Stoichiometry

Relative Atomic Mass is defined as the average mass of the atoms of an element compared to:

Calculate the relative molecular mass ($M_r$) of sulfuric acid, $H_2SO_4$. (Given $A_r$: $H=1, S=32, O=16$)

What is the relative molecular mass ($M_r$) of sulfur hexafluoride, $SF_6$? (Given $A_r$: $S=32, F=19$)

Determine the relative molecular mass ($M_r$) of silicon dioxide, $SiO_2$. (Given $A_r$: $Si=28, O=16$)

Determine the relative formula mass of hydrated aluminum sulfate, $Al_2(SO_4)_3 \cdot 18H_2O$. (Given $A_r$: $Al=27, S=32, O=16, H=1$)

What is the percentage by mass of fluorine in sulfur hexafluoride, $SF_6$? (Given $A_r$: $S=32, F=19$)

What is the difference in relative molecular mass ($M_r$) between heavy water ($D_2O$) and normal water ($H_2O$)? (Given $A_r$: $H=1, D=2, O=16$)

A 5.0 g sample of an alloy of gold and copper is treated with nitric acid. The copper dissolves, and 3.8 g of gold remains. What is the percentage of copper in the alloy?

A sample of air contains 21% oxygen and 79% nitrogen by volume. What is the average relative molecular mass of air? ($M_r: O_2=32, N_2=28$)

If 0.2 mol of a compound $X$ has a mass of 32 g, and $X$ contains 50% element $A$ ($A_r=40$) by mass, how many atoms of $A$ are in one molecule of $X$?

How many moles are in 2.2 g of Carbon Dioxide? (Relative formula mass: $CO_{2} = 44$)

What is the mass of 0.25 moles of Magnesium? (Relative atomic mass: $Mg = 24$)

Which formula relates moles, concentration, and volume of a solution?

What is the volume of 10 moles of gas at RTP in $dm^{3}$?

A container holds $3.01 \times 10^{23}$ molecules of $SO_{2}$. What is the mass of the gas? ($S = 32, O = 16$)

If $0.5\ mol$ of a gas occupies $11.2\ dm^{3}$ at a certain temperature and pressure, what volume will $2.0\ mol$ of the gas occupy under the same conditions?

What is the mass of Calcium needed to react with $12\ dm^{3}$ of Oxygen at RTP to form Calcium Oxide? ($Ca = 40, O = 16$)

A $0.150\ g$ sample of a metal $M$ was added to $50.0\ cm^{3}$ of $0.100\ mol/dm^{3}$ silver nitrate ($AgNO_{3}$) solution. The metal reacted completely according to the equation: $M (s) + 2Ag^{+} (aq) \rightarrow M^{2+} (aq) + 2Ag (s)$. After the reaction was complete, the excess silver ions in the resulting solution were titrated with $0.080\ mol/dm^{3}$ potassium thiocyanate ($KSCN$). The titration required $12.5\ cm^{3}$ of the $KSCN$ solution to reach the endpoint: $Ag^{+} (aq) + SCN^{-} (aq) \rightarrow AgSCN (s)$. What is the relative atomic mass ($A_{r}$) of metal $M$?

$0.10\ mol$ of a hydrocarbon $C_{n}H_{2n}$ requires $0.60\ mol$ of $O_{2}$ for complete combustion. What is the value of $n$?

A gas mixture contains $50\%$ $CH_{4}$ and $50\%$ $C_{2}H_{6}$ by volume. What is the total volume of $O_{2}$ required for the complete combustion of $20\ cm^3$ of this mixture?

A compound has an empirical formula of $CH_{2}$. Its molecular mass is 28. What is its molecular formula? ($A_{r}: C=12, H=1$)

If the molecular formula is $C_{10}H_{22}$, what is the empirical formula?

What is the empirical formula of a compound with $52.2\%$ C, $13.0\%$ H, and $34.8\%$ O? ($A_{r}: C=12, H=1, O=16$)

Which of these molecular formulas matches its empirical formula?

Which of these contains the same empirical formula as $C_{6}H_{12}O_{6}$?

A compound with $M_{r} = 162$ has the empirical formula $C_{5}H_{7}N$. What is its molecular formula? ($A_{r}: C=12, H=1, N=14$)

In the analysis of a salt, $0.1 \text{ mol}$ of the salt was found to contain $4.6 \text{ g}$ of sodium. What is the subscript of sodium in the formula of the salt? ($A_{r}: Na=23$)

A compound contains $40.0\%$ Carbon, $6.7\%$ Hydrogen, and $53.3\%$ Oxygen. $0.050 \text{ moles}$ of the compound has a mass of $9.0 \text{ g}$. What is the molecular formula?

A $10.0 \text{ g}$ sample of a hydrate of $Na_{2}CO_{3}$ was heated until all water was removed. The anhydrous salt remained with a mass of $3.71 \text{ g}$. What is the formula of the hydrate?

What is the empirical formula of a compound containing $21.9\%$ Mg, $27.8\%$ P, and $50.3\%$ O?

What is the volume of $4.8\,g$ of methane gas ($CH_4$) at RTP? ($M_r$ of $CH_4 = 16$, Molar volume = $24.0\,dm^3/mol$)

Calculate the mass of $1.5\,mol$ of carbon atoms, $C$. (Relative atomic mass: $C = 12$)

What is the relative formula mass of potassium chloride, $KCl$? (Relative atomic masses: $K = 39, Cl = 35.5$)

How many moles of water are produced when $2\,mol$ of $H_2$ reacts with excess $O_2$ in the reaction $2H_2 + O_2 \rightarrow 2H_2O$?

A $10.0\,g$ sample of limestone contains $90\%$ calcium carbonate. What volume of carbon dioxide is released when it reacts with excess acid at RTP? ($M_r$ of $CaCO_3 = 100$)

When $0.5\,mol$ of lead(II) nitrate is reacted with $0.5\,mol$ of potassium iodide ($Pb(NO_3)_2 + 2KI \rightarrow PbI_2 + 2KNO_3$), what is the maximum amount of lead(II) iodide that can be formed?

A solution is prepared by dissolving $5.85\,g$ of $NaCl$ ($M_r = 58.5$) in enough water to make $500\,cm^3$ of solution. What is the concentration in $g/dm^3$?

A $5.0\,g$ sample of a mixture of $NaCl$ and $Na_2SO_4$ contains 1.61 g of sodium. What is the mass of $NaCl$ in the mixture? ($A_r: Na=23, Cl=35.5, S=32, O=16$)

How many moles of ions are present in $250\,cm^3$ of $0.40\,mol/dm^3$ $Al_2(SO_4)_3$?

A $2.0\,dm^3$ flask contains $3.2\,g$ of a gas at RTP. What is the $M_r$ of the gas?