Question

Can someone pls help me with number 8? Thanks ~

Answer 1

So we can use the equation: $M_{1}V_{1}=M_{2}V_{2}$

where M is the concentration and V is the volume in liters.

We can then solve for how much of the stock solution we are going to put into the new solution:

$(5M)(V_{2})=(1.5M)(0.5L)$

Then we can solve for V_{2}:

$V_{2}=\frac{(1.5M)(0.5L)}{5M}=0.15L$

So now we know that we need to use 150 mL of the stock solution in the new solution - and we know that the total volume of the new solution is 500 mL. So therefore the rest of the new solution should be water:

$500-150=350$

So the rest of the solution (350 mL) is water.