module 3 Flashcards
What are the equations for density?
M=P*V M=mass (kg) P=density (kg/m cubed)V=volume(m cubed)
What is density?
Measure of compactness, density of object depends what it’s made of and how its particles are arranged. Dense material=tightly packed particles.
How do forces of attraction act on particles?
Solid:strong, liquids:weaker, gas:almost no forces.
How do you measure the density of a solid object?
measure mass of object, if possible measure length,width and height, then calculate formula. If can’t measure solid use eureka can. Put it in can with water. Some water will leave can to go to measuring cylinder, record water in measuring cylinder=volume. use formula to find density.
How do you find the density of liquids?
put 10 ml of liquid in measuring cylinder and record mass place another 10 ml until cylinder is full record volume and mass find density. Find average=total density.
What forces are acting on particles when moving in a system?
Kinetic energy store for movement, potential energy store due to positioning, energy stored in system is in particles. heating system transfers energy to particles (kinetic) increasing internal energy. Leads to temperature or state change. Temperature:size of change depends on mass of substance and what is made from and energy input. State:heated enough-particles have enough energy in kinetic stores to break bonds.
What is sublimation?
Change from solid to gas
How does a new state form?
Physical change, no new substance only in different form, can reverse to make it have original properties particle numbers don’t change same mass.
Why does a state change require energy?
you put energy into a substance to change its state by increasing its internal energy, energy used for breaking intermolecular bonds rather than raising temperature, there are spots where energy is being used for temperature change.
Why does a state change of decreasing temperature require energy?
When a substance condenses or freezes bonds form between particles which releases energy, internal energy decreases but temperature doesn’t fall until liquid or solid energy needed to transfer substance=latent heat
Why is specific heat capacity needed to change state of a substance of 1 kg?
specific latent heat of substance is amount of energy needed to change 1 kg from 1 state to another without changing temperature-cooling specific latent heat is released by change of state, specif latent heat different for each material and changing between states.
how is specific latent heat is needed for state change?
state change of solid called specific latent heat of fusion. for gas and liquid is called specific latent heat of vaporisation.
What is the equation for energy needed for a state change?
Energy(E[j])=mass(m[kg])*specific latent heat(L[j/kg])
How do particles in gas move?
random directions and speeds, increasing temperature transfers energy to kinetic energy store of particles. temperature related to average energy in kinetic energy stores of particles in gas. Higher temperature=higher average energy. increase in energy=increase in speed due to more energy in kinetic energy stores.
What happens when gas particles collide?
they exert force, in sealed container outward gas pressure is total force exerted by all particles on unit of walls. faster particles=more collisions and increase in net force and pressure increase temperature=increase speed and pressure (if constant volume).
