5 Flashcards
Formula for density.
Density = mass/volume
Formula for pressure.
Pressure = force/area
Formula for pressure difference.
Pressure difference = height x density x gravitational field strength
Define pressure, and explain it in fluids.
Pressure is the concentration of a force.
When an object is submerged in a fluid(liquids or gases) pressure is exerted evenly across all of the objects surface.
Define Thermal Energy.
Sum of Kinetic energy and Potential energies in a substance.
Molecular Kinetic energy increases with temperature while Potential energy increases when an object changes state
Define and provide the formula for Specific Heat Capacity.(2)
The amount of energy required to raise the temperature of 1 kg of the substance by 1 °C. A substance with low SHC will heat up quickly and cool down quickly, and a substance with high SHC will heat up and cool down slowly.
Specific Heat Capacity = Change in Thermal Energy / mass x change in temperature
OR
Change in Thermal Energy = Mass x Specific Heat Capacity x Change in Temperature
Describe how arrangement and movement of particles in a solid, liquid and gas differ?(3)
In solids particles are closely packed together and vibrate around a fixed position. Definite shape and volume
In liquids particles are closely packed but can flow over one another. They do not have definite shape, but they do have a definite volume.
In gases particles are far apart, move randomly and will therefore often have large gaps between the particles. Gases do not have definite shape or volume.
Why will heating a system raise its temperature or produce changes of state?
Heating a system will increase the kinetic energy of the particles within it, this can cause the temperature to increase, or it to change state.
Explain Kinetic Theory and how an increase in temperature results to an increase in the average speed of gas molecules?(3)
Molecules in gas are in constant random motion at high speeds. This means they will undergo sudden changes when they collide with walls of a container or other particles. This random motion is known as Brownian motion.
As the gas particles randomly collide and hit the walls of the container, they produce a net force at right angles to the container.
Therefore a gas at higher temperature will have particles colliding more frequently against the walls of the container, and with a greater force because they will have more kinetic energy.
Define absolute zero.
Absolute zero is the point of -273 C or 0 Kelvin, and is defined as the temperature at which the molecules in a substance have zero kinetic energy.
How are pressure and volume related - also - pressure and kelvin related?(2)
Pressure is inversely proportional to volume; decrease in volume will increase pressure.
Pressure is directly proportional to kelvin; decrease in average kelvin will decrease pressure.
State Boyle’s law.
P1 x V1 = P2 x V2
P1 = initial pressure in pascals (Pa)
V1 = initial volume in metres cubed (m3)
P2 = final pressure in pascals (Pa)
V2 = final volume in metres cubed (m3)
State the Pressure Law.
P1/T1 = P2/T2
P1 = initial pressure (Pa)
P2 = final pressure (Pa)
T1 = initial temperature (K)
T2 = final temperature (K)
