Measurements show that the enthalpy of a mixture of gaseous reactants increases by 253. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -171. kJ of work is done on the mixture during the reaction. Calculate the change in energy of the gas mixture during the reaction. Be sure your answer has the correct number of significant digits. O exothermic Is the reaction exothermic or endothermic? O endothermic

None

disilicon pentaselenide,  is it ionic or covalent?

It takes 183 J of energy to raise the temperature of 118.4 g of zinc from 23.61°C to 27.58°C. Calculate the specific heat capacity and the molar heat capacity of zinc.

Which of the following is a statement of Hess's law?     If a reaction is carried out in a series of steps, the ΔH for the reaction will equal the sum of the enthalpy changes for the individual steps. The ΔH for a process in the forward direction is equal in magnitude and opposite in sign to the ΔH for the process in the reverse direction. The ΔH of a reaction depends on the physical states of the reactants and products. If a reaction is carried out in a series of steps, the ΔH for the reaction will equal the product of the enthalpy changes for the individual steps. The ΔH for a process in the forward direction is equal to the ΔH for the process in the reverse direction.

A 2.673 g sample of a new organic material is combusted in a bomb calorimeter. The temperature of the calorimeter and its contents increase from 25.03 ∘C to 28.80 ∘C. The heat capacity (calorimeter constant) of the calorimeter is 31.65 kJ/ ∘C, what is the heat of combustion per gram of the material?

100 g of hot metal was put in 222.2 g of water in a container. Both the container and the water are at 20 deg C. Cp of water is 4.184 J K−1 g −1 and Cp of metal is 0.4444 J K−1 g −1. 2.222 kJ K−1 is the heat capacity of the container. 22 C is the final temperature of the metal, water and the container. Determine the  initial temperature of the metal.

Measurements show that the energy of a mixture of gaseous reactants decreases by 206. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -145. kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction. Be sure your answer has the correct number of significant digits. O exothermic Is the reaction exothermic or endothermic? O endothermic

A 3.623 g sample of a new organic material is combusted in a bomb calorimeter. The temperature of the calorimeter and its contents increase from 23.53 ∘C to 30.40 ∘C. The heat capacity (calorimeter constant) of the calorimeter is 35.71 kJ/ ∘C, what is the heat of combustion per gram of the material?

Measurements show that the energy of a mixture of gaseous reactants increases by 396. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 122. kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction. Be sure your answer has the correct number of significant digits. O exothermic Is the reaction exothermic or endothermic? O endothermic