Answer:
607 ppm
Explanation:
In this case we can start with the <u>ppm formula</u>:

If we have a solution of <u>0.0320 M</u>, we can say that in 1 L we have 0.032 mol of
, because the molarity formula is:

In other words:


If we use the <u>atomic mass</u> of
(19 g/mol) we can convert from mol to g:
Now we can <u>convert from g to mg</u> (1 g= 1000 mg), so:

Finally we can <u>divide by 1 L</u> to find the ppm:

<u>We will have a concentration of 607 ppm.</u>
I hope it helps!
Answer:
13.94moles of Na₂O
Explanation:
The balanced reaction expression is given as:
4Na + O₂ → 2Na₂O
Given parameters:
Number of moles of O₂ = 6.97moles
Unknown:
Number of moles of Na₂O
Solution:
To solve this problem;
1 mole of O₂ will produce 2 moles of Na₂O ;
6.97 moles of O₂ will produce 6.97 x 2 = 13.94moles of Na₂O
Which of these measurements is expressed as three significant figures?
C. 4.20 g