ions as one mole of mass of that substance and any other substance. vice versa. The number of atoms, WS 4.1, 4.2, 4.3, 4.5, 4.6 molecules or ions in a MS 1a, 1b, 2a, 3b, 3c mole of a given substance is the Avogadro constant. The value of the Avogadro constant is 6.02 × 1023 per mole. 4.5.2.5 The balancing MS 3c, 3d 2.5 Use the masses of substances Use a strip of Video clip numbers in a symbol present in a reaction to write a magnesium ribbon in (HT Pupils should be able to YouTube: equation can be balanced equation. 20 ml HCl acid. Identify only) balance an equation given calculated from the which reactant is the the masses of reactants and Define the term limiting masses of reactants limiting reactant and products. reactant. and products by state the reason for this WS 4.1 Link the limiting reactant to the converting the masses choice. number of moles. in grams to amounts in Pupils should be able to moles and converting explain the effect of a limiting Link the limiting reactant to the the numbers of moles quantity of a reactant on the masses in to simple whole amount of products it is Balance chemical equations number ratios. possible to obtain in terms of and use these to calculate the amounts in moles or masses In a chemical reaction masses of substances present. in grams. involving two Extended writing: reactants, it is MS 1a, 1c, 3c, 3d common to use an Write instructions to another Pupils should be able to: excess of one of the student how to use balanced
ions as one mole of any other substance. The number of atoms, molecules or ions in a mole of a given substance is the Avogadro constant. The value of the Avogadro constant is 6.02 × 1023 per mole. mass of that substance and vice versa. WS 4.1, 4.2, 4.3, 4.5, 4.6 MS 1a, 1b, 2a, 3b, 3c 4.5.2.5 (HT only) The balancing numbers in a symbol equation can be calculated from the masses of reactants and products by converting the masses in grams to amounts in moles and converting the numbers of moles to simple whole number ratios. In a chemical reaction involving two reactants, it is common to use an excess of one of the MS 3c, 3d Pupils should be able to balance an equation given the masses of reactants and products. WS 4.1 Pupils should be able to explain the effect of a limiting quantity of a reactant on the amount of products it is possible to obtain in terms of amounts in moles or masses in grams. MS 1a, 1c, 3c, 3d Pupils should be able to: 2.5 Use the masses of substances present in a reaction to write a balanced equation. Define the term limiting reactant. Link the limiting reactant to the number of moles. Link the limiting reactant to the masses in Balance chemical equations and use these to calculate the masses of substances present. Extended writing: Write instructions to another student how to use balanced Use a strip of magnesium ribbon in 20 ml HCl acid. Identify which reactant is the limiting reactant and state the reason for this choice. Video clip YouTube: