AQA A LEVEL PHYSICS PAPER 2 QUESTIONS
AND ANSWERS.
what is meant by specific heat capacity ANS -the energy needed to raise the temperature of 1kg of
material by 1C.
define avogadro's constant ANS -the number of atoms in 12g of carbon 12 (OR the no. of
particles/atoms in one mole of a substance)
define the specific latent heat of vaporisation of water ANS -the energy required to change the state of
a unit mass of water to gas (1) without a change in temperature (1)
features of an ideal gas (3) ANS -- collisions are elastic
- molecules have negligible volume
- gas obeys ideal gas law (Boyles law)
assumptions made in the molecular kinetic theory of an ideal gas ANS -- all molecules are identical
- molecules in random motion
- newtonian mechanics apply
- vol of gas molecules negligible (compared to vol of gas)
- collisions are elastic
state and explain what happens to the speed of molecules in a gas when the temperature increases
ANS -the average/mean speed of molecules increases (1) as mean ke proportional to absolute temp
state what is meant by an elastic collision ANS -a collision in which ke is conserved
two different gases at the same temp have molecules with different mean square speeds. explain how
this is possible ANS -masses are different (1) but because ke same, mean square speeds must be
different
AND ANSWERS.
what is meant by specific heat capacity ANS -the energy needed to raise the temperature of 1kg of
material by 1C.
define avogadro's constant ANS -the number of atoms in 12g of carbon 12 (OR the no. of
particles/atoms in one mole of a substance)
define the specific latent heat of vaporisation of water ANS -the energy required to change the state of
a unit mass of water to gas (1) without a change in temperature (1)
features of an ideal gas (3) ANS -- collisions are elastic
- molecules have negligible volume
- gas obeys ideal gas law (Boyles law)
assumptions made in the molecular kinetic theory of an ideal gas ANS -- all molecules are identical
- molecules in random motion
- newtonian mechanics apply
- vol of gas molecules negligible (compared to vol of gas)
- collisions are elastic
state and explain what happens to the speed of molecules in a gas when the temperature increases
ANS -the average/mean speed of molecules increases (1) as mean ke proportional to absolute temp
state what is meant by an elastic collision ANS -a collision in which ke is conserved
two different gases at the same temp have molecules with different mean square speeds. explain how
this is possible ANS -masses are different (1) but because ke same, mean square speeds must be
different
