Stoichiometry

An element $X$ has a relative atomic mass of 4. How much heavier is one atom of element $X$ compared to $1/12^{th}$ of the mass of a carbon-12 atom?

Calculate the relative formula mass ($M_r$) of calcium carbonate, $CaCO_3$. (Given $A_r$: $Ca=40, C=12, O=16$)

What is the relative molecular mass ($M_r$) of ethanol, $C_2H_5OH$? (Given $A_r$: $C=12, H=1, O=16$)

Which of the following constants represents the number of particles in exactly one mole of a substance?

At Room Temperature and Pressure (RTP), what is the volume occupied by 2.5 moles of Helium gas? (Molar gas volume at RTP = $24\ dm^{3}/mol$)

How many moles are present in 18 g of water ($H_{2}O$)? (Relative atomic masses: $H = 1, O = 16$)

Which of the following molecular formulae is also an empirical formula?

A hydrocarbon compound consists of $80\%$ carbon and $20\%$ hydrogen by mass. Given the relative atomic masses ($A_{r}: C=12, H=1$), what is its empirical formula?

Glucose has the molecular formula $C_{6}H_{12}O_{6}$. What is the empirical formula of glucose?

What is the relative formula mass ($M_r$) of copper(II) sulfate pentahydrate, $CuSO_4 \cdot 5H_2O$? (Relative atomic masses: $Cu=64, S=32, O=16, H=1$)

In the reaction $N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)$, what volume of hydrogen is required to react completely with $10\,cm^3$ of nitrogen?

A balloon contains $48.0\,dm^3$ of $NH_3$ gas at room temperature and pressure (RTP). How many moles of gas are present? (Molar volume at RTP = $24.0\,dm^3/mol$)