Question

Question #0ac55

Answer 1

`"1.4 L"`

Explanation:

For a given solution, we use molarity to express the number of moles of solute present for every `"1 L"` of solution.

In this case, a `"2.8-M"` solution must contain `2.8` moles of solute for every `"1 L"` of solution.

Now, solutions are homogeneous mixtures, which implies that they have the same composition throughout. Consequently, you can say that `4.00` moles of solute in an unknown volume of solution must be equivalent to `2.8` moles of solute in `"1 L"` of solution.

In other words, you can use the molarity of the solution as a conversion factor to determine the volume of the solution that must contain `4.00` moles in order to have a solution that would contain `2.8` moles of solute in `"1 L"` of solution

`4.00 color(red)(cancel(color(black)("moles solute"))) * "1 L solution"/(2.8color(red)(cancel(color(black)("moles solute")))) = color(darkgreen)(ul(color(black)("1.4 L solution")))`

The answer is rounded to two sig figs, the number of sig figs you have for the molarity of the solution.