Question #356ae

1 Answer
Jul 3, 2017

Here's what I got.

Explanation:

Since you didn't provide an actual volume for your target solution, let's take the easy route and calculate the mass of glucose needed to make "1 L"1 L of "1.4-M"1.4-M solution.

The thing to remember about molarity is that it represents the number of moles of solute present in "1 L"1 L of solution. In your case, a "1.4-M"1.4-M glucose solution will contain 1.41.4 moles of glucose for every "1 L"1 L of solution.

Now, you can use the molar mass of glucose to calculate the number of grams that would contain that many moles of glucose.

1.4 color(red)(cancel(color(black)("moles glucose"))) * "180.156 g"/(1color(red)(cancel(color(black)("mole glucose")))) = "250 g" -> rounded to two sig figs

You can thus say that a "1.4-M" glucose solution will contain "250 g" of glucose, the equivalent of 1.4 moles of glucose, for every "1 L" of solution.

You can use this information to figure out the mass of glucose that would be present in, for example, "0.5 L" of "1.4-M" solution.

0.5 color(red)(cancel(color(black)("L solution"))) * "250 g glucose"/(1color(red)(cancel(color(black)("L solution")))) = "130 g glucose " -> two sig figs