# Question fd627

Jul 30, 2017

$8 \times {10}^{23}$ $\text{protons }$ (one significant figure)

#### Explanation:

We're asked to find the number of nucleic protons in $2$ ${\text{g CH}}_{4}$.

To do this, we can first use the molar mass of methane to convert from grams to moles:

2cancel("g CH"_4)((1color(white)(l)"mol CH"_4)/(16.04cancel("g CH"_4))) = color(red)(0.1247 color(red)("mol CH"_4

Now, we can use Avogadro's number to convert from moles to molecules of methane:

color(red)(0.1247)cancel(color(red)("mol CH"_4))((6.022xx10^23color(white)(l)"molecules CH"_4)/(1cancel("mol CH"_4)))

= color(green)(7.508xx10^22 color(green)("molecules CH"_4

Finally, we use the atomic number of each element to find the total number of protons; we know:

$\text{carbon} = 6$

$\text{hydrogen" = 1 xx overbrace(4)^"four atoms per molecule} = 4$

For a total of

6+4=ul(10 $\text{protons}$

per molecule.

Therefore,

color(green)(7.508xx10^22)cancel(color(green)("molecules CH"_4))((10color(white)(l)"protons")/(1cancel("molecule CH"_4))) = color(blue)(ul(8xx10^23color(white)(l)"protons"#

rounded to $1$ significant figure.