Answer:
a. 17.8 grams
Step-by-step 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)