P6 Molecules And Matter Flashcards
What is definition of melting point
Temperature at which a substances changes from a solid to a liquid
What is definition of boiling point
Temperature at which a substance changes from a liquid to a gas
What is internal energy
The sum of the kinetic and potential energy of the system
What is specific latent heat
The amount of energy needed to change the state of 1kg of a substance
What is difference between specific latent heat of fusion and vaporisation
Fusion is solid to liquid
Vaporisation is liquid to gas
Wha is the unit of specific latent heat
J/Kg
What is density
Measure of the ‘compactness’ of a substance. Relates the mass of a substance to how much space is takes up
What is the formula for density
P=m/v
Density(kg/m3)= mass(kg)/volume(m3)
How do you find the density of an irregular object
Fill eureka can with water and let water flow out from spout. Now the water is just below the spout so anything placed into the eueka can, can be measured with water displaced. Place an empty measuring cylinder below end of the spout. Place object in water and messure how much water displaced. Subsitute the objects mass in the density formula.
What is internal energy
The total energy that its particles have in their kinetic and potential energy stores
What is it called when a gas turns to a liquid
Condensing
What is it called when a liquid turns to a solid
Freezing
What is it called when a liquid turns to a gas
Boiling/evaporating
What is it called when a solid turns to a liquid
Melting
What is it called when a solid turns to a gas
Sublimating
What is a change of state
Physical change of a substance meaning you dont end up with a new substance but its just the firm of the substance that changes
What do the flat lines show in a heating graph
Shows energy is beung used to break bonds to change its state
What is latent heat
Amount of energy needed to change the state of a substance
What is specific latent heat
The amount of energy needed to change 1kg of a substance from one state to another without changing its temperature
What is specific latent heat of fusion
SLH for changing between a solid and a liquid
What is SLH for vaporisation
SLH for changing between a liquid and a gas
What is the equation to find out energy needed to change a state
E=mxL
Energy for a change in state (j) = mass(kg) x specific latent heat (j/kg)
What is the relationship between volume and pressure
pV=constant
Pressure and volume = constant
How can you increase pressure of a gas
Increase in temperature
What does in increase in volume of gas do to its pressure
Decreases in pressure
What is the equation for density and give units?
Density (Kg/m^3) = mass (Kg) / volume (m^3)
How are the particles arranged in a dense material?
Closely packed together
How do you find the density of a regular object?
Measure its mass using a weighing scale, measure the length, width, and height of the object to find its volume. Substitute the volume and mass into the density equation.
How do you find the density of an irregular object?
Weigh the object with a weighing scale. Fill a Eureka can with water up to the spout. Place a measuring cylinder underneath the exit of the spout and place the object in the Eureka can. The volume of water displaced is the volume of the object.
How do you find the density of a liquid?
Put a measuring cylinder on a weighing scale and tare it to 0. Pour 10ml of the liquid into the measuring cylinder and record the weight shown. Substitute the mass and volume in the density formula.
What is the internal energy of a system?
The total energy that its particles have in their kinetic and potential energy store.
What does heating a system do to the internal energy?
They gain energy in their kinetic energy which increases the internal energy.
Explain the arrangement and energy of the particles in a solid.
Strong forces of attraction hold the particles together in a fixed and regular arrangement. The particles don’t have much energy, so only vibrate about their fixed position.
Explain the arrangement and energy of the particles in a liquid.
Moderate forces of attraction between particles. The particles are close together but can move past each other, forming irregular arrangements. They have more energy than particles in a solid.
Explain the arrangement and energy of the particles in a gas.
Almost no forces of attraction between the particles. Particles have more energy than in liquids and solids. They are free to move and are moving in random directions at high speeds.
What is pressure?
The force exerted per unit area.
Explain how colliding gas particles create pressure.
Particles in gases are free to move around. As they move, they bang into each other and whatever else gets in the way. When they collide with something, they exert a force, and pressure is the amount of force exerted.
How does increasing the temperature of a gas increase its pressure?
If you increase the temperature of the gas, you transfer energy to the kinetic energy stores of its particles. Therefore, the speed at which the particles vibrate increases, which will increase the force exerted.
What does density measure?
The compactness of a substance.
