A sample of hydrated copper sulfate weighs 25g. After heating to remove the water of crystallization, the anhydrous copper sulfate weighs 16g. What is the percentage of water of crystallization in the original sample?

If two elements A and B combine in different ratios to form two compounds, $A_xB_y$ and $A_pB_q$, then according to the Law of Multiple Proportions:

Two elements, X and Y, combine to form two compounds. Compound A contains 27.3% X and 72.7% Y by mass. Compound B contains 42.9% X and 57.1% Y by mass. If the mass of Y is fixed at 100g in both compounds, which of the following represents the masses of X in the two compounds, consistent with the Law of Multiple Proportions?

If two elements A and B combine in different ratios to form two compounds, the masses of B that combine with a fixed mass of A are in a small whole number ratio. This is a statement of:

Two elements X and Y combine to form two compounds $XY_2$ and $X_2Y_3$. If 0.05 moles of $XY_2$ weighs 5 g and 0.10 moles of $X_2Y_3$ weighs 20 g, find the atomic masses of X and Y.

If two elements A and B combine to form two compounds AB and AB2, and 1g of A combines with 0.5g of B in AB, how much of B will combine with 1g of A in AB2 according to the Law of Multiple Proportions?