Question #cd3c6

3 Answers
Feb 3, 2018

It will be a .1 " M" solution of both Na^+ and Cl^- ions.

Explanation:

By salt, I assume you mean common table salt, NaCl. You are given that you have .2 moles of salt, thus you have .2" mol " Na^+ "and " .2 " mol " Cl^-.

Molarity is defined as the moles of a substance per Liter, so the molarity of the solution for both Na^+ and Cl^- is as follows:

(.2" moles")/(2" Liters") = .1 ("mol")/("Liter") = .1 " M"

Feb 3, 2018

"0.1 mol L"^(-1)

Explanation:

All you need to know here is that molarity is defined as the number of moles of solute present for every "1 L" of the solution.

This means that in order to find the molarity of a given solution, you must determine how many moles of solute are present for every "1 L" of this solution.

In your case, you know that 0.2 moles of solute are dissolved in "2 L" of the solution. Your goal here is to figure out how many moles of solute must be present in "1 L" of this solution in order to have a solution of equal concentration to the one that contains 0.2 moles of solute in "2 L" of the solution.

"? moles solute"/"1 L solution" = "0.2 moles solute"/"2 L solution"

Rearrange to get

? = (1 color(red)(cancel(color(black)("L solution"))))/(2color(red)(cancel(color(black)("L solution")))) * "0.2 moles solute"

? = color(darkgreen)(ul(color(black)("0.1 moles solute")))

The answer is rounded to one significant figure.

So, you can say that this solution will have a molarity of "0.1 mol L"^(-1), which implies that "1 L" of the solution will contain 0.1 moles of solute.

Feb 3, 2018

The molarity of the salt solution is "0.1 M".

Explanation:

"molarity"=("moles of solute")/("1 L of solution")

There are "0.2 mol of salt" dissolved in "2 liter of salt solution".

"molarity"=("0.2 mol salt")/("2 L")="0.1 mol salt/L = 0.1 M salt"