 158.26 g/mol) x 100 = 49.39%
• Sulfur: (32.06 g/mol ÷ 158.26 g/mol) x 100 = 20.26%
• Oxygen: (48.00 g/mol ÷ 158.26 g/mol) x 100 = 30.35%