14.1 - 14.5 Flashcards
how do you convert from Kelvin to Celcius
take 273 from the kelvin value to get it in °C
why is ice less dense than water
the molecules freeze forming a regular crystalline pattern. the molecules are held slightly further apart than the irregular liquid arrangement so its less dense
define internal energy
the sum of the randomly distributed kinetic and potential energies of atoms/molecules within a substance
why does the temperature of a substance stay the same while it is changing state
the input energy transfers to the potential energy of the molecules. temperature measures average kinetic energy so it doesn’t increase
why do gases have the highest potential energy
the electrostatic force between molecules are negligible so its effectively 0J. in liquid and solids the potential energy is negative because energy needs to be supplied to break the bonds
define specific heat capacity
the energy per unit mass to increase the temperature of a substance by 1K
what decreases the accuracy in an experiment to find the specific heat capacity of a substance
lack of insulation
incomplete combustion
incorrect mass of the substance burned/heated
define ‘specific latent heat’
the energy required to change the phase of a substance per unit mass
what’s the latent heat from solid to liquid and liquid to gas
solid to liquid: specific latent heat of fusion
liquid to gas: specific latent heat of vaporisation
which latent heat is greater and why
the latent heat of vaporisation is greater because there is a larger difference in potential energy of gasses and liquids than for liquids and solids
