Section 23: Matter Flashcards
What is density
Density is a measure of the compactness of a substance, it relates the mass of a substance to how much space it takes up.
Equation for density
Density= mass/volume
How to find the density of a solid and liquid
- Use a measuring cylinder
- Use a mass balance to measure the mass of the empty measuring cylinder.
- Pour any liquid you investigating measure the mass of a cylinder again – the difference in mass is equal to the mass of a liquid.
- Find the volume from the cylinder scale.
How to find the volume of a prism
Find the area of its base then multiply it by height
How to find the volume of a cube
Length X width X height
How to find the volume of an irregular shape
You can find us volume using the fact that an object emerged in water will displace a volume of water equal to in volume
How to use a density bottle
- Measure the mass of the object using a mass balance.
- Fill the bottle with a liquid of a known density.
- Place to stop her into the bottle and dry outside.
- Measure the mass of the bottle.
- Into the bottom and place the object into the density bottle, repeat steps, two and three, then measure the mass of the bottle.
- Calculate the volume of displaced water.
Calculate the density of the object using the equation of density, with a mass measured in step one, and the volume you calculated to step six
How to calculate the volume of displaced water
The mass of displaced water equals mass2 - (m3-m1)
Then use the density of the water so you can use V=m/p to find the volume displaced.
What are the particles like in a solid?
- Strong forces of attraction hold the particles close together in a fix regular arrangement.
- The particles don’t have a much energy in the kinetic energy stores, they can only vibrate about in their fixed positions.
What are the particles like in a liquid?
The force of attraction between particles are weaker.
The particles are close together but can move past each other and form an irregular arrangement.
They don’t have as much energy in the kinetic stores than the particles in a solid as they move in random directions at low speed.
What are the particles like in a gas?
There are almost no forces of attraction between particles
particles have more energy in the kinetic energy stores than those in liquids
free to move as a travel in random directions a high-speed
What is a thermal energy store?
The energy in a substances thermal energy store is held by its particles in the kinetic energy stores
What happens when a substance is boiling
When you heat a liquid The extra energy is transferred into the particles kinetic energy store, making a move faster. Eventually, enough of the particles have enough energy to overcome the attraction to each other big bubbles of gas form in the liquid.
What happens when a substance is melting
The extra energy is transferred into particles, kinetic energy store, making a move faster. The extra energy makes the particles vibrate faster until eventually the forces between are partly overcome in the particle start to move around.
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 kg of a substance by 1°C
What is thermal energy?
The total energy stored by particles making up a substance or a system
What is temperature?
The average internal energy of a substance
What is the equation of specific heat capacity?
Change in thermal energy = m X c X change in temperature
How to find the specific heat capacity of water
- Use a mass balance to measure the mass of the insulating container
- Measure the container with water and measure the mass again. The difference in mass is the mass of the water in the container.
- There is the temperature of the water, then turn off the power of the power supply.
- Keep an eye on the thermometer when the temperature has increased, stop the experiment and record the energy on the joulemeter and the increase in temperature.
- You can I calculate a specific heat capacity of the water by rearrange the equation of the specific heat capacity.
- Repeat the whole experiment at least three times and calculate an average of the specific heat capacity.
What can you use instead of a Joule meter
You can also use a voltmeter and ammeter by timing how long the heater was on for then calculate the energy supplied
What is the energy useful when a substance is melting or boiling?
What substance is melting or boiling you’re still putting in energy the energy is used for breaking bonds between particles
Why doesn’t the temperature change when a substance is changing state
- When a substance is melting or boiling, you’re still putting an energy change. The energy is used for breaking bonds between particles rather than changing temperatures.
- What is substance is condensing of freezing bonds are forming between particles which releases energy. this means the temperature does not go down until the substance has turned into a liquid or a solid
How to workout the temperature changing in each state
- Fill a beaker with crushed ice
- Place at thermometer into the beaker and record the temperature of the ice.
- Using a Bunsen burner, gradually heat the beaker, full of ice
- Every 20 seconds record the temperature in the current state of the ice.
- Continue this process under the water begins to boil.
- Plot a graph of the temperature against time for your experiment.
What is specific latent heat
The
The amount of energy needed to change 1 kg of a substance from one state to another without changing its temperature
What is specific latent heat when cooling?
The energy is released by a change in state
What is specific latent heat of fusion?
The specific latent heat for changing between a solid and a liquid (melting/freezing)
What is specific latent heat of vaporisation?
The specific latent heat for changing between a liquid and gas (evaporating/boiling/condensing)
Specific latent heat equation
Thermal energy = mass X specific latent heat
How does gas create pressure?
Particles of gases collide with the walls of the container. even the gas particles are very small, they still have a mass so each collision exerts a force on the container. Gas pressure is caused by the collisions of the particles against the walls of the container. all these conditions cause a net force acting out words on the inside surface of the container. The force acting per unit area of the pressure.
What happens when there’s more gas particles in a container?
The more particles that are in a given volume down more often they will collide with the walls of the container and with each other, so the higher pressure there will be
What happens to the pressure when you increase the temperature
Increasing the temperature increase the pressure as the energy is transferred to the kinetic energy stores of the gas particles Meaning it moves faster
This is because the pressure a gas exerts container depends on how fast the particles are going and how often they hit the walls,
so if the temperature is increasing and the particles have more energy fast moving faster the particles were hit the container harder and more often creating more pressure.
What happens to the pressure if the temperature decreases
If the gas is cooled, the particles have less energy going to the kinetic energy stores, meaning they move less quickly, the particles hit the walls with less force and less often so the pressure is reduced
What is the maximum temperature a substance can get?
Absolute zero
What is absolute zero
-273°C
What happens at absolute zero
As little energy in the kinetic energy stores as it’s possible to get.
How to convert degrees Celsius into kelvin and the opposite
°C to K = +273
K to °C = -273
What happens if you apply force to an object
You may stretch, compress or bend
What do you need in order to stretch, compress opened an object.
You need more than one force acting on the object Otherwise the object was simply move in the direction of the applied. Force insert change shape.
Elastically distorted
An object has been elastically distorted if I can go back to the original shape and length after the force has been removed.
Objects that can be elastically distorted are known as an elastic object, for example a spring
Elastically distorted
An object has been elastically distorted if it doesn’t return to its original shape and length if the force has been removed
What is the elastic limit?
Where an object stops distorting elastically, and begins to distort inelastically
When is work done on an object
Work is done, when a force stretches or compresses an object and causes the energy be transferred to the elastic potential energy store of the object. If it is elastically distorted, all of this energy is transferred to the objects, elastic potential energy store.
How is extension directly proportional to the force?
The extension of a stretch spring or other elastic object is directly proportional to load all the force applied.
This means that there is a linear relationship between force and extension
What is the equation of a directly proportional extension?
F = K X x
What is a spring constant depended on?
Is dependent on the material that you are stretching, a stiffer spring has a greater spring constant
Equation of a inverse proportional extension
E = 1/2 X k X x^2
