Why is it important to give the physical states of the reactants and products when giving an equation ofΔH

Copper has been used for thousands of years, either as a pure metal or in alloys. It is frequently used today in the production of wires and cables. Copper can be obtained through smelting or recycling. Determine the energy associated with each of these processes in order to recycle 1.40 mol Cu. The smelting of copper occurs by the balanced chemical equation: CuO(s) +CO(g) → Cu(s) +CO,(g) where AHtCuo is = - 155 kJ/mol. Assume the process of recycling copper is simplified to just the melting of the solid Cu starting at 25°C. The melting point of Cu is 1084.5°C with AH®fus = 13.0 kJ/mol and a molar heat capacity, CPCU = 24.5 J/mol:°C.

A gaseous system has 71 J of work done on it by surroundings and increases its internal energy by 69 J. Calculate the amount of heat associated with this scenario. 140 J of heat is released by the system. 2 J of heat is released by the system. The heat of the system remains constant. 2 J of heat is absorbed by the system. 140 J of heat is absorbed by the system.

The complete combustion of salicylic acid releases 21.90 kJ of energy per gram of salicylic acid.In a particular bomb calorimeter (initially at room temperature), the combustion of 0.2745 g of salicylic acid, in the presence of excess oxygen, causes the temperature of the calorimeter to rise by 1.85 °C.When a 0.2999-g sample of an unknown organic substance is similarly burned in the same calorimeter, the temperature rises by 3.59 °C.What is the energy of combustion per unit mass of the unknown substance?

As a system increases in volume, it absorbs 55.0 J of energy in the form of heat from the surroundings. The piston is working against a pressure of 0.540 atm. The final volume of the system is 58.2 L. What was the initial volume of the system if the internal energy of the system decreased by 103.4 J?

Consider the following formation reaction.   Ni + 4C + 2O2 → Ni(CO)4 ΔH = -607kJ   What mass of carbon reacts if 45.5 kJ of energy is released?

A particular container holds 3.77 mol of neon gas. The volume of this container can be altered by sliding a piston in or out. The volume is changed from 8.60 L to 12.20 L while at the same time the temperature is changed from 303 K to 345 K. The molar heat capacity, Cym, for neon is 12.47 J/(mol · K). Assume that this value will not change over the given temperature range. What is the change in entropy for the gas? AS = J/K TOOLS x10 MacBook Pro

When a solid dissolves in water, heat may be evolved or absorbed. The heat of dissolution (dissolving) can be determined using a coffee cup calorimeter. In the laboratory a general chemistry student finds that when 3.95 g of CuCl2(s) are dissolved in 108.60 g of water, the temperature of the solution increases from 23.05 to 26.27 °C. The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.86 J/°C. Based on the student's observation, calculate the enthalpy of dissolution of CuCl,(s) in kJ/mol. Assume the specific heat of the solution is equal to the specific heat of water. AHdissolution kJ/mol

The combustion of 2.495 g of propanol (C3H7OH) increases the temperature of a bomb calorimeter from 298.00 K to 302.76 K.The heat capacity of the bomb calorimeter is 17.59 kJ/K. Determine Δ? for the combustion of propanol to carbon dioxide gas and liquid water.