2.1 Rates of a Reaction

Question 1

Collision Theory

Answer 1

Atoms must collide in a specific alignment with suffiicent energy in order to react

Question 2

Units of Concentration [ ]

Answer 2

mol per litre!

Question 3

Rate equation

Answer 3

Rate = change in amount / time

Question 4

Where is the max rate on a graph?

Answer 4

at the beginning usually

Question 5

How to find rate at instant

Answer 5

1. draw tangent to point
2. extrapolate line so that values can be read
3. use gradient equation (rise/run)

Question 6

Average rate of change steps

Answer 6

1. draw chord between two point

2. use gradient equation

Question 7

When does the rate of reaction equal zero?

Answer 7

When the reaction has gone to completion

Question 8

What factors influence the rate of a reaction?

Answer 8

1. Concentration [ ]
2. Temperature
3. Pressure (gaseous systems ONLY)
4. surface area (SA)
5. addition of a catalyst

Question 9

Which factors increase the frequency of collisions?

Answer 9

1. Temperature (inc in Kinetic energy -> inc collisions)
2. Concentration (inc collisions)
3. Pressure (inc [ ] -> inc collisions)
4. SA (inc [ ] -> inc collisions)

Question 10

What factors change the proportional of particles with sufficient activation energy?

Answer 10

1. Temperature (inc kinetic energy -> inc Ea)

2. Catalyst (orientates particles and dec Ea barrier)

Question 11

What are enzymes?

Answer 11

Biological catalysts which work only with organic material

proteins which are specific for reaction

Question 12

How do enzymes work?

Answer 12

Match the shape of the substance under going change
shape is determined by secondary bonding
conditions under which the enzyme will work must maintain the shape of the enzyme

Question 13

What temperatures will enzyme not work?

Answer 13

Temps greater than 50 degrees

only in narrow pH range

Question 14

How will activation energy (on energy profile) chnage with the addition of a catalyst?

Answer 14

Ea will be lower