Question

How many electrons are present in $1.6g$ of methane?

Answer 1

Each substance has its specific chemical and physical property. Chemical properties tell about the number of the electron, proton, reactivity, etc while physical property tells about its shape, size, weight, mass, etc.

Complete step by step answer:
Here, we will find the number of electrons in methane.
Methane - It is a very known chemical compound that formula is $C{H_4}$. According to its chemical formula, it has one carbon atom and four hydrogen atoms. And as we know that each atom of carbon contains $6$ electrons and each atom of hydrogen contains $4$. This means a total of $10$ electron present in one molecule of methane.
The atomic mass of carbon is $12$ and hydrogen is $1$.
But, according to the question, we have to find an electron present in $1.6g$ of methane.
So, here firstly find the molar mass of the methane $C{H_4}$
= $12 + 4$
= $16g\,mo{l^{ - 1}}$
here we get $16g$ of methane = $1\,mol$
number of moles = $\dfrac{{mass\,of \,substance}}{{mass\,of\,one\,mole}}$
= $\dfrac{{1.6}}{{16}}$
= $0.1\,mol$
now, find the total number of molecule in $0.1\,mol\,$ $C{H_4}$ using Avogadro numbers
= $0.1 \times 6.022 \times {10^{23}}$
= $6.022 \times {10^{22}}$
we have $10$ electrons in one molecule of methane.
now, find the number of electron in $1.6g$ of methane
=$10 \times 6.022 \times {10^{22}}$
= $6.022 \times {10^{23}}$ electron
Finally, we got the $6.022 \times {10^{23}}$ electron in $1.6g$ of methane.

Note:
Electron- It is a subatomic particle that symbol is ${e^ - }$ . It has a negative charge. Mass - It is a physical quantity of any substance that resists changing its position and speed. Its SI unit is the kilogram. Molar mass- It defines the mass of each substance in the compound. Avogadro Number - It is a constant number which defines the number of units in one mole of a substance.