If someone can help with either one of these please

Anyone who's in connections academy chemistry b have the factors that affect the rate of a reaction portfolio already done?

How can the number of core electrons be determined from the periodic table

Reacting masses1 calcium carbonate breaks down on heating to produce calcium oxide and carbondioxide gas.caco3 + cao + co2a student heats 15 g of calcium carbonate strongly in a crucible.relative atomic masses (a): ca = 40, c = 12, o = 16.calculate the mass of calcium oxide produced by this reaction.(5 marks)