Stoichiometry Vocabulary Review Worksheet

Press Print worksheet to match twelve stoichiometry terms, from mole and molar mass to percent yield, to their meanings.

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All 36 terms

Moles and ratios 12

balanced equation An equation in which no atom is gained or lost. CH4 + 2O2 → CO2 + 2H2O is balanced: one carbon, four hydrogens and four oxygens on each side.
coefficient The multiplier written before H2O in 2H2O. It applies to the whole formula: two molecules of water, or two moles of it.
excess reactant An ingredient still on hand after the reaction ends. With 3 moles of hydrogen and 1 of oxygen making water, 1 mole of hydrogen is left over.
limiting reactant The ingredient that is used up before the others. It decides how much product can form. Limiting reagent is another name for it.
molar mass The grams of mass in each mole of a material. Its unit is grams per mole. The number is nearly the same as the atomic or formula mass in daltons.
mole A chemist's dozen: the unit that counts particles. One mole is exactly 6.02214076 × 10^23 particles. The symbol is mol.
mole ratio How many moles of one substance go with another. It is read from the coefficients, and is also called the molar ratio. In 2H2 + O2 → 2H2O, hydrogen to oxygen is 2 to 1.

Show all 36 terms (29 more)

Moles and ratios, continued

percent yield Actual yield as a percentage of theoretical yield. A yield close to 100 percent is called quantitative.
product One of the materials a reaction ends with. Products stand to the right of the arrow.
reactant One of the materials a reaction begins with. Reactants stand to the left of the arrow.
stoichiometry The arithmetic of amounts in a chemical reaction. The word was first used in 1792. It joins the Greek words for element and measure.
theoretical yield The most product a reaction could make, by the math. It is worked out from the limiting reactant and the balanced equation.

Mass and formulas 12

atomic mass How heavy one atom is, measured in daltons. The periodic table lists an average for each element.
atomic mass unit The tiny unit used for the masses of atoms. Twelve of them equal the mass of one carbon-12 atom. Its newer name is the dalton.
Avogadro's number How many particles a mole holds: about 6.022 x 10^23. It is named for the Italian scientist Amedeo Avogadro. Written out, it is about 602 sextillion.
chemical formula A compound's makeup written in element symbols. CO2 says one carbon atom and two oxygen atoms.
conversion factor A fraction that changes one unit into another. It always equals one: 2.54 centimeters over 1 inch is the same length on top and bottom.
dimensional analysis Keeping track of units through a calculation. Units cancel the way numbers do: grams times moles per gram leaves moles.
empirical formula A formula showing the simplest ratio of atoms. Glucose is C6H12O6 and its empirical formula is CH2O.
formula mass The sum of the atomic masses in a formula. For table salt, NaCl, it is about 58.44: 22.99 for sodium and 35.45 for chlorine.
formula unit The set of ions that an ionic formula stands for. Table salt has no separate molecules, so chemists count formula units of NaCl.
molecular formula A formula with the true number of atoms per molecule. Formaldehyde, acetic acid and glucose share the simplest ratio CH2O and differ in their molecular formulas.
percent composition Each element's percent share of a compound's mass. Water is about 11 percent hydrogen and 89 percent oxygen by mass.
subscript The small low number after a symbol in a formula. The 2 in H2O says two hydrogen atoms. Balancing an equation never changes a subscript.

Yield, solutions and gases 12

actual yield The product actually collected, weighed in the lab. It is usually less than the math predicts: a reaction may not finish, and some product is lost in filtering.
amount of substance The quantity that is measured in moles. The SI has seven base quantities, and this is one. Its symbol is n.
anhydrous Containing no water. Anhydrous compounds slowly take water from the air, so they are stored with care.
chemical equation A reaction set down in the shorthand of chemistry. The arrow points from the starting materials to the ones formed, with plus signs between the substances.
conservation of mass The law that reactions never make or destroy matter. The products weigh the same as the reactants, which is why an equation has to balance.
hydrate A compound with water held in its crystals. Copper sulfate pentahydrate is CuSO4·5H2O: five waters for each formula unit.
molar volume How much room a mole of gas or liquid fills. At room temperature and normal pressure a mole of any gas fills about 24 liters.
molarity How many moles are dissolved in each liter. One mole of salt in a liter of solution is 1 mole per liter.
significant figures The digits in a measured number that can be trusted. After multiplying or dividing, an answer keeps as many as the measurement with the fewest.
solute The dissolved ingredient of a mixture. In salt water the salt is the solute and the water is the solvent.
standard temperature and pressure Agreed conditions for comparing measurements. STP for short. Until 1982 it meant 0 degrees Celsius and 1 atmosphere; the newer standard pressure is 100 kilopascals.
titration Testing a solution's strength with a known solution. The known solution is added a little at a time until the reaction is just complete.

