Question

Plz solve Q3 in a sheet of paper with proper steps also can we round off 12.70% to 13% in exam will the ans be same can you check while putting 13% as value as i rounded off to whole number also can we round off the mass number of copper to 64u will the be same yes or no also put this value ​

Answer 1

Answer:

21.325 = 21

Explanation:

Gold sample = 1g

% of copper = 12.70

Therefore , Mass of copper = 0.127 g

Mass of gold = 1 - 0.127 = 0.873 g

No. of atoms in 197g of gold = 1 mole

No. of atoms in 1 g of gold = 1mole/ 197

... 0.873 g of gold = 1mole × 0.873/197

= 171.981 mol

No. of atoms in 63.5 g of Cu = 1mole

...0.127 g if Cu = 1mole × 0.127 × 63.5

= 8.0645 mole

Ratio = 171.98 mol /8.06 mol

= 21. 325

approx 21

P.S = Approximate Answer won't change