Heating/ Cooling Curves

Question 1

heating- what happens in solid?

Answer 1

substance heated, particles gain additional energy as kinetic energy and temperature increases as particles start to move more. (vibrate around fixed point)

Question 2

heating- what happens in solid-liquid?

Answer 2

this is melting point substance heated and particles will gain enough kinetic energy to overcome inter-molecular forces between particles to undergo phase change. at this point particles will gain potential energy while kinetic energy and temperature will remain constant. (vibrations increase and the particles break from the fixed positions)

Question 3

heating- what happens in liquid?

Answer 3

particles gain kinetic energy and temperature rises

Question 4

heating- what happens in liquid-gas?

Answer 4

this is boiling point. particles gain potential energy while kinetic energy and temperature remains constant. (particles attractive forces weaken and break free of one another and the liquid turns to gas)

Question 5

heating- what happens in gas?

Answer 5

particles gain kinetic energy and temperature rises again

Question 6

cooling- what happens in gas?

Answer 6

particles lose kinetic energy and temperature falls (PARTICLES START MOVING LESS)

Question 7

cooling- what happens in liquid-gas?

Answer 7

Condensation occurs as particles lose potential energy and kinetic energy and temperature remains constant. (particles move less and attractive forces become more prominent)

Question 8

cooling- what happens in liquid?

Answer 8

As temperature decreases, particles lose kinetic energy and potential energy remains constant. ( particles move less and are becoming more ‘organised’)

Question 9

cooling- what happens in solid-liquid?

Answer 9

freezing occurs as Particles lose potential energy as kinetic energy and temperature remains constant. (particles movement decreases to vibrations as they move into more fixed positions

Question 10

cooling- what happens in solid?

Answer 10

particles lose kinetic energy and temperature decreases as potential energy remains constant. (particles in fixed positions and vibrate around fixed pint)

Question 11

what can melting points determine?

Answer 11

purity of substance

Question 12

wha if substance is impure?

Answer 12

melting point will be over a range of temperatures as individual constituents of a mixture retain their physical and chemical properties.

Question 13

what is fractional distillation?

Answer 13

separating crude oil into its components

Question 14

define temperature?

Answer 14

measure of kinetic energy of a substance

Question 15

define heat?

Answer 15

amount of energy transferred from one body to another spontaneously due to their temperature difference

Question 16

3 things that occur during change of state?

Answer 16

1. kinetic energy remains constant and therefore temp. is constant
2. Change in arrangement of particles
3. Potential energy increases or decreases