How this list was compiled: Term list chosen for this site on 2026-10-12. Each meaning is written in our own words and was checked that day against the article on the term in the English Wikipedia (https://en.wikipedia.org/), whose text is under the Creative Commons Attribution-ShareAlike license: Stoichiometry, Mole (unit), Molar mass, Limiting reagent, Yield (chemistry), Chemical equation, Reagent, Product (chemistry), Avogadro constant, Atomic mass, Dalton (unit), Molecular mass, Chemical formula, Empirical formula, Mass fraction (chemistry), Formula unit, Conversion of units, Dimensional analysis, Conservation of mass, Molar concentration, Solution (chemistry), Titration, Molar volume, Standard temperature and pressure, Amount of substance, Hydrate, Water of crystallization, Anhydrous and Significant figures. Empirical formula, molecular formula and formula unit were also read in Wiktionary, the free dictionary (https://en.wiktionary.org/). Mole ratio is the school name for what the article Stoichiometry calls the molar ratio. The mole, moles and masses, limiting and excess reactants and concentration were checked a second time against the BBC Bitesize guide Calculations in chemistry (Higher) (https://www.bbc.co.uk/bitesize/guides/z3kg2nb/revision/1 and the five pages after it); formula mass and the conservation of mass against the guide Calculations in chemistry (https://www.bbc.co.uk/bitesize/guides/zgcyw6f/revision/1 and /2); theoretical yield, percent yield, the reasons a yield falls short and the volume of a mole of gas at room temperature against the guide Atom economy, percentage yield and gas calculations (https://www.bbc.co.uk/bitesize/guides/z8wkh39/revision/2 and /5). The mole and the Avogadro constant were also read in SI Redefinition: Mole of the National Institute of Standards and Technology (https://www.nist.gov/si-redefinition/mole). Every figure in an example is our own working. The fact after each meaning is from the same pages. Licence: own work

How it works

This stoichiometry vocabulary review worksheet lists mole, molar mass, mole ratio, coefficient, limiting reactant, theoretical yield and six more terms down the left, with their meanings mixed up down the right.

Read the full guide

Mass and formulas

Set opens on Moles and ratios. The second set has Avogadro's number, atomic mass, atomic mass unit, formula mass, subscript, chemical formula, empirical formula, molecular formula, percent composition, formula unit, conversion factor and dimensional analysis.

Yield, solutions and gases

The third set has actual yield, conservation of mass, chemical equation, molarity, solute, titration, molar volume, standard temperature and pressure, amount of substance, hydrate, anhydrous and significant figures.

Meanings on the sheet use plain keyboard signs, so Avogadro's number prints as 6.022 x 10^23.

Questions and answers

How do you find the limiting reactant?

Change the amount of each reactant to moles, then divide by its coefficient in the balanced equation. The reactant with the smallest result is used up first, and it sets how much product can form.

What is the formula for percent yield?

Percent yield is the actual yield divided by the theoretical yield, times 100. A reaction that could make 20 grams of product and gives 15 has a percent yield of 75.

How many grams are in a mole?

It depends on the substance: a mole has a mass in grams equal to the molar mass. A mole of carbon is about 12 grams, a mole of water about 18 and a mole of table salt about 58.4.

Does the stoichiometry vocabulary review worksheet have an answer key?

Yes. The key prints as the last page: the same sheet with a line drawn from each term to its meaning, the meanings still in their mixed order.

All 36 terms

Moles and ratios 12

Moles and ratios, continued

Mass and formulas 12

Yield, solutions and gases 12

How it works

Mass and formulas

Yield, solutions and gases

Questions and answers

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