Answer:
8.1g
0.1g
Explanation:
The reaction expression is given as:
Fe + 2HBr → FeBr₂ + H₂
Mass of pure iron given = 2.8g
A. Mass of HBr needed to dissolve a padlock of the mass;
To solve this problem, we need to use the mole concept.
Convert mass of the known iron to the number of moles.
Number of moles =
Molar mass = 56g/mol
Number of moles of iron = = 0.05mole
1 mole of Fe will react with 2 mole of HBr
0.05mole of Fe will react with 0.05 x 2 = 0.1mole of HBr
Mass of HBr = number of moles x molar mass
Molar mass of HBr = 1 + 80 = 81g/mol
Mass of HBr = 0.1 x 81 = 8.1g
B. What mass of H2 would be produced by the complete reaction of the iron bar
Since:
1 mole of Fe will produce 2 mole of hydrogen gas
0.05mole of Fe will produce 2 x 0.05mole = 0.1mole of hydrogen gas
Mass of hydrogen gas = number of moles x molar mass
= 0.1 x 1
= 0.1g