contestada

Given that cao(s) + h2o(l) → ca(oh)2(s), δh°rxn = –64.8 kj/mol, how many grams of cao must react in order to liberate 525 kj of heat?

Respuesta :

superman1987

Answer:

454.3 g.

Explanation:

  • From the given data:

1.0 mol of CaO liberates → – 64.8 kJ.

??? mol of CaO liberates → - 525  kJ.

∴ The no. of moles needed = (1.0 mol)(- 525 kJ)/(- 64.8 kJ) = 8.1 mol.

∴ The no. of grams of CaO needed = no. of moles x molar mass = (8.1 mol)(56.077 g/mol) = 454.3 g.

dsdrajlin

Considering the thermochemical equation for the synthesis of calcium hydroxide, 454 g of CaO must react to liberate 525 kJ of heat.

What is a thermochemical equation?

A thermochemical equation is a balanced stoichiometric chemical equation that includes the enthalpy change, ΔH.

  • Step 1. Write the thermochemical equation for the synthesis of calcium hydroxide.

CaO(s) + H₂O(l) → Ca(OH)₂(s),    ΔH°rxn = –64.8 kJ/mol

  • Step 2. Calculate the moles of CaO needed to release 525 kJ of heat.

According to the thermochemical equation, 64.8 kJ are released upon the reaction of 1 mole of CaO.

525 kJ × 1 mol CaO/64.8 kJ = 8.10 mol

  • Step 3. Convert 8.10 moles of CaO to grams

The molar mass of CaO is 56.08 g/mol.

8.10 mol × 56.08 g/mol = 454 g

Considering the thermochemical equation for the synthesis of calcium hydroxide, 454 g of CaO must react to liberate 525 kJ of heat.

Learn more about thermochemical equations here: https://brainly.com/question/17612990

Otras preguntas