Question

A student added zinc powder to copper sulfate in a polystyrene cup and used the data she collected to calculate the enthalpy change of the reaction when 1 mole of copper sulfate reacts with 1 mole of zinc. However, she found that her value was lower than the published data for this reaction. Suggest two reasons why this might be.

a) Incomplete reaction
b) Measurement errors
c) Incorrect stoichiometry
d) Temperature fluctuations

Answer 1

Possible reasons for the student's lower calculated enthalpy change value include incomplete reaction, measurement errors, incorrect stoichiometry, and temperature fluctuations.

Step-by-step explanation:

There are several possible reasons why the student's calculated enthalpy change value is lower than the published data:

1. Incomplete reaction: The reaction may not have gone to completion, resulting in fewer moles of products being formed.
2. Measurement errors: Errors in measuring the quantities of reactants or products could contribute to inaccuracies in the calculated enthalpy change value.
3. Incorrect stoichiometry: If the stoichiometric coefficients in the balanced equation are incorrect, the calculated enthalpy change value will be different from the actual value.
4. Temperature fluctuations: Fluctuations in temperature during the reaction can affect the enthalpy change value calculated by the student.