In the reaction 2NaOH+H_2SO_4 -> 2H_2O+Na_2SO_42NaOH+H2SO42H2O+Na2SO4, how many grams of sodium sulfate will be formed if you start with 200.0 grams of sodium hydroxide and you have an excess of sulfuric acid?

2 Answers
Mar 15, 2016

Use the mole analogy of the reactant with the product. and substitute with the mole definition.

Answer is 355 grams.

Explanation:

Given the molecular weights:

Mr_(NaOH)=40 g/(mol)MrNaOH=40gmol
Mr_(Na_2SO_4)=142 g/(mol)MrNa2SO4=142gmol

The analogy of the moles will be held constant:

n_(NaOH)/n_(Na_2SO_4)=2/1nNaOHnNa2SO4=21

n_(NaOH)/n_(Na_2SO_4)=2nNaOHnNa2SO4=2

For each one, substitute:

n=m/(Mr)n=mMr

Therefore:

n_(NaOH)/n_(Na_2SO_4)=2nNaOHnNa2SO4=2

(m_(NaOH)/(Mr_(NaOH)))/(m_(Na_2SO_4)/(Mr_(Na_2SO_4)))=2mNaOHMrNaOHmNa2SO4MrNa2SO4=2

(200/40)/(x/142)=220040x142=2

(200*142)/(40x)=220014240x=2

200*142=2*40x200142=240x

x=(200*142)/(2*40)=(100*142)/40=10*142/4=1420/4=x=200142240=10014240=101424=14204=

=710/2=355grams=7102=355grams (or just use a calculator)

Mar 15, 2016

Through conversion method using mole ratio and formula masses the answer is 355355 g of Na_2SO_4Na2SO4

Explanation:

  1. Equation is already balanced, therefore what you need to find are the formula masses of the involved compounds, NaOHNaOH and Na_2SO_4Na2SO4;
  2. Once known, start the calculation by converting 200200 g NaOHNaOH to mole NaOHNaOH by multiplying it with the ratio of the formula mass of NaOHNaOH;
  3. The result from the above calculation, will then be multiplied by the mole ratio of Na_2SO_4Na2SO4 and NaOHNaOH, which is (1 mol Na_2SO_4)/(2 mol NaOH)1molNa2SO42molNaOH;
  4. Since, we are asked to find the mass of Na_2SO_4Na2SO4 formed in this reaction, we need to multiply the answer of step 3step3 to the ratio of the formula mass of Na_2SO_4Na2SO4.
  5. Per calculation, the answer in mass is 355355 grams of Na_2SO_4Na2SO4.