States Of Matter Flashcards
The three states of matter
Solid, liquid and gas
Characteristics of a solid (6)
The particles are arranged regularly
Packed closely together
Only able to vibrate about fixed positions
They can’t move around
The particles have strong forces of attraction between them which keeps them close together
Less kinetic energy than liquids and gases
Characteristics of a liquid (7)
The particles are still mostly touching
Some gaps appear which is why liquids are usually less dense than solids
The forces between the particles are less
The particles can move around each other
The particles are arranged randomly,
More kinetic energy than solids
Less kinetic energy than gases
Characteristics of a gas (4)
Particles are moving random
Y at high speed in all directions
The particles are much further apart
There is almost no forces of attraction between them
More kinetic energy than solids and liquids
What are the scientific steps when you heat a solid
When you heat a solid:
- The energy provided by the heat source makes the particles in the solid vibrate faster.
- Eventually, they vibrate so fast that the forces of attraction between the particles are not strong enough to hold them together.
- The particles are then able to move around each other.
- The solid melts to form a liquid.
- The particles in the liquid have more kinetic energy than the particles in a solid.
- So, energy has to be supplied to convert solid into a liquid
When does boiling occur?
Boiling occurs when:
- A liquid is heated so strongly that the particles are moving fast enough to overcome all the forces of attraction between them.
- The stronger the forces of attraction, the higher the boiling point of the liquid.
- This is because more energy is needed to overcome these forces of attraction.
What happens when the liquid is cooled?
If the liquid is cooled:
- If it is cooled again, the liquid particles will move around more slowly.
- Eventually, they are moving so slowly that the forces of attraction between them will hold them in a fixed position.
- And the particles pack more closely together into a solid.
- The liquid freezes forming a solid.
Melting point
The temperature at which the solid melts
Freezing point
The temperature at which the liquid freezes
What link is there between the melting point and the freezing point?
The temperature of the melting point and the freezing point of a substance is exactly the same.
What happens if a gas is cooled?
- The particles eventually move slowly enough that forces of attraction start to form and hold them together as a liquid.
- The gas condenses.
How do you get from a solid to a liquid?
Melting
Liquid to a solid
Boiling
Liquid to gas
Evaporating
Gas to liquid
Condensing
Solid to gas
Give a substance that does this?
Sublimation
Carbon dioxide
Gas to solid
Deposition
How is evaporation different to boiling?
Evaporation is different.
• In any liquid or gas, the average speed of the particles varies with the temperature.
• But at each temperature, some particles will be moving faster than the average.
• Some very fast particles at the surface of the liquid will have enough energy to overcome the forces of attraction between the particles.
• They will break way to form a gas. This is called evaporation.
• If the liquid is in a closed container, particles in the gas will also be colliding with particles at the surface of the liquid.
• If they are moving slowly enough, they will be held by the attractive forces and become part of the liquid.
• In a closed container, evaporation and condensation will be occurring at the same time.
Working out the physical state of a substance at a particular temperature.
Q: The temperature is 30 degrees. The melting point is 801 and the boiling point is 1413. What is the physical state?
Solid because the temperature has to be below the melting and boiling point
Working out the physical state of a substance at a particular temperature
Q: The temperature is 80 degrees. The melting point is 0 and the boiling point is 100. What is the physical state?
Liquid because the temperature has to be between the melting and boiling point
Working out the physical state of a substance at a particular temperature
The temperature is 30 degrees. The melting point is –259 and the boiling point is –253. What is the physical state?
Gas because the temperature had to be above the melting and boiling point
What is diffusion?
What does it happen in?
Diffusion is the spreading out of particles in a gas or a liquid.
Diffusion is particles moving from a higher concentration to a lower concentration until the concentration is even
Diffusion in gases
This experiment relies on the reaction between ammonia and hydrogen chloride gases to give white solid ammonium chloride
Steps, what would happen, conclusion
- Pieces of cotton wool are soaked in concentrated ammonia solution and concentrated hydrochloric acid.
- These are placed in the ends of a long glass tube with rubber bungs (to stop the poisonous gases to escape).
- Ammonia particles and hydrogen chloride particles diffuse along the tube.
- A white ring of solid ammonium chloride forms where they meet.
- The white ring takes time to form and appear closer to the hydrochloric acid end.
- Ammonia has moved further than the hydrochloric acid.
- This means that the ammonia particles are lighter than the hydrogen chloride particles and therefore move faster.
Diffusion in gases
Another experiment is a gas jar of bromine gas on the bottom and gas jar of air on top.
What happens and why doesn’t it happen instantly
The brown colour in the bottom jar spreads out when the lid is removed until there is an even colour in both jars.
This experiment shows a gas diffusing from high concentration to low concentration until it is even.
It doesn’t happen instantly as the bromine and air particles move randomly, constantly colliding with each other and changing direction
Diffusion in liquids
A small jar of purple solution is placed at the bottom of a big gas jar full of water.
What happens if the experiment is made at a higher temp?
What happens and what does this show?
takes several days for the purple colour to spread evenly.
This shows that diffusion in a liquid is lower than in a gas because the particles move more slowly and they have less space between them.
NOTE: IF THE EXPERIMENT IS MADE AT A HIGHER TEMP, IT WOULD TAKE LESS TIME TO MOVE BECAUSE THE PARTICLES HAVE MORE ENERGY AND NEEDS TO DIFFUSE MORE.
Demonstrating particles are tiny by dilution
When a dark purple solution Is diluted with lots of water, the purple colour can still be seen in even just 1 drop of the diluted solution. To see the purple colour, you still need a huge number of particles so the particles must be very tiny
Solute
The substance for example the solid which dissolves
Solvent
A liquid that the solute dissolves in
Solution
A mixture made by dissolving a solute in a solution
Saturated solution
A solution which contains as much dissolved solute as possible at a particular temperature
Solubility and units
Solubility of a solid is measured in g per 100g of solvent and refers to the maximum mass of solid that can dissolve in a solvent at a given temperature.
UNITS ARE G/100g or G/100cm〖^3〗 water.
Practical - to find the solubility of a solid at a particular temperature
This one is 40 degrees
- Measure out 100cm〖^3〗 of water.
- Heat the water to above 40 degrees
- Add solid until no more can dissolve.
- Cool solution to exactly 40 degrees.
- Then quickly filter into a weighed evaporating basin (which is called A).
- Reweigh it (which is called B).
- Then evaporate off the water and reweight it (called C).
- Determine the mass of solid (C-A).
- Determine the mass of water evaporated (B-C).
- Find out solubility using the equation.
Equation to work out solubility
Mass of solid / mass of water x 100
Look at OneNote for
Plotting and interpreting solubility curves
