principles of chemistry Flashcards
what are the properties of solids
fixed shape and volume
cannot be compressed
what are the properties of liquids
no fixed shape, but take the shape of their container
fixed volume
can flow
cannot be compressed
what are the properties of gas
no fixed shape, but take the shape of their container
do not have a fixed volume, but take up the volume of their container
can flow
can be compressed
properties of solids in terms of particles
have a regular arrangement
are tightly packed, particles are touching each other
vibrate about their position
have strong forces of attraction holding them in position
properties of liquids in terms of particles
have no regular arrangement
are tightly packed, particles are touching each other
move randomly at different speeds
do not move far as they frequently collide with other particles
have weaker forces of attraction compared to solids
properties of gas in terms of particles
have no regular arrangement
move randomly at different speeds, but much faster than liquids
have very weak forces of attraction compared to solids
what is melting
Applying thermal energy to a solid substance will result in it eventually becoming a liquid
what is evaporation
when liquid turns into gas
what is boiling
The process of applying thermal energy to a liquid to obtain a gas is called
what is condensation
turning gas into liquid, by cooling a gas
what is freezing
turning liquid into solid by further cooling the liquid
what is sublimation
from solid to gas
state change in state in terms of kinetic theory
the kinetic energy of the particles determines which state of matter a substance exists in. As the temperature of a substance increases, the average kinetic energy of the particles is increased and this can affect the physical state and properties of the material.
relationship between temp and gas state
As heat is added to the gas, the temperature of the gas increases. This makes each particle move faster and further, but still in random directions. It increases the distance between the particles, so the volume the gas occupies increases as the temperature increases.
relationship between pressure and gas state
In a gas, the particles exert a pressure on the walls (or sides) of any container in which they are held
When you increase the pressure of a gas at a fixed temperature, the volume of the gas decreases
describe and explain diffusion
diffusion is the movement of the particles from the area of high concentration to the area of lower concentration. We describe this as moving down the concentration gradient
describe and explain dependence of rate of diffusion on molecular mass
The greater the mass of the molecules, the slower the molecules move at any given temperature. At any given temperature, all substances have the same average kinetic energy. Therefore, lighter molecules need to have a greater velocity than heavier molecules.
describe difference between elements mixtures and compounds
element- made of only one type of atom, cannot be further broken down
compound-elements within cannot be further seperated, made when two or more elements chemically bond in a reaction
mixtures-made when elements or compounds are mixed with each other, substances within are not chemically bonded together, can be easily seperated
describe properties of metals
good conducters of electricity and heat, usually high melting point, malleable, ductile
describe properties of non-metals
bad conducters of electricity and heat, usually low melting point, not malleable,brittle
what is used to measure time
stopwatch
what is used to measure temp
thermometer
what is used to measure mass
mass balance
what is used to measure volume
burettes, volumetric pipettes, measuring cylinders and gas syringes
what are the methods of purification
with a solvent, filtration, crystsllisation, distillation
explain method of purification with a solvent
to separate two solids this method can be used, firstly add the solvent to the mixture, one solid must be soluble and the other not, then remove the not soluble solid from solvent, and evaporate solvent from remaining solid.
explain method of purification via filtration
used to separate an insoluble solid from a liquid, requires a filter funnel, the solid isnt able to pass through holes in filter paper, and is none as the residue, the liquid that can pass through is known as the filtrate
explain method of purification via crystallisation
to separate a soluble solid from a liquid, which have a different solubility. As temp of solution decreases less space available for solid in liquid, particles pushed out and gradually become crystals
explain method of purification distillation
separation of two liquids. through temporarily transforming them into gases.
first solution is heated in a distillation flask, then liquid with lowest boiling point evaporates and becomes a gas, it passes along the condenser in which cold water is passing through, which cools gas back into a liquid, which is collected in a beaker
explain method of purification fractional distillation
used to separate multiple liquids with different boiling points approximatly 25 c proximity. Apparatus same as simple distillation but has a frwctionating column, which has beads to provide a cool surface in which the vapour of liquid with highest boiling point go through and will condense and drop back into flask.
what is a solvent
a substance that dissolves a solute eg water
what is a solute
a substance that is dissolved in a solvent eg sugar
what is a solution
a mixture of one or more solutes dissolved in a solvent
what is a saturated solution
a solution containing max concentration of a solute dissolved in the solvent at a specific temperature
what is a residue
substance that remains after evaporation, distillation, filtration or any similiar process
what is a filtrate
a liquid or solution that has passed through a filter
what is the boiling and freezing point of water
100 degrees and 0
in chromotography how do you know substance is pure
only one spot/ colour is seen after process is done
in chromotography how can you tell a bit of the solute composition
if you also tested other substances, and the seperation has the same distance travelled in one spot, they contain the same solute
how is chromotography used to separate mixtures of soluble coloured substances
the unknown substances (solutes) are carried up a sheet of filter paper by the solvent, solutes move at different rate according to their mass and solubility, therefore they are deposited at differnet places in filter paper, being able to distinguish the solutes that compose the solution. A locating agent may also be used, which is a chemical substance that reacts with the seperated solutes to produce a coloured substance, clearly visible to calculate the rf value
what is rf value
distance travelled by the solute/ distance travelled by the solvent
