Question

1. calculate the average atomic mass of hydrogen with the following isotopes: h - 1 = 99%, h - 2 = 0.8%, h - 3 = 0.2%.

Explanation:

Step1: Recall average - atomic - mass formula

The formula for average atomic mass is $\sum_{i}(m_i\times p_i)$, where $m_i$ is the mass of the isotope and $p_i$ is its percent - abundance in decimal form.

Step2: Convert percent - abundances to decimals

$H - 1$: $p_1=0.99$, $H - 2$: $p_2 = 0.008$, $H - 3$: $p_3=0.002$. Assume the mass of $H - 1$ is $1\ amu$, the mass of $H - 2$ is $2\ amu$, and the mass of $H - 3$ is $3\ amu$.

Step3: Calculate the average atomic mass

\[

$$\begin{align*} \text{Average atomic mass}&=(1\times0.99)+(2\times0.008)+(3\times0.002)\\ &=0.99 + 0.016+0.006\\ &=1.012\ amu \end{align*}$$

\]

Answer:

1.012 amu