Quantitative Chemistry

If you have 100g of a compound and 20g is element A, what is the percentage composition of A?

What is the $M_r$ of carbon monoxide, $CO$? (Atomic masses: $C=12$, $O=16$)

What is the $M_r$ of sulfur trioxide, $SO_3$? (Atomic masses: $S=32$, $O=16$)

Calculate the $M_r$ of nitric acid, $HNO_3$. (Atomic masses: $H=1$, $N=14$, $O=16$)

What is the relative formula mass of butane, $C_4H_{10}$? (Given $A_r$: $C = 12, H = 1$)

Calculate the percentage of copper in copper(II) oxide, $CuO$. (Given $A_r$: $Cu = 63.5, O = 16$)

Which of the following has an $M_r$ of 56? (Given $A_r$: $Fe = 56, Ca = 40, O = 16, C = 12, H = 1, N = 14$)

Calculate the mass of phosphorus in 200 g of calcium phosphate, $Ca_3(PO_4)_2$. (Relative atomic masses: $Ca=40, P=31, O=16$)

A substance contains 24.3% magnesium, 12.1% carbon, and 63.6% oxygen. What is its empirical formula?

Which of the following compounds has the highest percentage of carbon by mass?

Which quantity is represented by the symbol $N_A$?

What is the molar mass of Magnesium Oxide ($MgO$)? (Given $A_r$: $Mg=24$, $O=16$)

How many molecules are in $0.25$ moles of any molecular substance?

If the molar mass of $X$ is $40$ g/mol, how many moles are in $10$ g of $X$?

How many moles of nitrogen gas ($N_2$) contain $1.204 \times 10^{24}$ nitrogen atoms?

Calculate the number of moles of carbon in $0.5$ moles of $C_6H_{12}O_6$.

What is the molar mass of octane, $C_8H_{18}$? ($C=12, H=1$)

If the yield of a reaction is $60\%$, what mass of $CaO$ is actually produced from the decomposition of $20$ g of $CaCO_3$? ($CaCO_3 \rightarrow CaO + CO_2$; $M_{CaCO_3}=100, M_{CaO}=56$)

A sample of gas occupies $2.00 \text{ dm}^3$ at STP. How many molecules are in the sample? (Molar volume $= 22.7 \text{ dm}^3 \text{mol}^{-1}$)

What is the mass percentage of nitrogen in urea, $CO(NH_2)_2$? ($C=12, O=16, N=14, H=1$)

In the reaction $C + O_2 \rightarrow CO_2$, if you have 1 mole of $C$ and 5 moles of $O_2$, which is in excess?

If a reaction produces a gas in an open flask, the recorded mass will:

What is the $M_r$ of $NaOH$? ($Na=23, O=16, H=1$)

How many atoms of Oxygen are in one molecule of $CO_2$?

How many moles of oxygen atoms are in $1$ mole of $Al_2(SO_4)_3$?

A reaction has a percentage yield of $60$. If the theoretical yield was $20$ g, what was the actual yield?

What is the first step in calculating reacting masses?

A reaction between $A$ and $B$ follows the stoichiometry $A + 2B \rightarrow C$. If $0.5\text{ mol}$ of $A$ and $0.8\text{ mol}$ of $B$ are reacted, what is the limiting reactant and how many moles of $C$ are formed?

In the reaction $Cu + 2AgNO_3 \rightarrow Cu(NO_3)_2 + 2Ag$, if $6.35\text{ g}$ of $Cu$ is reacted with $17.0\text{ g}$ of $AgNO_3$, what mass of $Ag$ is produced?

If $5.0\text{ g}$ of $Mg$ is reacted with $5.0\text{ g}$ of $O_2$, what is the mass of $MgO$ produced?

What does the symbol '$L$' or '$N_A$' represent in stoichiometry?

If the molar mass of a substance is 100 $g \cdot mol^{-1}$, what is the mass of 0.25 moles?

How many moles of Chlorine atoms are in 1 mole of Calcium Chloride ($CaCl_2$)?

What is the theoretical yield of a reaction?

What is the total number of atoms in $1$ molecule of glucose, $C_6H_{12}O_6$?

Which volume of $2.0$ $mol \, dm^{-3}$ $HCl$ contains $0.1$ moles of the acid?

When $5.0$ g of sulfur is burned in excess oxygen, what is the theoretical mass of $SO_2$ produced? ($A_r$: $S=32, O=16$)

A $0.20$ mole sample of $P_4$ reacts with $1.0$ mole of $Cl_2$ to form $PCl_3$. How many moles of the excess reactant remain?

If $50.0$ $cm^3$ of $0.100$ mol/$dm^3$ $AgNO_3$ is added to $50.0$ $cm^3$ of $0.100$ mol/$dm^3$ $HCl$, what is the concentration of $H^+$ ions in the final solution (assuming no volume change)?

A compound of nitrogen and oxygen has a molar mass of $92.0$ g/mol and contains $30.4\%$ nitrogen by mass. What is its molecular formula?