You weigh out 1.60 g of sodium carbonate monohydrate, dissolve it in water and react it with 15.00 mL of 2.00 M HCl. Write an equation for the reaction and calculate the expected mass or carbon dioxide that will be produced. Your answer should be a decimal number to 3 decimal places.
Na2CO3 + 2HCl ==> 2NaCl + CO2 + H2O
mols Na2CO3 = grams/molar mass Na2CO3.
Convert to mols CO2 using the coefficients in the balanced equation.
Convert mols CO2 to grams CO2. g CO2 = mols CO2 x molar mass CO2.
I'm a little confused with the instructions. Three decimal places to me means three places AFTER the decimal or 1.xxx which is to four significant figures but you have only three s.f. in 1.60. Using four s.f. in the answer is not allowed.