P1: Matter

P1.1 The particle model

P1.1a describe how and why the atomic model has changed over time

P1.1b describe the atom as a positively charged nucleus surrounded by negatively charged electrons, with the nuclear radius much smaller than that of the atom and with almost all of the mass in the nucleus

P1.1c recall the typical size (order of magnitude) of atoms and small  molecules

P1.1d define density

P1.1e explain the differences in density between the different states of matter in terms of the arrangements of the atoms and molecules

P1.1f apply the relationship between density, mass and volume to changes where mass is conserved (M1a, M1b, M1c, M3c)

P1.2 Changes of state

PM1.2i apply: change in thermal energy (J) = mass (kg) x specific heat capacity (J/kg°C) x change in temperature (°C)

PM1.2ii apply: thermal energy for a change in state (J) = mass (kg) x specific latent heat (J/kg)

P1.2a describe how mass is conserved when substances melt, freeze, evaporate, condense or sublimate

P1.2b describe that these physical changes differ from chemical changes because the material recovers its original properties if the change is reversed

P1.2c describe how heating a system will change the energy stored within the system and raise its temperature or produce changes of state

P1.2d define the term specific heat capacity and distinguish between it and the term specific latent heat

P1.2e apply the relationship between change in internal energy of a material and its mass, specific heat capacity and temperature change to calculate the energy change involved (M1a, M3c, M3d)

P1.2f apply the relationship between specific latent heat and mass to calculate the energy change involved in a change of state (M1a, M3c, M3d)

P1.3 Pressure

PM1.3i apply: for gases: pressure (Pa) x volume (m3) = constant (for a given mass of gas and at a constant temperature)

PM1.3ii apply: pressure due to a column of liquid (Pa) = height of column (m) x density of liquid (kg/m3) x g (N/kg)

P1.3a explain how the motion of the molecules in a gas is related both to its temperature and its pressure

P1.3b explain the relationship between the temperature of a gas and its pressure at volume (qualitative only)

P1.3c recall that gases can be compressed or expanded by pressure changes and that the pressure produces a net force at right angles to any surface

P1.3d explain how increasing the volume in which a gas is contained, at constant temperature can lead to a decrease in pressure

P1.3e explain how doing work on a gas can increase its temperature

P1.3f describe a simple model of the Earth’s atmosphere and of atmospheric pressure

P1.3g explain why atmospheric pressure varies with height above the surface of the planet

P1.3h describe the factors which influence floating and sinking

P1.3i explain why pressure in a liquid varies with depth and density and how this leads to an upwards force on a partially submerged object

P1.3j calculate the differences in pressure at different depths in a liquid (M1c, M3c)