Liquid hydrogen peroxide, an oxidizing agent in many rocket fuel mixtures, releases oxygen gas on decomposition.
2 H2O2(l) 2 H2O(l) + O2(g) Hrxn = -196.1 kJ
How much heat is released when 529 kg H2O2 decomposes?
( ......... ) KJ
*note ..watch sig figs .
my work:
• 2 H2O2(l) => 2 H2O(l) + O2(g) ΔHrxn = -196.1 kJ
Moles of H2O2 = mass/molar mass
= 529,000/34 = 15558.82 moles of H2O2 release 196.1 kJ of heat
Total heat released = 15558.82/2 x196.1 = 1525542.301 = 1.52554 × 10^6
= 1.53 x 10^6 kJ (3 significant figures)
am I correct?
Yes, you are correct! Your calculation is accurate.
Yes, your calculation is correct. Here is the step-by-step explanation:
To find out how much heat is released when 529 kg of H2O2 decomposes, follow these steps:
1. Write the balanced equation for the reaction given:
2 H2O2(l) → 2 H2O(l) + O2(g) ΔHrxn = -196.1 kJ
2. Calculate the number of moles of H2O2:
Moles of H2O2 = mass/molar mass
mass = 529 kg
molar mass of H2O2 = 34 g/mol (grams per mole)
Convert kg to grams: 529 kg × 1000 g/kg = 529,000 g
moles of H2O2 = 529,000 g / 34 g/mol = 15558.82 moles
3. Use the stoichiometry of the reaction to determine the amount of heat released per mole of H2O2:
The balanced equation shows that 2 moles of H2O2 produce 196.1 kJ of heat. Since the reaction is balanced, this means that for every 2 moles of H2O2, 196.1 kJ of heat is released. Therefore, per mole of H2O2, the amount of heat released is 196.1 kJ / 2 = 98.05 kJ.
4. Calculate the total heat released:
Total heat released = moles of H2O2 × heat released per mole
= 15558.82 moles × 98.05 kJ/mole = 1525542.301 kJ
5. Apply significant figures:
The given question notes to consider significant figures. Since the result of the calculation has three significant figures, we round the answer to three significant figures as well. Therefore, the final answer is 1.53 × 10^6 kJ (in scientific notation) or 1,530,000 kJ (in standard notation).
So, you are correct, the amount of heat released when 529 kg of H2O2 decomposes is 1.53 × 10^6 kJ (rounded to three significant figures).