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Cao(s) reacts with water to form ca(oh)2(aq). if 6.50 g cao is combined with 99.70 g h2o in a coffee cup calorimeter, the temperature of the resulting solution increases from 21.7 °c to 43.1 °c. calculate the enthalpy change for the reaction per mole of cao. assume that the specific heat capacity of the solution is 4.18 j/g×k.

Respuesta :

I am not sure but I think it is 47.28.
pstnonsonjoku

The heat of reaction is -79.2 kJ/mol.

The equation of the reaction is;

CaO(s) + 2H2O(l) ------> Ca(OH)2(aq) + H2(g)

Number of moles of CaO =  6.50 g/56 g/mol = 0.12 moles

Number of moles of H2O =  99.70 g/18 g/mol = 5.53 moles

Temperature rise =  43.1 °C -  21.7 °C = 21.4  °C

Total mass of solution = 99.70 g + 6.50 g = 106.2 g

We must obtain the limiting reactant as follows;

1 mole of CaO reacts with 2 moles of H2O

0.12 mole of CaO reacts with 0.12 mole × 2 moles/1 mole = 0.24 moles

We can see that CaO is the limiting reactant.

Heat absorbed = 106.2 g ×  4.18 J/g-1K-1 × 21.4  °C = 9.5 kJ

Heat of reaction = -(9.5 kJ/0.12 moles) = -79.2 kJ/mol

Learn more: https://brainly.com/question/7558603

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