Question

Platinum has a molar mass of 195 g/mol. If you have a ring that contains 2.3 g of platinum, how many moles does it contain? (A)0.012 mol (B) 85 mol (C)450 mol (D) 7.2 x 10^21 mol

Answer 1

Answer:

correct answer is option (A) 0.012 mol

Explanation:

Given:

Molar mass of the platinum, M = 195 g/mol

Mass of the platinum in the ring, m = 2.3 g

Now,

the number of moles (n) is calculated as :

$\textup{n}=\frac{\textup{Given mass}}{\textup{Molar mass}}$

thus,

on substituting the respective values in the formula, we get

$\textup{n}=\frac{2.3\ g}{195\ g\mol}$

or

n = 0.01179 mol ≈ 0.012 mol

Hence, the correct answer is option (A) 0.012 mol