If 6.5g of zinc react with 5g of Hcl
Zn+2Hcl=zncl2+H2
How many grams of the reactant remain unreacted?
To determine the grams of the reactant that remain unreacted, we first need to calculate the limiting reactant, which is the reactant that limits the amount of product formed.
1. Calculate the number of moles of zinc:
Molar mass of zinc = 65.38 g/mol
Number of moles of zinc = mass of zinc / molar mass of zinc
= 6.5 g / 65.38 g/mol
= 0.0994 mol
2. Calculate the number of moles of hydrochloric acid (HCl):
Molar mass of HCl = 36.46 g/mol
Number of moles of HCl = mass of HCl / molar mass of HCl
= 5 g / 36.46 g/mol
= 0.137 mol
3. Determine the limiting reactant:
From the balanced chemical equation, the stoichiometric ratio between zinc and hydrochloric acid is 1:2. This means that 1 mol of zinc reacts with 2 mol of hydrochloric acid.
The number of moles of hydrochloric acid is larger than the number of moles of zinc, meaning that zinc is the limiting reactant.
4. Calculate the amount of product formed:
Since zinc is the limiting reactant, the number of moles of zinc chloride formed will be equal to the number of moles of zinc:
Number of moles of zinc chloride = Number of moles of zinc
= 0.0994 mol
5. Calculate the mass of the unreacted hydrochloric acid:
Mass of unreacted hydrochloric acid = initial mass of hydrochloric acid - moles of hydrochloric acid used * molar mass of hydrochloric acid
= (0.137 mol - 0.0994 mol) * 36.46 g/mol
= 1.37 g
Therefore, 1.37 grams of hydrochloric acid remain unreacted.