Reacting Masses Calculator
⚗ Moles & Stoichiometry. Use the Reacting masses formula to find mass of product, mass of reactant, mr of reactant, mr of product, ratio: reactant (a), ratio: product (b): pick the value you want, type the others, and the answer updates as you go.
From a mass of one chemical to the mass of another, using the ratio a : b from the balanced equation.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Mass of product | g |
| Mass of reactant | g |
| Mr of reactant | g/mol |
| Mr of product | g/mol |
| Ratio: reactant (a) | no unit |
| Ratio: product (b) | no unit |
Worked example
Find the mass of product when Mass of reactant = 10 g, Mr of reactant = 100 g/mol, Mr of product = 44 g/mol, Ratio: reactant (a) = 1, Ratio: product (b) = 1.
Using m2 = m1/M1 × b/a × M2: Mass of product = 4.4 g.
Frequently asked questions
What is the formula for Reacting masses?
m2 = m1/M1 × b/a × M2. From a mass of one chemical to the mass of another, using the ratio a : b from the balanced equation.
What do the letters stand for, and what units are used?
Mass of product in g, Mass of reactant in g, Mr of reactant in g/mol, Mr of product in g/mol, Ratio: reactant (a), Ratio: product (b).
How do you calculate mass of product?
Put the values into m2 = m1/M1 × b/a × M2. For example, with Mass of reactant = 10 g, Mr of reactant = 100 g/mol, Mr of product = 44 g/mol, Ratio: reactant (a) = 1, Ratio: product (b) = 1, mass of product = 4.4 g.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (mass of product, mass of reactant, mr of reactant, mr of product, ratio: reactant (a), ratio: product (b)) and fill in the others: it rearranges the formula for you.
