Topic Test Flashcards
What are the properties of a solid?
- Arranged regularly and close together
- Only able to vibrate at fixed positions
- Strong forces of attraction which hold them together
What are the properties of a liquid?
- Particles are still mostly touching but have some gaps
- Less dense than solids
- Forces of attraction are less effective than solids
- Move around freely and arranged randomly
What are the properties of a gas?
- Move randomly at high speeds in every direction
- Particles are further apart
- Almost no forces of attraction
What is the temperature at which a solid melts at called?
The Melting Point
What is freezing?
The liquid is cooled, forcing the Particles to slow down until the forces of attraction hold them in positions and turn them into a solid. This is called freezing.
What is it called when a liquid forms a solid
The temperature at which a liquid become a solid is called the freezing point
Why does diffusion happen quicker in some gases compared to others?
Those gas particles may be lighter, allowing them to move faster and p, therefore, diffuse quicker.
What is diffusion?
Diffusion is the net movement of molecules from a high concentration to a low concentration, down the concentration gradient
What is boiling?
Boiling occurs when a liquid is heated so much that it loses its forces of attraction and changes state. The higher the boiling point, the more energy is required to overcome the forces of attraction
What is evaporation?
Some particles move quicker or slower than the normal particles. The faster particles will be able to overcome the forces of attraction and break free to form a gas.
What is the process called when a solid changes to a gas or vice versa?
Sublimation or Deposition
States at different melting and boiling points
If a substance is below its melting point, it is a solid. If it is in between it’s melting and boiling point, it is a liquid. If it is above it’s boiling point it is a gas.
What is diffusion in a liquid?
Without movement, diffusion in a liquid is very slow. This is because the particles in a liquid move slower than particles in a gas. The particles in a liquid are also closer together, so there is less space for the particles to move into without colliding with each other
A substance that dissolves is called a…
SOLUTE
The liquid that the solute dissolves in is called the…
Solvent
The liquid formed from a solute and a solvent in a…
Solution
The solubility is a solvent at a particular temperature is described as…
The mass of solute which must dissolve in 100g of solvent at that temperature to form a saturated solution
What is a saturated solution?
A solution containing as much dissolved solid as possible at a specific temperature
When something is released when it is cooling, we say…
The things crystallizes out of the solution or precipitates out of the solution
What is an element?
Elements are substances which only contain one type of atom
What is a compound?
A compound is two or more elements that are chemically joined together
What is a mixture?
A mixture is a substance with two or more elements and/or compounds that are not chemically joined together
What is simple distillation?
Simple distillation is when you separate a mixture of liquids by heating it and allowing it to evaporate and condense down a condenser.
What is fractional distillation?
Fractional distillation is used to separate a mixture of two or more liquids which on miscible with different boiling points. It takes advantage of the mixtures different boiling points and is like distillation, except it separates a mixture into parts called fractions.
What is filtration?
Filtration is used to separate an insoluble solid from a liquid. It can be used to separate 2 solids as well, but only if one is soluble in water.
How can Mixtures be separated?
Mixtures can be separated by physical means that don’t involve any chemical reactions like changing the temperature.
Pure substances
Pure substances melt and boil at fixed temperatures. For example, water melts at 0 Celsius and boils at 100 Celsius. On the other hand, mixtures boil over a range of temperatures. You can use the melting point to determine whether or not a substance is pure.
What is Crystallization?
It is used to separate a solute from a solvent
What is paper chromatography?
It is used to separate a variety of mixtures (typically inks or food colourings). It can be used to identify particular dyes in a mixture.
How do you describe a compound when talking about paper chromatography?
When comparing compounds in an ink in paper chromatography, if it asked you to describe a compound, you should check what it has in relation to the other compounds.
How do you calculate the rf value?
Rf=distance moved by the spot(from the pencil line) divided by the distance moved by the solvent front(from the pencil line). It must be between 0 and 1 or you have made a mistake
