Stoichiometry - AP Chemistry
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What is the molar mass of $H_2SO_4$?
What is the molar mass of $H_2SO_4$?
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98.1 g/mol. 2H (2) + S (32) + 4O (64) = 98 g/mol total.
98.1 g/mol. 2H (2) + S (32) + 4O (64) = 98 g/mol total.
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Calculate the percent composition of oxygen in $H_2O$.
Calculate the percent composition of oxygen in $H_2O$.
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88.81%. Oxygen mass ($16$) divided by $H_2O$ mass ($18$) $\times 100%$.
88.81%. Oxygen mass ($16$) divided by $H_2O$ mass ($18$) $\times 100%$.
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What is the concentration of a solution with 5 moles of solute in 2 L of solution?
What is the concentration of a solution with 5 moles of solute in 2 L of solution?
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2.5 M. $\frac{5 \text{ moles}}{2 \text{ L}} = 2.5$ M concentration.
2.5 M. $\frac{5 \text{ moles}}{2 \text{ L}} = 2.5$ M concentration.
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Find the moles of $H_2O$ in 36 grams.
Find the moles of $H_2O$ in 36 grams.
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2 moles. $36 \div 18 = 2$ using $H_2O$ molar mass of 18 g/mol.
2 moles. $36 \div 18 = 2$ using $H_2O$ molar mass of 18 g/mol.
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What is the formula to calculate the number of particles from moles?
What is the formula to calculate the number of particles from moles?
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$\text{particles} = \text{moles} \times 6.022 \times 10^{23}$. Multiplies moles by Avogadro's number for particle count.
$\text{particles} = \text{moles} \times 6.022 \times 10^{23}$. Multiplies moles by Avogadro's number for particle count.
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Determine the empirical formula for a compound with 40% carbon, 6.7% hydrogen, and 53.3% oxygen.
Determine the empirical formula for a compound with 40% carbon, 6.7% hydrogen, and 53.3% oxygen.
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$CH_2O$. Convert percentages to moles, then find simplest ratio.
$CH_2O$. Convert percentages to moles, then find simplest ratio.
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Find the molar mass of $CO_2$.
Find the molar mass of $CO_2$.
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44 g/mol. Carbon (12) + 2 oxygen atoms (16 each) = 44 g/mol.
44 g/mol. Carbon (12) + 2 oxygen atoms (16 each) = 44 g/mol.
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What is the formula for molarity?
What is the formula for molarity?
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$\text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liters of solution}}$. Relates amount of solute to solution volume.
$\text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liters of solution}}$. Relates amount of solute to solution volume.
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How do you calculate mass from moles?
How do you calculate mass from moles?
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$\text{mass (g)} = \text{moles} \times \text{molar mass (g/mol)}$. Multiplies moles by molar mass to get mass in grams.
$\text{mass (g)} = \text{moles} \times \text{molar mass (g/mol)}$. Multiplies moles by molar mass to get mass in grams.
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State Avogadro's number.
State Avogadro's number.
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$6.022 \times 10^{23}$. The number of particles in one mole of any substance.
$6.022 \times 10^{23}$. The number of particles in one mole of any substance.
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What is the first step in a stoichiometry problem?
What is the first step in a stoichiometry problem?
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Write a balanced chemical equation. Ensures atom conservation for stoichiometric calculations.
Write a balanced chemical equation. Ensures atom conservation for stoichiometric calculations.
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How is theoretical yield calculated?
How is theoretical yield calculated?
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Use stoichiometry from the balanced equation. Assumes complete reaction with limiting reactant consumed.
Use stoichiometry from the balanced equation. Assumes complete reaction with limiting reactant consumed.
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What is the purpose of a mole ratio in stoichiometry?
What is the purpose of a mole ratio in stoichiometry?
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To convert between moles of different substances. Uses coefficients from balanced equations for conversions.
To convert between moles of different substances. Uses coefficients from balanced equations for conversions.
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Calculate the number of molecules in 2 moles of $H_2$.
Calculate the number of molecules in 2 moles of $H_2$.
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$1.204 \times 10^{24}$ molecules. $2 \times 6.022 \times 10^{23}$ molecules per mole.
$1.204 \times 10^{24}$ molecules. $2 \times 6.022 \times 10^{23}$ molecules per mole.
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What is the stoichiometric coefficient for $H_2$ in $2H_2 + O_2 \rightarrow 2H_2O$?
What is the stoichiometric coefficient for $H_2$ in $2H_2 + O_2 \rightarrow 2H_2O$?
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- Coefficient shows 2 molecules react in balanced equation.
- Coefficient shows 2 molecules react in balanced equation.
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Which unit is used to express concentration in stoichiometry?
Which unit is used to express concentration in stoichiometry?
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Molarity (M). Standard concentration unit for solution calculations.
Molarity (M). Standard concentration unit for solution calculations.
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How many moles of $H_2$ are needed to produce 2 moles of $NH_3$ in $N_2 + 3H_2 \rightarrow 2NH_3$?
How many moles of $H_2$ are needed to produce 2 moles of $NH_3$ in $N_2 + 3H_2 \rightarrow 2NH_3$?
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3 moles. 3:2 mole ratio from balanced equation coefficients.
3 moles. 3:2 mole ratio from balanced equation coefficients.
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What is the molecular formula for a compound with empirical formula $CH_2O$ and molar mass 180 g/mol?
What is the molecular formula for a compound with empirical formula $CH_2O$ and molar mass 180 g/mol?
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$C_6H_{12}O_6$. $180 \div 30 = 6$, so multiply $CH_2O$ by 6.
$C_6H_{12}O_6$. $180 \div 30 = 6$, so multiply $CH_2O$ by 6.
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What is the formula to calculate the number of moles from mass?
What is the formula to calculate the number of moles from mass?
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$\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}$. Divides mass by molar mass to find amount in moles.
$\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}$. Divides mass by molar mass to find amount in moles.
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Determine the limiting reactant in $2H_2 + O_2 \rightarrow 2H_2O$ given 5 moles $H_2$ and 2 moles $O_2$.
Determine the limiting reactant in $2H_2 + O_2 \rightarrow 2H_2O$ given 5 moles $H_2$ and 2 moles $O_2$.
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$H_2$. Needs 2.5 moles $O_2$, but only 2 available, so $H_2$ limits.
$H_2$. Needs 2.5 moles $O_2$, but only 2 available, so $H_2$ limits.
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What is the molar mass of $H_2SO_4$?
What is the molar mass of $H_2SO_4$?
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98.1 g/mol. 2H (2) + S (32) + 4O (64) = 98 g/mol total.
98.1 g/mol. 2H (2) + S (32) + 4O (64) = 98 g/mol total.
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What is the formula for percent yield?
What is the formula for percent yield?
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$\text{Percent yield} = \frac{\text{actual yield}}{\text{theoretical yield}} \times 100$. Compares actual to theoretical yield as a percentage.
$\text{Percent yield} = \frac{\text{actual yield}}{\text{theoretical yield}} \times 100$. Compares actual to theoretical yield as a percentage.
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Convert 3 moles of $NaCl$ to grams.
Convert 3 moles of $NaCl$ to grams.
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175.5 grams. $3 \times 58.5 = 175.5$ using $NaCl$ molar mass.
175.5 grams. $3 \times 58.5 = 175.5$ using $NaCl$ molar mass.
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Calculate the volume at STP for 0.5 moles of gas.
Calculate the volume at STP for 0.5 moles of gas.
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11.2 L. $0.5 \times 22.4 = 11.2$ liters at STP.
11.2 L. $0.5 \times 22.4 = 11.2$ liters at STP.
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What is empirical formula?
What is empirical formula?
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The simplest whole-number ratio of atoms. Shows simplest ratio without molecular complexity.
The simplest whole-number ratio of atoms. Shows simplest ratio without molecular complexity.
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Identify the limiting reactant in 4 moles $N_2$ and 10 moles $H_2$ for $N_2 + 3H_2 \rightarrow 2NH_3$.
Identify the limiting reactant in 4 moles $N_2$ and 10 moles $H_2$ for $N_2 + 3H_2 \rightarrow 2NH_3$.
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$H_2$. Need 12 moles $H_2$ but only have 10; $H_2$ limits.
$H_2$. Need 12 moles $H_2$ but only have 10; $H_2$ limits.
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Identify the unit for molar mass.
Identify the unit for molar mass.
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grams per mole (g/mol). Standard unit expressing mass per mole of substance.
grams per mole (g/mol). Standard unit expressing mass per mole of substance.
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Find the moles of $H_2O$ in 36 grams.
Find the moles of $H_2O$ in 36 grams.
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2 moles. $36 \div 18 = 2$ using $H_2O$ molar mass of 18 g/mol.
2 moles. $36 \div 18 = 2$ using $H_2O$ molar mass of 18 g/mol.
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What is the formula to calculate the number of particles from moles?
What is the formula to calculate the number of particles from moles?
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$\text{particles} = \text{moles} \times 6.022 \times 10^{23}$. Multiplies moles by Avogadro's number for particle count.
$\text{particles} = \text{moles} \times 6.022 \times 10^{23}$. Multiplies moles by Avogadro's number for particle count.
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Determine the empirical formula for a compound with 40% carbon, 6.7% hydrogen, and 53.3% oxygen.
Determine the empirical formula for a compound with 40% carbon, 6.7% hydrogen, and 53.3% oxygen.
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$CH_2O$. Convert percentages to moles, then find simplest ratio.
$CH_2O$. Convert percentages to moles, then find simplest ratio.
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