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Flashcards in Module 5 Deck (43):
1

How do you calculate rate and what are the units?

Change in concentration / change in time

Mol dm-3 s-1

2

When is a reaction of zero order?

When the concentration of the reactant has no effect on the rate

3

When is a reaction first order?

When the rate depends on its concentration raised to the power of one

If concentration is tripled the rate is tripled

4

When is a reaction second order?

When the rate depends on its concentration raised to the power of two

If the concentration is tripled the rate increases by a factor of 9

5

What is the rate equation?

Rate = k [A]^order [B]^order

6

How do you calculate the overall order of reactants?

Sum of orders with respect to each reactant

7

What is the shape of a zero order graph?

Straight line with negative gradient

The gradient is equal to the rate constant, k

8

What is the graph of a first order reactant?

A downward curve with a decreasing gradient over time

The concentration of the reactant to halve is constant (half-life)

9

What is the shape of a graph with second order?

A downward curve, steeper at the start but tails of slower than a first order curve

10

What is the gradient of a concentration time graph?

Rate

11

What is the rate determining step?

The slowest step in the sequence

12

What happens to the Boltzmann distribution when temperature is increased?

It shifts to the right, increasing the proportion of particles that exceed the activation energy

13

What is the Arrhenius equation?

k = A e^(-Ea/RT)

A = pre-exponential factor(frequency factor)
Ea = activation energy
R = gas constant
T = temperature in kelvin

14

What is the gradient of a ln k - 1/T graph?

-Ea/R

15

What is the y intercept of a ln k - 1/T graph?

ln A

16

What is Kc?

Equilibrium constant

Kc = [concentration of products]^number of moles / [concentration of reactants]^number of moles

17

What is a homogeneous equilibrium?

Contains an equilibrium species that all have the same state or phase

18

What is a heterogeneous equilibrium?

Contains equilibrium species that have different states or phases

19

What is the mole fraction?

Of A = moles of A / total moles in a gas mixture

20

What is the partial pressure of A?

Mole fraction of A x total pressure

21

What is Kp?

The equilibrium constant

Kp = partial pressure of products^number of moles / partial pressure of reactants^number of moles

22

What are the units for partial pressure?

Pa or kPa or atm

23

What happens to the position of equilibrium when the concentration of a species is increased?

Shifts in the direction that reduces the concentration

24

What happens to the position of equilibrium when the pressure is increased?

Shifts towards the side with fewer gaseous molecules

25

What happens to the position of equilibrium when the temperature is increased?

Shifts in the endothermic direction

26

What is the only factor which affects K?

Temperature

27

What happens to the equilibrium constant, K, when temperature increases in an exothermic reaction?

Decreases

Yield decreases

28

What is a brønsted lowry acid?

A proton donor

29

What is a Brønsted-Lowry base?

A proton acceptor

30

What is a conjugate acid-base pair?

Contains two species that can be interconverted by transfer of a proton

31

What is a mono basic acid?

One hydrogen ion can be replaced per molecule in an acid-base reaction

32

Acid + metal =

Salt + hydrogen

33

Acid + carbonate =

Salt + water + carbon dioxide

34

Acid + base =

Salt + water

35

Acid + alkali =

Salt + water

36

What is the pH of an acid?

0

37

What is the pH of an alkali?

14

38

What will pH be if [H+] is low?

A high value

39

What is the relationship between pH and [H+]?

pH = -log[H+]

40

What is the relationship between [H+] and [HA] for a strong acid?

[H+] = [HA]

41

For what type of acid does [H+] = [HA]?

A strong acid

42

How do you calculate pKa?

pKa = -logKa

43

What is the general form for the dissociation of any weak acid?

HA <=> H+ + A-