# 5.1.1 - How Fast Flashcards

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1
Q

What is the reaction rate?

A

The change in the amount of reactants or products per unit time.

2
Q

What does the order of reaction tell you?

A

How the reactant’s concentration affects the rate.

3
Q

If the order is 0 what will happen to the rate if the concentration of the reactant is doubled?

A

Rate stays the same.

4
Q

If the order is 1 what will happen to the rate if the concentration of the reactant is doubled?

A

Rate also doubles.

5
Q

If the order is 2 what will happen to the rate if the concentration of the reactant is doubled?

A

6
Q

Rate =

A

k[A]^m [B]^n

7
Q

What is k, and what does it mean if it is bigger?

A

k is the rate constant and the bigger it is, the faster the reaction.

8
Q

What are m and n in the rate equation?

A

The orders of reaction with respect to reactant A and reactant B.

9
Q

On a concentration-time graph what does 0 order look like?

A

Straight line downwards (negative gradient) \

10
Q

On a concentration-time graph what does 1st order look like?

A

Curve downwards like a curly l.

11
Q

What is the half life of a reaction?

A

The time it takes for half of the reactants to be used up.

12
Q

What can you use the half life to calculate?

A

The order of the reactant, and the rate constant k.

13
Q

What happens to the half life in for 0 order?

A

The half life decreases.

14
Q

What happens to the half life for 1st order?

A

Same length.

15
Q

What happens to half life in a second order reaction?

A

Increases.

16
Q

What is the equation for calculating k using the half life? (Only 1st order)

A

k = In2 / half life

17
Q

What is the rate concentration graph for 0 order?

A

Straight horizontal line.

18
Q

What is the rate concentration graph for 1st order?

A

Straight line through origin, directly proportional.

19
Q

What is the rate concentration graph for 2nd order?

A

Curve upwards.

20
Q

What 4 ways can you measure the rate of reaction?

A
• measure the volume of gas evolved.
• measure the loss in mass of a gas evolved.
• use colorimetry to measure the colour change of a reaction.
• measure the pH change of a reaction.
21
Q

What is the rate determining step?

A

The slowest step in a reaction.

22
Q

How do you know what reactants are in the rds?

A

They are in the rate equation.

23
Q

How many moles of each reactant is in the rate equation?

A

You look at the order and that tells you how many moles of each of the reactant.

24
Q

What are intermediates?

A

Not shown in the overall equation as they are created and used up.

25
Q

What must occur to particles in order for a reaction to take place?

A

They must collide with energy equal to or above the activation energy and they must collide with the right orientation.

26
Q

What happens to the rate constant when the temperature increases?

A

It also increases.

27
Q

In the Arrhenius equation what is activation energy measured in?

A

J mol-1

28
Q

In the Arrhenius equation what is temperature measured in and how do you calculate this?

A

Kelvin (+273)

29
Q

When you log the Arrhenius equation what graph do you plot? What is the gradient and what is the y intercept?

A

ln against 1/T. -Ea/R. InA