Final answer:
The correct statements consistent with the law of constant composition are that each sample of calcium sulfide always has 44.4% calcium by mass, the mass ratio of calcium to sulfur is always 1.25, and the sum of the mass percentages of calcium and sulfur equals 100%.
Step-by-step explanation:
The law of constant composition (also known as the law of definite proportions) states that a chemical compound always contains exactly the same proportion of elements by mass. Therefore, consistent with this law:
- (a) Every sample of calcium sulfide will have 44.4% mass of calcium is correct because the proportion of mass of calcium to the total mass of the compound is constant.
- (c) The mass ratio of Ca to S in every sample of calcium sulfide is 1.25, which is calculated by dividing the mass of calcium (4.61g) by the mass of sulfur (3.68g), is also correct.
- (e) The mass percentage of calcium plus the mass percentage of sulfur in every sample of calcium sulfide equals 100% is correct, as the sum of the mass percentages of the elements in a compound must always equal 100%.
The options b and d are incorrect. The amount of calcium in grams (2.86 g) will vary depending on the size of the sample (b), and the ratio of elements in a compound does not change based on how the sample was prepared (d).