Question

question 10 1 pts how many hydrogen atoms are in 0.62 g of propane, c₃h₈? report your answer in proper scientific notation to the correct number of sig figs by filling in the following blanks, but do not include units in your answer. × 10

Explanation:

Step1: Calculate molar mass of propane

The molar mass of $C_3H_8$: $M=(3\times12.01 + 8\times1.01)\text{ g/mol}=44.11\text{ g/mol}$

Step2: Calculate moles of propane

$n=\frac{m}{M}=\frac{0.62\text{ g}}{44.11\text{ g/mol}}\approx0.01406\text{ mol}$

Step3: Calculate moles of hydrogen atoms

In 1 mole of $C_3H_8$, there are 8 moles of H - atoms. So moles of H - atoms in 0.01406 mol of $C_3H_8$ is $n_H = 0.01406\text{ mol}\times8 = 0.11248\text{ mol}$

Step4: Calculate number of hydrogen atoms

Using Avogadro's number $N_A = 6.022\times10^{23}\text{ atoms/mol}$, the number of H - atoms $N=n_H\times N_A=0.11248\text{ mol}\times6.022\times10^{23}\text{ atoms/mol}=6.7735456\times10^{22}$ atoms. In scientific notation to 2 sig - figs, it is $6.8\times 10^{22}$

Answer:

$6.8$
$22$