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05 Definite proportions and % composition

Last updated over 4 years ago
13 questions
When show your work is available, 1 pt answer, 1 pt work. Although if you enter the right answer, it will show both points, 1 will be deducted if work isn't shown. Also, make sure to use weights to the tenth, not the hundreth or your answers will be incorrect. Answers will be to the tenth.

1. Calculate the molar mass of the compound
2. Divide the contributed mass of each element by the total molar mass (this should be a decimal since the part is smaller than the whole).
3. Multiply by 100 (that is how you calculate the percent, or part of 100)
2

Calculate the percent composition of: PbO2
To enter answer, use this format: x% Element 1; y% Element 2; x% Pb; y% O

2

Calculate the percent composition of: (CH3)2CO
To enter answer, use this format: x% Element 1; y% Element 2; z% Element 3

2

Calculate the percent composition of: KIO3
To enter answer, use this format: x% Element 1; y% Element 2; z% Element 3

2

Calculate the percent composition of: HBrO4
To enter answer, use this format: x% Element 1; y% Element 2; z% Element 3

Using percent composition
2

Water is always 11.19% hydrogen and 88.81% oxygen by mass. Calculate the mass of hydrogen and the mass of oxygen in 1000 grams of water.

2

Water is always 11.19% hydrogen and 88.81% oxygen by mass. Calculate the mass of hydrogen and the mass of oxygen in 723.65 grams of water.

2

Water is always 11.19% hydrogen and 88.81% oxygen by mass. Calculate the mass of hydrogen and the mass of oxygen in 32 kg of water.

2

Water is always 11.19% hydrogen and 88.81% oxygen by mass. Why can't we calculate the mass of hydrogen and the mass of oxygen in 24,000 gallons of water? What other information would we need?

2

Copper oxide is always 79.85% copper and 20.15% oxygen by mass. Calculate the mass of copper and the mass of oxygen in 1000 grams of copper oxide.

2

How many grams of lead are in a 63.8 g sample of PbO2? Use the values calculated in problem 1.

2

How many grams of oxygen are in a 36.8 g sample of KIO3? Use the values calculated in problem 3.

2

A fertilizer is advertised as containing 15.8% nitrogen (by mass). How many kilograms of nitrogen is in a 4.15 kg sample of the fertilizer?

4

Which contains more carbon, 4.71 g of glucose, C6H12O6, or 4.25 g ethanol, C2H6O? How much more?