Chemistry calculations explained and worked through. The unit cancellation is shown on every line, since that is the part that decides whether an answer is right and the part textbooks skip.
Formulas in this section
- Moles, mass and molar massn = m ⁄ MConvert between the mass you can weigh and the number of particles you actually need.Grades 9–10
- The dilution formulaC₁V₁ = C₂V₂Work out what to mix when you make a weaker solution from a stronger one.Grades 9–12
- The ideal gas lawPV = nRTTies pressure, volume, amount and temperature of a gas into one equation.Grades 11–12
Everything here comes back to the mole
Nearly every chemistry calculation at this level is a mole calculation wearing a different hat. Get comfortable converting between mass, moles and molar mass and the rest — concentrations, gas volumes, titrations — stops being a set of separate formulas to memorise.
Each page here shows the units cancelling as the numbers go in. If your units do not cancel to the unit you expect, the calculation is wrong no matter how tidy the arithmetic was.