Question #0ac55

1 Answer
Mar 18, 2017

"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.