$A$ sample of calcium carbonate $(CaCO_3)$ has the following percentage composition: $Ca = 40\%$,$C = 12\%$,$O = 48\%$. If the Law of Definite Proportions is true,what is the weight of calcium in a $4 \ g$ sample of calcium carbonate?

$1.7 \, g$ of silver nitrate is dissolved in $100 \, g$ of water. Another $0.585 \, g$ of sodium chloride is dissolved in $100 \, g$ of water and added to the first solution,resulting in a chemical reaction. $1.435 \, g$ of silver chloride and $0.85 \, g$ of sodium nitrate are produced. Which law is followed by the above information?

$A$ sample of pure carbon dioxide,irrespective of its source,contains $27.27\%$ carbon and $72.73\%$ oxygen. This data supports:

$A$ chemical equation is balanced according to the law of

Which of the following pairs of compounds cannot demonstrate the law of multiple proportions?

Atoms combine in chemical reactions to form: