Stoichiometry Formulas (AI)

Question 1

What is the formula used to calculate the number of moles of a substance?

Answer 1

Number of moles = Mass (g) / Molar mass (g/mol)

Question 2

True or False: The Law of Conservation of Mass states that mass can be created or destroyed in a chemical reaction.

Answer 2

False

Question 3

Fill in the blank: In a balanced chemical equation, the number of ________ must be the same on both sides.

Answer 3

atoms

Question 4

What is the molar mass of water (H2O)?

Answer 4

18.02 g/mol

Question 5

What is the formula to convert between moles and volume of a gas at standard temperature and pressure (STP)?

Answer 5

Volume (L) = Number of moles × 22.4 L/mol

Question 6

What does the symbol ‘ΔH’ represent in a chemical equation?

Answer 6

Change in enthalpy (heat content)

Question 7

What is the stoichiometric coefficient?

Answer 7

The number in front of a compound in a balanced equation that indicates the ratio of moles.

Question 8

True or False: Stoichiometry allows for the calculation of reactants and products in a chemical reaction.

Answer 8

True

Question 9

What is the ideal gas law formula?

Answer 9

PV = nRT

Question 10

Fill in the blank: The ________ of a reaction is the maximum amount of product that can be formed from given reactants.

Answer 10

theoretical yield

Question 11

What is the formula for calculating percent yield?

Answer 11

Percent yield = (Actual yield / Theoretical yield) × 100%

Question 12

In the reaction 2H2 + O2 -> 2H2O, what is the mole ratio of hydrogen to water?

Answer 12

1:1

Question 13

What does ‘limiting reactant’ mean?

Answer 13

The reactant that is completely consumed first in a reaction, limiting the amount of product formed.

Question 14

What is Avogadro’s number?

Answer 14

6.022 × 10^23 particles/mol

Question 15

What is the formula for calculating the number of molecules from moles?

Answer 15

Number of molecules = Number of moles × Avogadro’s number

Question 16

True or False: A balanced equation ensures the same number of each type of atom on both sides.

Answer 16

True

Question 17

What is the formula for calculating the mass of a substance from moles?

Answer 17

Mass (g) = Number of moles × Molar mass (g/mol)

Question 18

What does the term ‘exothermic reaction’ refer to?

Answer 18

A reaction that releases heat.

Question 19

What is the formula for calculating the molarity of a solution?

Answer 19

Molarity (M) = Moles of solute / Liters of solution

Question 20

Fill in the blank: In a chemical reaction, the ________ is the substance that undergoes change.

Answer 20

reactant

Question 21

What is the general stoichiometric formula for combustion reactions?

Answer 21

Hydrocarbon + O2 -> CO2 + H2O

Question 22

What is the formula for finding the concentration of moles in a solute

Answer 22

Concentration = Moles of solute / Volume of solution (L)

Question 23

True or False: The empirical formula represents the actual number of atoms in a molecule.

Answer 23

False

Question 24

What is the empirical formula for glucose (C6H12O6)?

Answer 24

CH2O

Question 25

What is the formula to calculate the number of grams in a given number of moles?

Answer 25

Mass (g) = Moles × Molar mass (g/mol)

Question 26

In the reaction 4Fe + 3O2 -> 2Fe2O3, what is the mole ratio of iron to oxygen?

Answer 26

4:3

Question 27

What is the formula for calculating the volume of a gas at non-STP conditions?

Answer 27

Use the ideal gas law: PV = nRT

Question 28

Fill in the blank: The ________ of a reaction is the amount of product actually obtained.

Answer 28

actual yield

Question 29

What is the formula to find the number of moles from the mass of a solute?

Answer 29

Number of moles = Mass (g) / Molar mass (g/mol)

Question 30

What is the definition of a balanced chemical equation?

Answer 30

An equation where the number of atoms for each element is the same on both sides.

Question 31

True or False: Stoichiometric calculations can only be performed with solid reactants.

Answer 31

False

Question 32

What does the term 'yield' refer to in stoichiometry?

Answer 32

The amount of product produced in a chemical reaction.

Question 33

What is the purpose of stoichiometry in chemistry?

Answer 33

To relate quantities of reactants and products in a chemical reaction.

Question 34

What is the formula for calculating the mole fraction of a component in a mixture?

Answer 34

Mole fraction = Moles of component / Total moles of all components

Question 35

In stoichiometry, what do you call the reactant that is not completely used up?

Answer 35

Excess reactant

Question 36

What is the definition of a molecular formula?

Answer 36

A formula that shows the actual number of atoms of each element in a molecule.

Question 37

What is the formula for calculating the number of moles from volume and molarity?

Answer 37

Number of moles = Molarity (M) × Volume (L)

Question 38

What is the relationship between stoichiometric coefficients and moles?

Answer 38

Stoichiometric coefficients represent the ratio of moles of reactants and products.

Question 39

True or False: The molar mass of a compound is the sum of the atomic masses of its elements.

Answer 39

True

Question 40

What is the formula for calculating the change in energy during a reaction?

Answer 40

ΔE = E(products) - E(reactants)

Question 41

What is the significance of the coefficients in a balanced equation?

Answer 41

They indicate the relative amounts of reactants and products involved in the reaction.

Question 42

Fill in the blank: The ________ of a reaction is a measure of the efficiency of the reaction.

Answer 42

percent yield

Question 43

What is the formula for calculating the total pressure in a mixture of gases?

Answer 43

Total pressure = P1 + P2 + P3 + ... + Pn (Dalton's Law)

Question 44

What is the purpose of a limiting reactant in a chemical reaction?

Answer 44

To determine the maximum amount of product that can be formed.