 To determine the coefficients in a balanced equation, we often use the method of continuous variations. We start out with solutions that have equal molar concentrations and combine them in different volume ratios. Since the concentrations are the same, the volume ratios are the same as the mole ratios of the reactants. We will carry out a reaction between calcium chloride and sodium oxalate. We have a series of test tubes. In test tube one, we're going to put zero drops of calcium chloride. In test tube two, we're going to place one drop of calcium chloride. In test tube two, we'll place two drops. Test tube three, we'll place three drops. Test tube four, four drops, and so on. We will now add sodium oxalate to each one of the test tubes. We want the total volume of each solution to be also constant. So we'll make sure that the total number of drops in each test tube is ten. We'll place ten drops of sodium oxalate in test tube one. Nine drops in test tube two. Eight in test tube three. Seven in test tube four, and so on. We will thoroughly mix the calcium chloride and sodium oxalate in each tube. We'll then let the tube stand and measure the height of the solid in each of the tubes.