Sodium hydroxide x sulfuric acid.

naoh + h2so4 → na2so4 + h2o

how many grams of na2so4 are produced from 10.0 grams of naoh?

a. 17.8 grams
b. 19.2 grams
c. 35.5 grams
d. 38.5 grams

a. 17.8 grams

Explanation:

To solve this we must first balance the equation.   So that each atom is on both sides of the equation in the same amount.

2 NaOH + H2SO4 → Na2SO4 + 2 H2O  

As a second step we have to calculate how many grams a mole of Na2SO4  and a mole of NaOH has.  What are the molecules that we are interested in calculating.

Na2SO4 = (23x2) + 32 + (16x4) = 142g / mol

NaOH = 23 + 16 + 1 = 40g / mol

Below the balanced equation we place the grams that will react. If we start with 2 moles of NaOH, 1 mole of Na2SO4 will form. (Notice that below NaOH I put 80g, this is because they are 2 moles. 1mol = 40g 2moles = 80g). And if we start with 10g how many grams of Na2SO4 are produced?

2 NaOH + H2SO4 → Na2SO4 + 2 H2O  

  80g  >  142g

  10g > X

Now we solve the rule of 3:

10g x 142g / 80g = 17.75g ≈ 17.8g  (by rounding we can approximate the result)