p6: energy of matter

Question 1

which 2 quantities do you need to measure to find the density of a solid or liquid

Answer 1

mass
volume

Question 2

what happens to the particles in a substance if its temperature is increased

Answer 2

they move faster and the energy in their kinetic energy store increases

Question 3

why is the mass of a substance conserved when it changes state

Answer 3

the number of particles does not change

Question 4

why are changes of state physical changes

Answer 4

no new substances are produced and the substance will have the same propertie4s as before if the change is reversed

Question 5

what is the internal energy of a substance

Answer 5

the total kinetic energy and potential energy of all the particles in the substance

Question 6

why does a graph showing the change in temperature as a substance cools have a flat section when the substance is changing state

Answer 6

the energy transferred during a change in state causes a change in the internal energy of the substances

Question 7

what is the name given to the energy transferred when a substance changes state

Answer 7

latent heat

Question 8

what is the specific latent heat of a substance

Answer 8

the energy required to change the state of one kilogram of that substance with no change in temperature

Question 9

what is the specific latent heat of fusion a substance

Answer 9

the energy required to change one kilogram of the substance from solid to liquid at its melting point without changing its temperature

Question 10

what is the specific latent heat of vaporization of a substance

Answer 10

the energy required to change one kilogram of the substance from liquid to vapor at its boiling point without changing its temperature

Question 11

on a graph of temperature against time for a substance being heated up or cooled down what do flat sections show

Answer 11

the time when the substance is changing state and the temperature is not changing

Question 12

what property of a gas is related to the average kinetic energy of its particles

Answer 12

temperature

Question 13

what causes the pressure of a gas on a surface

Answer 13

the force of the gas particles hitting the surface

Question 14

give 2 reasons why the pressure of a gas in a sealed container increases if its temperature is increased

Answer 14

the molecules moves faster so they hit the surfaces with more force
the number of impacts per second increases