I need some chemistry help,. I dont understand this question

Question

How many sodium ions are present in 325 mL of 0.850 M Na2SO4?

a. 5.12 x 10^23 Na ions

b. 8.32 x 10^22 Na ions

c. 1.02 x 10^24 Na ions

d. 3.33 x 10^23 Na ions

Anything will help!!!

Answer 1

First figure out how many moles there are.

A 0.850 M Na₂SO₄ means there are 0.85 moles per liter of water. Since you only have 325 mL, which is 0.325 liters, you can set up a proportion:

Cross multiply to solve for "x".

Then, realize that there are 2 sodium ions in every atom and there are 6.022 x 10²³ atoms per mole (Avogadro's number) so multiply your result by 2 and then by 6.022 x 10²³

Answer 2

Rosemary L.

Please don't submit your entire problem set to Wyzant Ask-an-Expert. Instead, become your own Expert: submit one problem of a given skill set (here, the skill set is converting units from mass to moles, and so on), wait for the answer (as you reread your textbook and try to solve yourself!), and then apply the technique you get in the answer you get (if any).

If you submit multiple querstions on the same area, you are LESS likely to have ANY of them answered, b/c a surveying "Expert" will conclude that you are not doing the above.

That being said, you are given: a volume, a molar concentration, and the desired output is numbers of sodium ions.

So -- use concentration and volume to calculate moles Na2SO4 (that's a multiplication; always include your units to make sure you didn't mess up!): 0.325L * 0.850 moles/L = (you do the math).

Next: knowing that # moles, how many moles of Na+ is that? There are TWO ions of Na in each mole of Na2SO4, so multiply by 2.

Now, how do you convert moles to particle numbers? (hint: Somebody's Number, 6.023 * 10^ ....?) multiply by that, and there you are.

-- Cheers, --Mr. d.