You are going to be provided with 1 0.50 g sample of magnesium oxide. Treatment of this sample with hydrochloric acid (HCl) will take all of the MAGNESIUM in the oxide and change it into magnesium chloride, MgCl2
You will add 100 ml of 1.0 M HCl to the 0.50 g of magnesium oxide in a 250 ml beaker. After the bubbling goes away, you will need to boil off the water until the MgCl2 product in the beaker has come to constant mass.
A. What data will you need to determine the mass of MgCl2 you recover?
B. How will you determine the amount of Mg present in your product?
C. How will you use your knowledge of the amount of Mg to determine the empirical formula of magnesium oxide?
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A. To determine the mass of MgCl2 you recover, you will need the mass of the empty beaker before adding the magnesium oxide, the mass of the beaker with the magnesium oxide, and the mass of the beaker with the final product (MgCl2).
B. To determine the amount of Mg present in your product, you need to use stoichiometry. First, calculate the number of moles of MgO (magnesium oxide) by dividing the mass of MgO by its molar mass. The molar mass of MgO is found by adding the atomic masses of magnesium (24.31 g/mol) and oxygen (16.00 g/mol), which makes it 40.31 g/mol.
Next, using the balanced chemical equation:
MgO + 2HCl -> MgCl2 + H2O
we can see that for every 1 mole of MgO reacted, we get 1 mole of MgCl2. Therefore, the number of moles of MgCl2 is equal to the number of moles of MgO.
Finally, to calculate the mass of Mg present in the product, multiply the number of moles of MgCl2 by the molar mass of MgCl2 (magnesium chloride). The molar mass of MgCl2 is found by adding the atomic mass of magnesium (24.31 g/mol) and two times the atomic mass of chlorine (2 * 35.45 g/mol), which gives a molar mass of 95.21 g/mol.
C. To determine the empirical formula of magnesium oxide, you will use the Law of Definite Proportions. The empirical formula represents the simplest whole-number ratio of the elements in a compound.
First, calculate the moles of Mg and moles of O in the MgO product. The moles of Mg can be calculated by dividing the mass of Mg by its molar mass, while the moles of O can be calculated by dividing the mass of O (found by subtracting the mass of Mg from the mass of MgO) by its molar mass.
Next, divide the moles of Mg and moles of O by the smallest value among them. This will give you the empirical formula of magnesium oxide. For example, if we find that there are 0.01 moles of Mg and 0.01 moles of O, we would divide both by 0.01 to get a 1:1 ratio, which gives us the empirical formula of MgO.