Chemistry: Algebra Combining Equations [Enthelpy]

In summary, the conversation is about a student seeking help with a lab analysis question that involves using Hess's Law to algebraically combine equations and their corresponding change in enthalpy values. The student is unsure of how to approach the problem and asks for clarification on whether to change the signs and add the equations together to find the enthalpy of equation 1.
  • #1
intellekt
3
0
Hi, I am stuck on this one question for a lab analysis I am doing. I missed the class where the teacher explained this and a lot more stuff. I also recall a question like this on a test I wrote on friday:smile:

Anyway here it is:

Algebraically combine equations (2), (3), and (4) and their corresponding [Change in Enthalpy] values, to get (1) and [Change in Enthalpy] of combustion of magnesium.

I just need to know how to do it, I can plug in the values after right?

Let me know! thanks in advance!
 
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  • #2
Have you learned about Hess's Law?
"[URL
Your question requires a direct application of Hess's Law.
 
Last edited by a moderator:
  • #3
Ya I have learned Hess' law but I'm still unsure...

So do I change the signs then add them together to get the enthalpy of equation 1?
 
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FAQ: Chemistry: Algebra Combining Equations [Enthelpy]

1. What is enthalpy in chemistry?

Enthalpy is a thermodynamic quantity that describes the total amount of energy in a system. In chemistry, it is often used to measure the heat of a reaction or the heat absorbed or released during a chemical process.

2. How do you calculate enthalpy change?

To calculate enthalpy change, you can use the equation: ΔH = Hfinal - Hinitial. This means you subtract the initial enthalpy from the final enthalpy to find the change. The units for enthalpy are usually kilojoules (kJ).

3. What is the relationship between enthalpy and energy?

Enthalpy and energy are closely related, as enthalpy is a measure of the total energy in a system. However, enthalpy also takes into account the pressure, volume, and temperature of a system, while energy does not. Enthalpy is often used in chemical reactions because it accounts for the energy changes in the system.

4. How does algebra apply to combining equations in chemistry?

Algebra is used in chemistry to combine equations, which involves manipulating and rearranging equations to find a desired result. This can be useful when trying to find the enthalpy change of a reaction or when solving for an unknown variable in a chemical equation.

5. What are some practical applications of enthalpy in chemistry?

Enthalpy is used in many practical applications in chemistry, such as in the production of energy, the design of chemical processes, and the study of chemical reactions. It is also used in industries such as food production, pharmaceuticals, and materials science to better understand and control chemical reactions and processes.

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