Question #b69fa
1 Answer
in order to determine the mass of MgO produced when 50g of Mg react with
Step 1.
Write and balance the equation for the combustion of magnesium.
Step 2.
Convert what you have (50g Mg) to moles.
moles = grams/molar mass. Molar mass is the atomic weight in g/mol.
moles Mg = 50g Mg/ 24g/mol = 2.1 mol Mg
Step 3.
Using the coefficients in the balanced equation, convert moles of what you have (moles Mg) to moles of what you want (moles of MgO).
2.1 mol Mg x (2mol MgO/2 mol Mg) = 2.1 mol MgO
Step 4.
Convert moles from step 3 to grams.
moles x molar mass = grams
2.1 mol MgO x 40g/mol = 84g MgO = 80g MgO due to 50g Mg having only one significant figure.