Question

How many moles of `ZnCl` are in 100 mL of 0.300 M solution?

Answer 1

There are 0.030 mol of `ZnCl`

Explanation:

Let's get started by using the equation below:

Now, we identify our knowns and unknowns:

`color(purple)("Knowns:")`

• Volume
• Molarity

`color(blue)("Unknown:")`

• Moles of Solute

We are given the molarity and the volume of solution. The only issue is that the volume is given in mL instead of L. This issue can be fixed by using the following conversion factor:

`color(white)(aaaaaaaaaaaaaaaaaaaaa)1000mL = 1L`

Therefore, if we divide 100mL by 1000mL we will obtain a value of 0.100L.

Next, the equation has to be rearranged to solve for the moles of solute:

`color(red)("Moles of solute = Molarity x Liters of solution"`

Now, multiply 0.300 M by 0.100 L

`(0.300 mol)/cancelL xx0.100cancelL = "0.030 mol"`

Thus, there are 0.030 mol of `ZnCl`