General Chemistry II: Enthalpy Change

What is the primary definition of energy in the context of thermodynamics?

The energy of random motion associated with temperature change
The energy resulting from the interaction of charged particles
The ability to cause motion of an object against a force
The capacity to do work or transfer heat (correct)

What is the equation that defines kinetic energy?

Ek = mv^2 (correct)
E = mc^2
Eel = Q1Q2 / d
Q = cd

What type of energy is associated with the interaction of charged particles?

Thermal energy
Electrostatic energy (correct)
Potential energy
Chemical energy

What occurs when bonds are formed in a chemical reaction?

Energy is evolved (D) Signup and view all the answers

What is the definition of heat in the context of thermodynamics?

The form of energy that brings about temperature change when transferred (D) Signup and view all the answers

What type of energy is stored within the structural units of chemical substances?

Chemical energy (C) Signup and view all the answers

What is the unit of heat capacity?

J/°C or J/K (B) Signup and view all the answers

What is the amount of heat energy required to raise the temperature of one gram of a substance by 1 °C?

Specific heat capacity (D) Signup and view all the answers

What is the formula to calculate the quantity of heat absorbed by an object?

heat = (mass) × (specific heat capacity) × (temp. change) (D) Signup and view all the answers

If 100 g of water requires 1000 J of heat energy to raise its temperature by 1 °C, how much heat energy would be required to raise the temperature of 200 g of water by 1 °C?

2000 J (B) Signup and view all the answers

Why does 1000 J of heat energy raise the temperature of 100 g of sand by 12 °C, but only raise the temperature of 100 g of water by 2.4 °C?

Because the heat capacity of an object depends on the type of material (D) Signup and view all the answers

What is the molar heat capacity of a substance?

The amount of heat energy required to raise the temperature of one mole of a substance by 1 °C (D) Signup and view all the answers

What is the specific heat of water in joules per gram-kelvin?

4.18 J/g-K (C) Signup and view all the answers

What is the equation that relates the heat transferred to the mass, specific heat, and temperature change?

q = m x Cs x ΔT (D) Signup and view all the answers

What is the purpose of using a coffee-cup calorimeter in this experiment?

To determine the enthalpy change for the reaction (D) Signup and view all the answers

What is the acid-base reaction that occurs when mixing HCl and NaOH?

HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq) (D) Signup and view all the answers

How is the total heat produced in the reaction calculated?

Using the equation q = m x Cs x ΔT (D) Signup and view all the answers

What is the first step in solving the problem of calculating the enthalpy change for the reaction?

Calculate the number of moles of HCl and NaOH involved (D) Signup and view all the answers

What is the temperature change in the reaction of the acid with the base?

6.5°C (A) Signup and view all the answers

What is the unit of the specific heat capacity Cs in the equation?

J/g–K (D) Signup and view all the answers

What is the value of the enthalpy change per mole of HCl in the reaction?

-54 kJ/mol (D) Signup and view all the answers

What is the significance of the negative sign of the enthalpy change ΔH?

The reaction is exothermic. (D) Signup and view all the answers

What is the purpose of the bomb calorimeter in measuring the enthalpy change of a reaction?

To measure the internal energy change of the reaction. (D) Signup and view all the answers

What is the relationship between the enthalpy change ΔH and the internal energy change ΔE in a bomb calorimeter?

ΔH is approximately equal to ΔE. (D) Signup and view all the answers

What is the product of the combustion of methylhydrazine?

N2(g), CO2(g), and H2O(l) (A) Signup and view all the answers

What is the initial temperature of the calorimeter in the experiment?

25.00 C (D) Signup and view all the answers

What is the heat capacity of the calorimeter?

7.794 kJ/ C (B) Signup and view all the answers

What is the temperature change of the calorimeter during the experiment?

14.50 C (D) Signup and view all the answers

What is the heat evolved for the combustion of the 4.00-g sample of methylhydrazine?

-113.0 kJ (D) Signup and view all the answers

What is the goal of the problem?

To calculate the heat of reaction for the combustion of a mole of CH6N2 (C) Signup and view all the answers