If the molecular mass for a chemical is 153.82 g/mol and the enthalpy of formation is -135 kJ/mol, the heat change will be ____kJ when 10.0 g of this chemical is formed.
To calculate the heat change when 10.0 g of the chemical is formed, we need to convert the given information into the appropriate units and then use the molar mass of the compound.
1. Start by converting the molar mass of the chemical from g/mol to kJ/mol. To do this, you'll need to know the specific heat capacity of the compound.
2. The specific heat capacity can vary depending on the compound, so you'll need to find the specific heat capacity values of that particular compound. These values can be obtained from reliable sources such as textbooks or scientific databases.
3. Once you have determined the specific heat capacity, you can use the formula Q = mcΔT to calculate the heat change.
- Q: heat change (in kJ)
- m: mass of the compound (in grams)
- c: specific heat capacity (in kJ/(g·°C))
- ΔT: change in temperature (in °C)
Note: In this case, we are assuming that the change in temperature, ΔT, is negligible since the enthalpy of formation accounts for the heat change during the chemical's formation.
4. Use the molar mass of the compound to convert the mass from grams to moles. This can be done using the equation:
- Moles = mass (in grams) / molar mass (in g/mol)
5. Finally, use the heat of formation (given as enthalpy of formation) to calculate the heat change using the equation:
- Heat change = moles of compound formed * enthalpy of formation (in kJ/mol)
By following these steps, you can determine the heat change (in kJ) when 10.0 g of the chemical is formed.