**Chemical Reaction and Heat Exchange Analysis** Consider the reaction: \[ 2 \text{Fe}_2\text{O}_3 \rightarrow 4 \text{Fe} + 3 \text{O}_2 \] \[ \Delta H^\circ_{\text{rxn}} = +824.2 \, \text{kJ} \] The decomposition of 79.0 g of Fe₂O₃ results in: - ○ the release of 32600 kJ of heat. - ○ the absorption of 204 kJ of heat. - ○ the release of 204 kJ of heat. - ○ the absorption of 408 kJ of heat. - ○ the absorption of 32600 kJ of heat. - ○ the release of 408 kJ of heat. **Analysis of ΔH (Enthalpy Change):** - The positive ΔH value indicates an endothermic reaction, meaning that the reaction absorbs heat. **Educational Explanation:** - To find the heat change for the decomposition of 79.0 g of Fe₂O₃, the molar mass of Fe₂O₃ should be used to convert the grams to moles. The stoichiometry of the balanced equation and the given ΔH can then be used to determine the heat absorbed or released for this specific mass of Fe₂O₃.

The reaction: 2 Na + Cl2 --> 2 NaCl + 822 kJ, isGroup of answer choices exothermic protothermic isothermic endothermic

Suppose a pair of chemical compounds A and B can react in two different ways: A+B C Reaction 1 gives product C. A+B D Reaction 2 gives product D. The following facts are known about the two reactions: . Both reactions are exothermic, but the heat of reaction of Reaction #1 is larger. • If a reaction vessel is charged ("filled") with A and B, then at first C is produced faster than D. Use these facts to sketch a qualitative reaction energy diagram for both reactions. Note: because these sketches are only qualitative, the energies don't have to be exact. They only have to have the right relationship to each other. For example, if one energy is less than another, that fact should be clear in your sketch. energy ^ A + B Reaction 1 reaction coordinate energy ^ A+B Reaction 2 reaction coordinate X Ś

A 6.57 g sample of an unknown salt (MM = 116.82 g/mol) is dissolved in 150.00 g water in a coffee cup calorimeter. Before placing the sample in the water, the temperature of the salt and water is 23.72°C. After the salt has completely dissolved, the temperature of the solution is 28.54°C. L L L L What is the total mass inside the calorimeter in grams? What is the change in temperature, in °C, inside the calorimeter? Was the dissolution process endothermic or exothermic? What quantity of heat, in J, was gained by the solution? Assume the specific heat of the solution is the same as water, 4.184 J/g. °C. What is the total heat for the dissolution reaction of the 6.57 g of salt? What quantity in moles of the unknown salt were used in the reaction? >