MgCO3+2HCL=MgCL2+H20+CO2
when 75.0cm3 of 0.500 mol dm-3 hydrochloric acid were added to 1.25g of impure MgCO3 some acid was left unreacted this unreacted acid required 21.6cm of a 0.500mol dm-3 solution of sodium hydroxide for complete reaction
calculate the number of moles of hcl in 75.0cm3 of 0.500 mol dm-3 hydrochloric acid
calculate the number of moles of NaOH used to neutralise the unreacted HCL
show that the number of moles of HCL which reacted with the MgCO3 in the sample was 0.0267
calculate the number of moles and the mass of MgC03 in the sample and hence deduce the percentage by mass of MgCO3 in the sample

can you explain step by step how you do each point

a compound contains 36.5% of sodium and 25.5% of sulfur by mass the rest being oxygen
use this information to show that the empirical formula of the compound is Na2SO3
when Na2SO3 is treated with an excess of hydrochloric acid aqueous sodium chloride is formed and sulfur dioxide gas is evolved write a balanced equation to show reaction

What volume of CO2 is produced from the complete combustion of 1 litre of petrol with a density of 917.86g/dm3-assume petrol is C8H18 and it occurs at 25 degrees Celsius and 100kpa

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