Calculations
What is the enthalpy change of the following reaction?
CO(g) + 2 H2(g) → CH3OH(l) + 64.3 kJ
-64.3 kJ
What is labeled wrong with this Chat GPT generated potential energy diagram?
The enthalpy change is actually 40 kJ, the activation energy is 75 kJ, the units should be in kJ not kJ/mol
The amount of energy required to form one mole of a compound.
enthalpy of formation
What do we call the equation that we want the other equations to match when working with Hess’s Law?
target equation
What does exothermic mean?
the reaction releases energy
Radon has a specific heat capacity of 9.4 J/g*oC. If the temperature of a 34 g sample is heated by 25 oC how much thermal energy (q) was transferred to radon?
7990 J
For this diagram, what is the enthalpy change?
200 kJ
A chemical system in which matter cannot flow into or out of, but energy can.
closed system
What is the equation used to find enthalpies using standard ethalpies of formation?
∆H = ∑n∆Hof(products) - ∑n∆Hof(reactants)
How does a catalyst affect the rate of reaction?
It increases the rate by lowering the activation energy.
What would the final temperature be if 1000 J of heat were transferred into 30.0 g of water initially at 15oC?
22.974 oC
What is the activation energy?
300 kJ
What is an endothermic reaction?
a reaction that requires energy or takes in energy from the surroundings
What is the standard enthalpy of formation of an element already in its standard state?
0, nothing
What lab instrument can be used to measure the intensity of colour produced in a reaction?
spectrophotometer
Use standard enthalpies of formation to calculate the enthalpy change of the following reaction: 2 NO(g) + O2(g) --> 2 NO2(g)
NO (g) = +90.3 kJ/mol O2(g)= 0 kJ/mol NO2(g)=+33.1 kJ/mol
-114.4 kJ
What is the potential energy of the activated complex?
400 kJ
The average kinetic energy of the particles in a sample of matter
temperature
What is the correct equation of standard formation of propanol (C3OH8)?
3C(s) + 4H2(g) + ½O2(g) 🡪 C3OH8(g)
Where did Mrs K go to high school?
Abu Dhabi, UAE
Using Hess's Law, what is the enthalpy change of the target reaction C(s) + 2 H2(g) 🡪 CH4(g)
C(s) + O2(g) 🡪 CO2(g) ∆H1 = -393.5 kJ
H2(g) + 1/2 O2(g) 🡪 H2O(l) ∆H2 = -285.8 kJ
CH4(g) + 2 O2(g) 🡪 CO2(g) + 2 H2O(l) ∆H3 = -890.3 k
-74.8 kJ
What is an activated complex?
a short-lived unstable combination of reactants that have enough energy to undergo collisions.
The quantity of heat required to raise the temperature of a unit mass of a substance by 1oC or 1K.
specific heat capacity
reactant, endothermic reaction requires heat
Explain how increasing temperature increases the rate of reaction.
Increasing temperature provides the reactants with more kinetic energy thus increasing the rate of collisions so it is more likely that reactants will meet to form products.