Chem 1 thermochemistry problem? Am I doing this right?

You can find out how much heat is evolved per 1 mole of Al by dividing the given value by 2.In summary, the reaction between aluminum and chlorine results in the formation of 2 moles of AlCl3 and releases 1408.4 KJ of heat. To determine how much heat is released for 5.00 g of Al, you would divide 1408.4 by 2 and then multiply by the number of moles of Al present.
  • #1
land_of_ice
137
0

Homework Statement



When aluminum reacts with chlorine
how much heat in KJ is released on reaction of 5.00 g of Al
for the following reaction:
2AL (s) + 3 CL2(g) ----->2AlCl3 (s)
delta h = -1408.4



Homework Equations





The Attempt at a Solution



Is it right if you start multiplying the delta H by the number of grams of Al , and by doing that by first converting grams of Al to moles? It's hard to tell you if you would divide by 2 at all? 2Al has something to do with it maybe?
 
Physics news on Phys.org
  • #2
Think about it this way - you are given amount of heat evolving per 2 moles of Al reacting.
 

1. What are the units for enthalpy change in a thermochemistry problem?

The units for enthalpy change in a thermochemistry problem are typically in joules (J) or kilojoules (kJ) for a single reaction or in joules per mole (J/mol) or kilojoules per mole (kJ/mol) for a molar enthalpy change.

2. How do I know if I am using the correct equation for a thermochemistry problem?

The correct equation for a thermochemistry problem can be determined by looking at the given information and identifying what is being asked for (i.e. enthalpy change, specific heat, etc.). Then, use the appropriate equation that relates the given information to the unknown variable.

3. Can I use the same equation for both exothermic and endothermic reactions?

Yes, the same equation can be used for both exothermic and endothermic reactions. However, the sign of the enthalpy change will be different for each type of reaction. For exothermic reactions, the enthalpy change will be negative, while for endothermic reactions, the enthalpy change will be positive.

4. How do I calculate the enthalpy change for a reaction with multiple products and reactants?

To calculate the enthalpy change for a reaction with multiple products and reactants, you can use the formula: ΔH = ΣnΔH(products) - ΣnΔH(reactants), where n represents the coefficients of each species in the balanced chemical equation.

5. What is the difference between heat and enthalpy in a thermochemistry problem?

Heat is a form of energy that is transferred between objects due to a difference in temperature. Enthalpy, on the other hand, is a measure of the total energy of a system, including both heat and work. In a thermochemistry problem, heat is typically the energy being transferred, while enthalpy is the total energy change of the system.

Similar threads

Chemistry Thermochemistry and the heat of complete combustion
    • Biology and Chemistry Homework Help
Replies
4
Views
1K
How to calculate heat from enthelpy of reaction
    • Biology and Chemistry Homework Help
Replies
5
Views
2K
Lewis structure and thermochemistry problems
    • Biology and Chemistry Homework Help
Replies
3
Views
2K
How much heat is evolved Thermochemistry Question
    • Biology and Chemistry Homework Help
Replies
4
Views
23K
Complete equation, then balance
    • Biology and Chemistry Homework Help
Replies
2
Views
2K
{Thermochemistry} Hess' law problem
    • Biology and Chemistry Homework Help
Replies
1
Views
2K
Percentage yield in a reaction problem
    • Biology and Chemistry Homework Help
Replies
4
Views
2K
Thermochemistry Problems: How Do I Solve These Two Heat Release Calculations?
    • Biology and Chemistry Homework Help
Replies
2
Views
5K
Solving Chemistry Enthalpy Homework: Step-by-Step Guide
    • Biology and Chemistry Homework Help
Replies
5
Views
2K
Calorimetry Problem: Calculate Change in Enthalpy
    • Biology and Chemistry Homework Help
Replies
16
Views
2K

Hot Threads

Recent Insights

Back
Top