General Chemistry I Lecture Notes Review

These flashcards cover key concepts from the lecture on Constant-Volume Calorimetry, Hess's Law, enthalpy changes, and specific reactions involving methylhydrazine and propane.

What is Constant-Volume Calorimetry used for?

It is used to measure the heat of reaction by observing temperature changes.

What is the equation for calculating heat of reaction in Constant-Volume Calorimetry?

qrxn = -Ccal × ΔT

What are the products when methylhydrazine (CH6N2) is combusted?

The products are N2(g), CO2(g), and H2O(l).

How do you calculate the heat of reaction for the combustion of 4.00 g of methylhydrazine?

Use the formula: qrxn = -Ccal × ΔT, where ΔT is the change in temperature.

What does Hess's Law state?

Hess's Law states that the total enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps.

What is the value of ΔH for the reaction C(s) + O2(g) → CO2(g)?

ΔH = -393.5 kJ.

What does the enthalpy of formation tell us?

It provides the change in enthalpy when one mole of a compound is formed from its elements in their standard states.

What is the standard enthalpy of formation for Acetylene (C2H2)?

226.7 kJ/mol.

How do you calculate the overall enthalpy change for a reaction using the standard enthalpies of formation?

Add the enthalpies of formation of products and subtract the enthalpies of formation of reactants.

What is the overall enthalpy change (ΔH) for the combustion of propane (C3H8)?

ΔH = -2220 kJ for the reaction C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l).