Question

A 4.77g sample of calcium sulfide was decomposed into its constituent elements, producing 2.65g of calcium and 2.12g of sulfur. Which of the following statements are consistent with the law of constant composition. select all that apply.
A. the mass ratio of s to ca in every sample of calcium sulfide is 0.80.
b. every sample of calcim sulfide will have 2.65g of calcium.
c.the mass % of calcium plus the mass % of sulfur in every sample of calcium slfide equals 100%.
D. the ratio of ca to s will vary on how the sample was prepared.
E. every sample of calcium sulfide will have 44.4% mass of sulfir.

Answer 1

We have calcium sulfide decomposing into calcium and sulfur atoms

CaS ------------> Ca + S

4.77g 2.65g 2.12g

A) correct mass of S to Ca = 2.12g/2.65g = 0.8

B) correct law of constant composition says that any molecule is formed from a definite ration of its constituents

C) correct ,total mass of a molecule is conserved and equal to sum of mass of individual atoms

D) False , Law of constant composition says a molecule has a definite mass regardless of its source

E) correct 2.12g/4.77g x 100 = 44.44 %