Allow the mixture to stand for as long as possible before filtering. 8. Weigh a clean and dry suction funnel, together with a piece of filter paper. 9. Carefully filter the supernatant liquid and then the precipitate. Scrape difficult-to-remove traces of precipitate into the funnel. Rinse the beaker a few times with water and add these washings to the filter paper. 10. Wash the precipitate with several portions of warm water followed by methylated spirits. 11. Dry the crucible and contents in an oven at 110C overnight. 12. Weigh when dry and calculate the mass of barium sulfate produced. 13. Use your results to calculate the percentage of sulfur in the lawn food tested. Mass of Barium sulfate produced: 0.827g Do i need to write an equation between the hydrochloric acid and the SO4 at the start? Ah.. just need some guidance on what to do, cause the whole prac is confusing me.. Should get around 18.60% but there were alot of errors with the buchner funnels and filter paper Best Answer - Chosen by Voters Do i need to write an equation between the hydrochloric acid and the SO4 at the start? Not .. the sulphate ion doesn't react with HCl .. that's just to dissolve everything. I can see your mass of BaSO4 but I can't see the accurate result for 1.Grind up some lawn food in a mortar and pestle, then accurately weigh out about 1.00 g. About 1.00g is not 1.00g .. presumably you had something