Question

In the following reaction, how many grams of nitroglycerin C3H5(NO3)3 will decompose to give 120 grams of water?

Answer 1

1) Chemical equation

4C3H5(NO3)3(l) 12CO2(g) + 6N2(g) + 10H2O(g) + O2(g)

$4C_3H_5(NO_3)_3(l) -\ \textgreater \ 12CO_2(g) + 6N_2(g) + 10H_2O(g) + O_2(g)$

2) Molar ratios

4 mol C3H5(NO3)3 : 10 mol H2O

3) Convert grams of water into number of moles:

numer of moles = mass in grams / molar mass = 120 g / 18.0158 g/mol =

number of moles = 6.66 moles H2O.

4) use proportion and solve for x

4 mol C3H5(NO3)3 / 10 mol H2O = x / 6.66 mol H2O

=> x = 6.66 mol H2O * 4 mol C3H5(NO3)3 / 10 mol H2O = 2.66 mol C3H5(NO3)3

5) Convert 2.66 mol C3H5(NO3)3 into grams

mass in grams = molar mass * number of moles = 227.0995 g * 2.66 mol = 605.07 g

Answer: 605.07 g