Hydrogen gas can be produced in the lab by the reaction of magnesium metal and hydrochloric acid. Mg + 2 HC -> MgCl2 + H2 How many grams of hydrogen gas will be produce if 5.00 g of magnesium metal is dissolved in excess acid.
To calculate the grams of hydrogen gas produced, we need to use stoichiometry. Stoichiometry allows us to relate the number of moles of reactants and products in a chemical reaction.
First, we need to find the number of moles of magnesium (Mg) using its molar mass. The molar mass of magnesium is 24.31 g/mol.
Number of moles of Mg = mass of Mg / molar mass of Mg
= 5.00 g / 24.31 g/mol
Next, we need to use the stoichiometry of the reaction to determine the ratio of moles of magnesium to moles of hydrogen gas produced. From the balanced equation:
1 mole of Mg reacts to produce 1 mole of H2
Finally, we can convert the moles of hydrogen gas to grams using the molar mass of hydrogen, which is 2.02 g/mol:
Mass of H2 = moles of H2 × molar mass of H2
Now we can solve the problem:
1. Calculate the moles of Mg:
Moles of Mg = 5.00 g / 24.31 g/mol
2. Using stoichiometry, we know that:
Moles of H2 = Moles of Mg
3. Calculate the mass of H2:
Mass of H2 = Moles of H2 × molar mass of H2
Substituting the values, we can solve for the mass of H2 produced.