Question

A solution of salt and water contains 70 grams of water per 140 milliliters of the solution. If 1 mole of water weighs 16 grams, _____ moles of water would be present in 35 milliliters of the solution. [Round off your answer to two decimal places]

Answer 1

You might want to put this in the chemistry section bud.

Answer 2

I will help you out however.

Answer 3

really? its a math problem though..

Answer 4

Thanks i would appreciate that.

Answer 5

We have 70 grams of water/140 mL of solution. 1 mole of water weighs 16 grams. x moles of water would be in 35 mL of solution.

Start off by figuring out how grams of water you need for 16 mL of solution.
70 g/140 mL=x g/35 mL
x=17.5 g I believe
Now that we know we need 8 grams for 16 mL of water, we simply must convert it to moles with some stoichiometry.

17.5 g*(1 mol/16 g)=1.09 moles
Notice how I multiplied by what is called the molar mass ratio. The grams canceled out and I am left with moles.

Answer 6

would you need to round 1.09?

Answer 7

Isn't that what the question says to do?

Answer 8

what would u round to