determine the percentage by mass of calcium in calcium carbonate (ca=40).
Answers
The law of constant proportions states that the chemical compounds are made up of elements that are present in a fixed ratio by mass. This means that a pure sample of a compound, no matter what the source is, will always contain the same elements that are present in the same ratio by mass. Let us now use this law to find the weight of the calcium in 4 g of calcium carbonate.
The percentage compositions of the elements of calcium carbonate are given as: Ca = 40%; C = 12%; O = 48%. As it is also given that the law of constant proportion holds true, then this means that even the sample of 4g of calcium carbonate will have the percentage composition of the constituent elements as: Ca = 40%; C = 12%; O = 48%.
Therefore, this means that 100g of CaCO3, 40 g of Ca is present.
Thus, in a 4g sample of CaCO3, let x g of Ca be present.
This means, x4=40100
⟹x=40×x100
⟹x=1.6g
Therefore, the weight of calcium in 4 g of a sample calcium carbonate from another source is 1.6g.
Answer:
40%
Explanation:
Molecular mass of CaCO3 = 40+12+3×16=100 amu
Mass of calcium in 1 mole of CaCO3 = 40 gm
Percentage of calcium = (40×100)÷100 = 40%