Section 5- Soilds, Liquids and Gases P1 Flashcards
Define density:
Density is the ‘compactness’ of a substance.
What is the equation linking mass, density and volume?
Density (ρ) = mass ÷ volume
What unit is density measured in:
g/cm³ or kg/m³
How can density determine whether an object will float or sink?
A soli object will float on a fluid if it has a lower density than the fluid.
Describe a practical for how you can find the density of an object:
- use a mas balance to measure its mass
- if its a regular shape measure it with a ruler and work out its volume, if its irregular you can submerge it in water and measure the displacement in a measuring cylinder
- use the formula to find its density
How can you use a eureka can to find the volume of an irregular shaped object?
- Submerge the object in a eureka can full of water
- The water displaced by the object will be transferred to the measuring cylinder(under the eureka can’s spout)
- The volume of water in the measuring cylinder is the volume of the object
Define pressure:
Pressure is a measure of the force being applied to the surface of something.
What unit is pressure measured in:
pascals (Pa) or kilopascals (kPa)
What is the equation linking force, area and pressure?
Pressure = force(N) ÷ area(m²)
How is pressure affected in gases and liquids with depth?
The pressure increases with depth (it builds up as you go closer to the earth)
Define pressure difference:
Pressure difference is the difference in pressure between two points in a liquid or gas.
What is the equation linking height, gravitational field strength, pressure difference and density?
pressure difference =height x density x gravitational field strength
What is absolute zero?
Absolute zero is as cold as stuff can get
0 Kelvins (-273°C)
-at absolute zero particles have as little energy as they can possibly
How do you convert from degrees Celsius to kelvins?
add 273
How do you convert from kelvins to degrees Celsius?
subtract 273
What does particle theory state:
Gases consist of very small particles which are constantly moving in random directions.
-The particles take up hardly any space most of the gas is empty space
What is the relationship between the temperature of a gas and its particles?
The temperature of a gas(in kelvins) is proportional to the average energy in the kinetic energy stores of its particles.
-this means if you double the temperature, you double the average kinetic energy stores
What is the relationship between pressure and colliding gas particles?
When gas particles collide with something they exert a force and their momentum and direction changes. In a sealed container when this happens it creates an outward pressure.
What can alter the pressure inside of a sealed container?
How fast the particles are going and how often thy hit the walls
What is the relationship between temperature and pressure?
Temperature and pressure are proportional. (double the temperature for a fixed volume of gas, the pressure doubles as well)
Why is the relationship between temperature and pressure proportional?
If you heat a gas, the particles move faster and have more energy in their kinetic stores.
- the increase in energy means particle collisions are more frequent and harder
- this results in a larger force, creating more pressure
What is the relationship between pressure and volume?
if you put the same fixed amount of gas:
- in a bigger container, the pressure will decrease, because of fewer collisions
- in a smaller container, more collisions so bigger force so the pressure is increased
What is the equation linking pressure and volume?
pressure x volume = constant (pV = constant)
p₁V₁ = p₂V₂
What is the equation linking pressure and temperature?
pressure ÷ temperature(K) = constant (p ÷ T = constant)
p₁÷T₁ = p₂÷T₂
