Chemistry / Unit 3 Chem 0423 short lesson, about 20 seconds
Writing a Chemical Equation
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The idea
A chemical equation places reactant formulas left of an arrow and product formulas to its right, with coefficients showing relative amounts.
In practice
Methane burning in oxygen is written CH4 + 2O2 → CO2 + 2H2O, a 1-to-2-to-1-to-2 ratio of reactants to products.
Where people slip
Treating a coefficient-less formula as zero, or forgetting its implied 1 while tallying atoms, undercounts the atom count.
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