Answer:
The sample has 50% tin
Explanation:
<u>Step 1:</u> Determine the (half) reactions
Sn(s) → Sn2+(aq)
NO3-(aq) →NO(g)
<u>Step 2:</u> Balance the Oyxgen atoms by adding H+
4H+ NO3- → NO + 2H2O(l)
4H+(aq) + NO3-(aq) -→ NO(g) + 2H2O(l)
<u>Step 3:</u> Balance the charges by adding electrons
Sn(s) → Sn2+(aq) +2e-
4H+(aq) + NO3-(aq) +3e-→ NO(g) + 2H2O(l)
<u>Step 4:</u> To balance the 2 equations we should multiply the first reaction by 3; and multiply the second reaction by 2
3 Sn(s) → 3 Sn2+(aq) +6e-
8H+(aq) + 2 NO3-(aq) +6e-→ 2 NO(g) + 4H2O(l)
3Sn + 8H+ +2NO3- → 3Sn2+ + 2NO +4H2O
<u>Step 5:</u> Calculate moles of NO3-
Moles of NO3- = 0.0448 M * 0.0339 = 0.00152 moles
<u>Step 6: </u>Calculate moles of Sn
As we can see in the balanced equation, for 2 moles of NO3- Consumed, we need 3 moles of Sn to consume.
This means that for 0.00152 moles of NO3- we need 0.00152 * (3/2) = 0.00228 moles of Sn
<u>Step 7:</u> Calculate mass of Sn
mass of Sn = moles of Sn * Molar mass of Sn
mass of Sn = 0.00228 moles * 118.71g/mole = 0.27 grams
<u>Step 8:</u> Calculate the mass %
(0.27g / 0.54g) * 100 % = 50%
The sample has 50% tin