A chemistry student prepares lead(II) iodide from 1.35 g of lead (II) nitrate and excess aqueous potassium iodide. If the student collected 1.72 g of PbI2 and the theoretical yield is 1.88 g, what is the percent yield? A 1.95 g sample of potassium bicarbonate is decomposed by heating. If the resulting potassium carbonate weighs 1.54 g and the calculated yield is 1.35 g, what is the percent yield? can anyone help me with either of these I'm very lost D: