1.9 mol HCl and 2.9 mol NaOH react according to the equation HCl + NaOH −→ NaCl + H2O

Question

Calculate the amount of H2O formed

Answer 1

First we need to check that the equation is balanced. Since the equation is already balanced, we need to know which reagent is the limiting reagent. The limiting reagent is the reagent with least amount of moles used in the reaction; so we know that HCl is the limiting reagent. We can use the coefficients (which are 1 because there are none written) to know that we have a 1:1 ratio of HCl and H2O. Therefore we have 1.9 moles of H2O produced. Then using the molar mass (found by using the periodic table), we calculate the number of grams of H2O. The molar mass of H2O is 18 g/mole. We then do 1.9*18=34.2 grams of H2O.

Answer 2

Hi Hilarfy L.,

Your equation is already stoichiometrically balanced. So just look which ingredient is limiting -- it's the HCl -- and since 1 mol H2O is made for each mol HCl neutralized, that's 1.9 mol H2O.

Right?