Calculate the molar enthelpies of reaction occuring in parts A and B

In summary, the problem involves calculating the molar enthalpies of reaction for two parts, A and B, using the given masses and temperatures and the given amount of HCl used. The enthalpy change for Part A is -8 kJ and for Part B is -18 kJ. The correct equation to use is q=mcΔT.
  • #1
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Homework Statement


Part A:
Mass of Mg (s) = 0.31 g
Initial temperature of calorimeter contents = 24.1 C
Finial temperature of calorimeter contents = 36.8 C

Part B:
Mass of MgO (S) = 1.22 g
Initial temperature of calorimeter contents = 24.0 C
Finial temperature of calorimeter contents = 31. 9 C

100.0 ML of HCL used and -601.6 KJ/mol Mg reacted

Homework Equations


Calculate the molar enthalpies of reaction occurring Parts A and B.

The Attempt at a Solution


Part A (answer):
Enthalpy change of reaction = (chemical amount)(molar enthalpy of reaction)
=Enthalpy change or reaction= (0.31g)(1mol/24.31)(-601.1 kJ/mol/1mol)
= -7.665 kJ
= -8 kJ

Part B (answer):
Enthalpy change of reaction = (chemical amount)(molar enthalpy of reaction)
=Enthalpy change of reaction= (1.22g)(1mol/40.31g)(-601.1 kJ/mol/1mol)
= -18.19 kJ
= -18 kJ

Homework Statement


Homework Equations


The Attempt at a Solution

 
Last edited:
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  • #2
Shouldn't you use q=mcΔT?
 

Related to Calculate the molar enthelpies of reaction occuring in parts A and B

1. What is the molar enthalpy of reaction?

The molar enthalpy of reaction is the amount of energy released or absorbed during a chemical reaction per mole of reactant. It is typically measured in units of kilojoules per mole (kJ/mol).

2. How is the molar enthalpy of reaction calculated?

The molar enthalpy of reaction can be calculated by subtracting the sum of the molar enthalpies of the reactants from the sum of the molar enthalpies of the products. This can be determined by using experimental data or by using standard enthalpy of formation values for each compound.

3. What is the difference between molar enthalpy and standard enthalpy of reaction?

Molar enthalpy of reaction is the amount of energy released or absorbed per mole of reactant, while standard enthalpy of reaction is the molar enthalpy of reaction under standard conditions (25°C and 1 atm pressure). The standard enthalpy of reaction is often used for comparison between different reactions.

4. Why is it important to calculate the molar enthalpy of reaction?

Calculating the molar enthalpy of reaction allows us to understand the energy changes that occur during a chemical reaction. This information is crucial for determining the feasibility of a reaction, as well as predicting the amount of energy that may be released or required for a reaction to occur.

5. How does the molar enthalpy of reaction impact the overall thermodynamics of a system?

The molar enthalpy of reaction is a key factor in determining the overall thermodynamics of a system. The sign of the molar enthalpy of reaction (positive or negative) can indicate whether a reaction is exothermic (releases energy) or endothermic (absorbs energy). This information is important for understanding the stability and spontaneity of a reaction.

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