A 4.00g piece of magnesium is added to 200mL of 1.40 mol/l HC.
Identify the limiting reactant, and calculate the mass of hydrogen gas that should be produced
This is a limiting reagent (LR) problem. You know that because amounts are given for BOTH reagents. I suppose you means HCl for HC.
1. Write and balance the equation.
2. Convert grams Mg to mols. mols = grams/atomic mass = ?
3. Convert HCl to mols. mols HCl = M x L = ?
4. Using the coefficients in the balanced equation, convert mols Mg to mols H2.
5. Do the same and convert mols HCL to mols H2.
6. It is likely that the values for mols H2 produced in the above steps will not be the same which means one of them is not right. The correct value in LR problems is ALWAYS the smaller value and the reagent responsible for that value is the LR.
7. Using the smaller value, convert mols H2 to grams H2. g = mols x molar mass = ? This is the theoretical yield.
To determine the limiting reactant, we need to compare the number of moles of magnesium and hydrochloric acid to see which one will run out first.
First, let's find the number of moles of magnesium using its molar mass:
Mass of magnesium = 4.00 g
Molar mass of magnesium (Mg) = 24.31 g/mol
Number of moles of magnesium = Mass / Molar mass
Number of moles of magnesium = 4.00 g / 24.31 g/mol
Now, let's find the number of moles of hydrochloric acid using its molarity and volume:
Molarity of hydrochloric acid (HC) = 1.40 mol/L
Volume of hydrochloric acid (HC) = 200 mL = 0.200 L
Number of moles of hydrochloric acid = Molarity x Volume
Number of moles of hydrochloric acid = 1.40 mol/L x 0.200 L
Now, compare the number of moles of magnesium and hydrochloric acid. The reactant with the smaller number of moles is the limiting reactant.
If the number of moles of magnesium is smaller, it will be the limiting reactant. Otherwise, if the number of moles of hydrochloric acid is smaller, it will be the limiting reactant.
Once we determine the limiting reactant, we can calculate the mass of hydrogen gas produced using the balanced chemical equation and stoichiometry.
Please provide the balanced chemical equation for the reaction between magnesium and hydrochloric acid.