How do you convert Joules to KJ/mol?
The correct answer and explanation is:
To convert Joules (J) to kilojoules per mole (kJ/mol), follow these steps:
- Understand the Units:
- Joules (J) is the standard unit of energy, while kilojoules (kJ) is a larger unit where 1 kJ = 1000 J.
- The “per mole” part refers to the quantity of energy per mole of a substance, often used in thermodynamics to measure the energy change associated with chemical reactions.
- Conversion of Joules to Kilojoules:
- Since 1 kJ = 1000 J, to convert from Joules to kilojoules, divide the energy value in Joules by 1000.
- Incorporate the Per Mole:
- If you’re given an energy value in Joules and need to convert it to kJ/mol, it is crucial to ensure that the energy is expressed per mole. If you have the energy value for a reaction or substance, divide by the number of moles involved.
For example, if you have 5000 J of energy associated with 2 moles of a substance, the calculation for energy per mole in kJ/mol would look like this:
- First, convert 5000 J to kJ: 5000 J=50001000=5 kJ5000 \, \text{J} = \frac{5000}{1000} = 5 \, \text{kJ}
- Then divide by the number of moles: 5 kJ2 mol=2.5 kJ/mol\frac{5 \, \text{kJ}}{2 \, \text{mol}} = 2.5 \, \text{kJ/mol}
- General Formula:
- If you have a value in Joules for energy per mole and want to convert it to kJ/mol, use the formula: kJ/mol=Energy (J)1000×Moles\text{kJ/mol} = \frac{\text{Energy (J)}}{1000 \times \text{Moles}}
In summary, converting Joules to kJ/mol involves dividing the energy in Joules by 1000 to convert to kilojoules and ensuring the energy is expressed per mole. This is commonly done when discussing thermodynamic values for reactions.