Q111CP - Chemistry: Molecular Nature Of Matter And Change

Question

The mole is defined in terms of the carbon-12 atom. Use the definition to find (a) the mass in grams equal to 1 atomic mass unit; (b) the ratio of the gram to the atomic mass unit.

Step-by-Step Solution

Answer

(a) The mass in gram that is equal to 1 amu is 1.661 x 10^-24 g ¹²c

(b) The ratio of the gram to amu is 1.661 x 10^-24 g / amu

a. Step 1: Finding the mass in grams equal to 1 atomic mass unit

It is known that:

$\begin{array}{l}m{}^{12}C=12 amu\\ 1 amu=\frac{1}{12}.\left(m{}^{12}C\right)\\ =\frac{1}{12}.\frac{12 g}{{6.022.10}^{23}}\\ =1.661\times {10}^{-24}g.\end{array}$

b. Step 2: Finding the ratio of the gram to the atomic mass unit

The ratio of the gram to atomic mass unit is 1.661 x 10^-24 g/amu