Question

Срочно!!! Известны тепловые эффекты следующих реакций: $2H_2 +O_2 =2 H_2O +572\textrm{кДж}$ $Ca + 0,5O_2 = CaO + 635,1\textrm{кДж}$ Определите тепловой эффект реакции гашения негашеной извести, если энтальпия образования гидроксида кальция равна -985,1кДж/моль

Answer 1

Ответ: 65 кДж тепловой эффект реакции гошения

Answer 2

Calculation of the Heat Effect of the Reaction

To determine the heat effect of the reaction, we need to use the enthalpy values provided for the reactions and apply the principle of Hess's law. Hess's law states that the overall enthalpy change of a reaction is independent of the pathway taken.

Let's break down the given reactions and their enthalpy values:

1. Reaction: $2H_2 + O_2 \rightarrow 2H_2O$ with a heat effect of 572 kJ 2. Reaction: $Ca + 0.5O_2 \rightarrow CaO$ with a heat effect of 635.1 kJ

Now, we need to determine the heat effect of the reaction of slaking unslaked lime (calcium oxide) with water. The enthalpy of formation of calcium hydroxide is given as -985.1 kJ/mol.

Calculation Steps:

1. We can reverse the second reaction to obtain the formation of calcium oxide from calcium and oxygen: $CaO \rightarrow Ca + 0.5O_2$ with a heat effect of -635.1 kJ (reversed sign)

2. We can multiply the first reaction by 0.5 to balance the number of moles of oxygen: $H_2 + 0.5O_2 \rightarrow H_2O$ with a heat effect of 286 kJ (572 kJ / 2)

3. We can multiply the second reaction by 2 to balance the number of moles of calcium: $2CaO \rightarrow 2Ca + O_2$ with a heat effect of -1270.2 kJ (2 * -635.1 kJ)

4. Finally, we can add the three reactions together to obtain the overall reaction: $2H_2 + 2CaO \rightarrow 2Ca + 2H_2O$ with a heat effect of -1270.2 kJ + 286 kJ = -984.2 kJ

Therefore, the heat effect of the reaction of slaking unslaked lime (calcium oxide) with water is approximately -984.2 kJ.

Please note that the provided enthalpy values and calculations are based on the information given in the question.