Question

In the gaseous state, chlorine exists as a diatomic molecule Cl2 (Molar mass = 70.9 g/mol). Calculate the number of moles of chlorine present in 130 g of chlorine gas.

Answer 1

3.67 mol Cl

Step-by-step explanation:

We need to convert g of Cl 2 to moles of Cl. First we divide 130 gCl2 by the molar mass (70.90 gCl2/mol) to find out how many moles of Cl2 do we have.

130 gCl2 x
`(1 mol Cl2 )/(70.90 gCl2)` = 1.83 mol Cl2

Then we need to convert 1.83 mol de Cl2 to moles of Cl. We have 2 moles of Cl in every Cl2 molecule so we just need to multiply by 2.

1.83 molCl2 x
`(2 molCl)/(1 molCl2)` = 3.67 molCl

Answer 2

There are 1.83 moles present in 130 g of chlorine gas.

Step-by-step explanation:

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

Then:

`x=(c*b)/(a)`

In this case, the rule of three can be applied as follows: if the molar mass indicates that 70.9 g of gaseous chlorine are present in 1 mol of the gas, 130 g will be present in how many moles of the gas?

`moles=(130 g*1mole)/(70.9g)`

moles=1.83

There are 1.83 moles present in 130 g of chlorine gas.