Mg +2HCL = MgCl2 +H2 what mass of hydrogen is obtained by adding excess hydrochloric acid to 6g of magnesium
mols Mg = grams/molar mass
convert mols Mg to mols H2 using the coefficients in the balanced equation.
Finally, grams H2 = mols H2 x molar mass H2.
To determine the mass of hydrogen produced when excess hydrochloric acid reacts with 6g of magnesium, we need to use stoichiometry, which involves the balanced equation for the reaction.
The balanced equation for the reaction is:
Mg + 2HCl → MgCl2 + H2
From the equation, we can see that 1 mole of magnesium (Mg) reacts with 2 moles of hydrochloric acid (HCl) to produce 1 mole of hydrogen gas (H2).
The first step is to calculate the number of moles of magnesium present. To do this, we divide the given mass of magnesium by its molar mass.
The molar mass of magnesium (Mg) is approximately 24.3 g/mol.
Number of moles of magnesium = mass of magnesium / molar mass of magnesium
= 6g / 24.3 g/mol
= 0.247 moles
Since 1 mole of magnesium reacts to produce 1 mole of hydrogen gas, the number of moles of hydrogen gas produced will be equal to the number of moles of magnesium.
Number of moles of hydrogen gas produced = 0.247 moles
Finally, we need to calculate the mass of hydrogen gas produced using its molar mass.
The molar mass of hydrogen (H2) is approximately 2 g/mol.
Mass of hydrogen gas produced = number of moles of hydrogen gas × molar mass of hydrogen
= 0.247 moles × 2 g/mol
= 0.494 g
Therefore, by adding excess hydrochloric acid to 6g of magnesium, the mass of hydrogen gas produced is approximately 0.494 grams.