To calculate the expected volume of carbon dioxide (CO2) in this experiment, you need to start by finding the number of moles of MgCO3 used. You already have the moles of H2SO4 (sulfuric acid) as 0.005 mol.
First, calculate the moles of MgCO3 using its molar mass:
Molar mass of MgCO3 = (Molar mass of Mg) + (Molar mass of C) + 3*(Molar mass of O)
= 24.31 + 12.01 + 3*(16.00)
= 84.31 g/mol
Given that 0.30 g of MgCO3 was used, you can calculate the moles using the formula:
moles = mass (in grams) / molar mass
moles MgCO3 = 0.30 g / 84.31 g/mol
= 0.00356 mol (rounded to five decimal places)
Now, you can calculate the expected volume of CO2. One mole of any gas occupies 24.0 dm3 at standard temperature and pressure (STP). Therefore, the expected volume can be calculated by multiplying the moles of CO2 by 24.0:
Expected volume of CO2 = moles of CO2 * 24.0 dm3
Expected volume of CO2 = 0.00356 mol * 24.0 dm3/mol
= 0.0854 dm3
= 85.4 cm3 (rounded to three significant figures)
So, the expected volume of carbon dioxide is 85.4 cm3, which is greater than the 64 cm3 obtained in the experiment.
Now, let's move on to the mark scheme for the last questions:
d) To carry out the experiment more accurately, the procedure and measuring apparatus could be modified. Unfortunately, without access to the mark scheme for the question, I cannot provide a detailed explanation of the modifications required. However, the mark scheme should provide a diagram and descriptions of the modifications needed. You can refer to it for a better understanding.
e) If the sulfuric acid used in the procedure is replaced with the same concentration and volume of hydrochloric acid (HCl), some modifications are needed. Hydrochloric acid is a strong acid, and it may react more rapidly and forcefully with the magnesium carbonate. Therefore, you may need to use a different setup or apparatus to control the reaction rate and avoid excessive gas release. Additionally, you may need to consider the stoichiometry and reactivity of HCl compared to H2SO4 and adjust the quantities or concentrations of reagents accordingly. The mark scheme should provide specific suggestions and reasoning for these modifications.