Energy (4) Flashcards Preview

Chemistry GCSE > Energy (4) > Flashcards

Flashcards in Energy (4) Deck (12)
Loading flashcards...
1
Q

What do energy level diagrams show

A

Whether it’s Exo- or Endo-thermic

2
Q

In exothermic reactions ΔH is negative - this means that the products are at a ___________ energy than the reactants

A

Lower

3
Q

In an energy level diagram, the difference in height represents the energy _________ _____ in the reaction (per mole)

A

Given out

4
Q

What does the initial rise in the line of an energy level diagram represent

A

The energy needed to break the old bonds. The activation energy

5
Q

In endothermic reactions ΔH is positive because the products are at a ___________ energy than the reactants,

A

Higher

6
Q

The activation energy is lowered by ___________

A

Catalysts

7
Q

What does the activation energy represent

A

The minimum energy needed by reacting particles for the reaction to occur

8
Q

How does a catalyst make reactions happen faster

A

By providing an alternative pathway with a lower activation energy

9
Q

How is a catalyst represented on an energy level diagram

A

A lower curve on the diagram which shows that less initial energy is needed for the reaction to begin

10
Q

Even if a catalyst is used in the reaction, the overall ___________ stays the same

A

ΔH enthalpy.

11
Q

In bond energy calculations, if your final answer is negative then the ΔH is ____________ so the reaction must be ______________

A

Negative

Exothermic

12
Q

In bond energy calculations, if your final answer is positive then the ΔH is ____________ so the reaction must be ______________

A

Positive

Endothermic