Worksheet: Molar Energy Units
In this worksheet, we will practice using Avogadro's number to convert between molar energies and the energies of single bonds.
What is Avogadro’s number to 3 significant figures?
Which of the following quantities of bonds requires the most energy to break?
The energy of the hydrogen–hydrogen bond in is 436 kJ/mol. Which of the following is an equivalent description of the bond energy in hydrogen?
- A436 kJ of energy is required to form the hydrogen–hydrogen bonds of hydrogen molecules.
- BFor every hydrogen–hydrogen bond in a hydrogen molecule formed, 436 kJ of energy is released.
- C436 kJ of energy is released when the hydrogen–hydrogen bonds of hydrogen molecules are broken.
- DFor every hydrogen–hydrogen bond in a hydrogen molecule broken, 436 kJ of energy is released.
- E436 kJ of energy is required to break the hydrogen–hydrogen bonds of hydrogen molecules.
What is the SI unit for energy?
- AJoule (J)
- BMole (mol)
- CWatt (W)
- DKilogram (kg)
- EElectron volt (eV)
The specific heat capacity of a substance is usually given in units of joules per gram per degree Celsius. From these units, which of the following statements best describes specific heat capacity?
- AThe amount of energy needed to raise the temperature of 1 gram of a substance by
- BThe temperature of a substance that is equal to the amount of energy multiplied by its mass
- CThe amount of substance that can be produced when one joule of energy is raised by
- DThe amount of energy formed when 1 gram of a substance reaches a specific temperature
- EThe mass of a substance needed to raise the temperature by
A single bond has an energy of . What is the molar bond energy for ? Give your answer to the nearest whole number.
It takes approximately J of energy to break all the bonds in a single molecule of methane, . What is the average molar bond energy for bonds? Give your answer to the nearest whole number.
4.6 g of a fuel is found to produce J of heat energy. If the of the fuel is 46 g/mol, what is the molar enthalpy change?
- A kJ/mol
- B kJ/mol
- C kJ/mol
- D kJ/mol
- E kJ/mol
Which of the following are units for the molar enthalpy change of a reaction, ?
It is estimated that the average adult should consume around 2,000 kcal per day to maintain a healthy lifestyle. What is this value in units of kilojoules?
A food manufacturer determines that the energy content of one slice of their new bread is 400 kJ. What value is this in kilocalories? Give your answer to 1 decimal place.
A chocolate bar is found to contain 228 kcal. What value is this in units of kilojoules? Give your answer to the nearest whole number.