A student takes out a vol. flask containing 100ml of CuCl2 solution. She pipettes 25.00ml of the solution into a new flask and adds enough water to make 250.00ml of a solution that is 0.01846 M in Cl- ion. How many grams of Cu2+ ion were dissolved in the original 100ml solution?
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Chemistry Problem?
2018-03-20 11:58 am
回答 (1)
2018-03-20 2:33 pm
No. of moles of 250.00 ml of 0.01846 M Cl⁻ ion = (0.01846 mol/L) × (250.00/1000 L) = 0.004615 mol
No. of moles of Cl⁻ ion in 25.00 ml of the original solution = 0.004615 mol
No. of moles of Cl⁻ ion in the original 100 ml solution = (0.004615 mol) × (100/25) = 0.1846 mol
According to the formula CuCl₂, mole ratio Cu²⁺ : Cl⁻ = 1 : 2
No. of moles of Cu²⁺ ion in the original 100 ml solution = (0.01846 mol) × (1/2) = 0.00923 mol
Molar mass of Cu²⁺ ion = 63.55 g/mol
Mass of Cu²⁺ ion in the original 100 ml solution = (0.00923 mol) × (63.55 g/mol) = 0.587 g
No. of moles of Cl⁻ ion in 25.00 ml of the original solution = 0.004615 mol
No. of moles of Cl⁻ ion in the original 100 ml solution = (0.004615 mol) × (100/25) = 0.1846 mol
According to the formula CuCl₂, mole ratio Cu²⁺ : Cl⁻ = 1 : 2
No. of moles of Cu²⁺ ion in the original 100 ml solution = (0.01846 mol) × (1/2) = 0.00923 mol
Molar mass of Cu²⁺ ion = 63.55 g/mol
Mass of Cu²⁺ ion in the original 100 ml solution = (0.00923 mol) × (63.55 g/mol) = 0.587 g
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