Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chem Mod 3 > Enthalpy Changes > Flashcards

Enthalpy Changes Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What is the definition of an Enthalpy change?

A

A measure of the heat given out or taken in during a process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is it easier to use Enthalpy change as opposed to energy change?

A

Because Enthalpy allows for expansion of objects when they’re heated
The volume of the object must be fixed to measure energy change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an endothermic reaction?

A

A reaction that takes in heat energy so has a positive Enthalpy change
The surroundings will be cooler

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is an exothermic reaction?

A

A reaction which gives out heat energy
It will have a negative Enthalpy change
The surroundings will be warmer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the activation energy?

A

The energy required to break bonds in the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the standard conditions?

A

100 kPa

273K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How can you convert degrees C to K?

A

Add 273

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Enthalpy change of reaction?

A

The energy change associated with a given reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the Enthalpy change of formation?

A

The energy change that takes place when 1 mole of a compound is formed from its constituent elements in their standard state under standard conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the Enthalpy change of combustion?

A

The energy change that takes place when 1 mole of substance is completely combusted.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the Enthalpy change of neutralisation?

A

The energy change associated with the formation of one mole of water from a neutralisation reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the energy change when bonds are broken?

A

Endothermic,+, energy is taken in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the energy change when bonds are made?

A

Exothermic,-, this gives out energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How can you calculate Enthalpy change for a reaction using bond enthalpies?

A

The sum of bond enthalpies of reactants - the sum of bond enthalpies of products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does Hess’ law state?

A

The Enthalpy change in a chemical reaction is independent of the route it takes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are Enthalpy cycles?

A

Cycles which show alternative routes between reactants and products

17
Q

What is a homogeneous catalyst?

A

A catalyst for a reaction that’s in the same phase as the reactants eg . Liquid catalyst mixed with liquid reactants

18
Q

What is a heterogeneous catalyst?

A

A catalyst for a reaction that’s in a different phase to the reactants or a different liquid layer (immiscible liquid)

19
Q

How does a catalyst work?

A

Lowers the activation energy by providing an alternative route for the reaction to follow

Chem Mod 3 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions