PLEASE HELP ASAP I NEED TO HAND IN TOMORROW A chemist prepares an aqueous solution of magnesium chloride using a redox reaction between magnesium and dilute hydrochloric acid. The equation for the reaction is shown below:
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

The chemist reacts 8.1 x 10+g of magnesium with a solution of 0.500 mol dm-3 hydrochloric acid.

a) Calculate the amount, in moles, of magnesium in 8.1 x 10-'g of pure magnesium. Give your answer to an appropriate number of significant figures. 2 marks

b) Calculate the amount, in moles of hydrochloric acid required to react with 8.1 x 10-'g of magnesium. Give your answer to an appropriate number of significant figures. 1 mark​