Question

Question #c644d

Answer 1

If `x=y`, then the expression `y=x` is also valid.
Proof.
`x=y`, taking `x` to RHS and `y` to LHS we obtain
`-y=-x`, Dividing both sides with `-1`, we obtain
`y=x`
`40mL`

Explanation:

Using the mole conservation equation
moles before dilution`=`moles after dilution
(we can also write moles after dilution`=`moles before dilution)
or `M_1V_1=M_2V_2`
`0.250 "mol"/"L"xxV_1=0.100"mol"/"L"xx100.0`
or `V_1=(0.100xx100)/0.250`
or `V_1=40mL`