Science Term 2 Flashcards
independent variable
a variable that isn’t changed by other variables
dependant variable
a variable that changes because of the independent variable and is measured
controlled variable
a variable that doesn’t change
distillation (how it works)
first, the liquid that has the lower boiling point in the solution is evaporated and the gas is trapped and forced into the condenser which is cooled to form the distillate which goes into the recieving flask
filtration (how it works)
you put a funnel into a beaker, then get the filter paper and fold it in half twice. Now put the filter paper into the funnel, which can go in a cronical flask and pour your solution in
what are all the stages of heating?
melting and boiling
what are the stages of cooling
condensation and freezing
how is chromatography used?
used to separate solutions with very small concentrations of coloured solutes.
what is paper chromatography
(how to do it)
A solute is dotted on the end of a piece of special chromatography paper. The very end of the paper is then dipped into a solution, and the solute then moves up the paper.
can chromatography work on colloids and suspensions?
No
what is a solvent
a substance that should easily dissolve the solute
what is a solute
a solute is a substance that is meant to be dissolved in the solvent
what does dilute mean?
to make a liquid weaker by adding a solvent, such as water
what does concentrated mean?
When there is more solute then the solvent
what is a heterogeneous mixture?
a heterogeneous mixture is where the solid particles are spread throughout the solution without dissolving in it
what is a colloid?
any substance consisting of particles substantially larger than atoms or ordinary molecules but too small to be visible to the unaided eye;
what is a homogeneous mixture?
a mixture in which the composition is not uniform throughout the mixture.
what does soluble mean?
A substance is dissolvable
what does insoluble mean?
A substance cannot be dissolved
in chromatography what does the dye that reaches the highest on the paper mean?
It is the most soluble
what is sedimentation?
When the solute that hasn’t been dissolved settles at the bottom of the mixture, but not because of gravity
What is the distillate
a substance collected after distillation
what is resedue
a mixture that is left behind
What is expansion?
when heat is added to particles which causes the space between the particles to increase
what is density and how do you find it?
the measurement of how many particles are in any given space. you can measure this by D= mass over volume
What is Centre fusion
when a substance is spun around and separated according to density. Least dense on top and most dense on the bottom
What is a suspension?
when particles that have not been dissolved in a mixture sink to the bottom of the container due to gravity
why do objects expand and contract when heated or cooled?
there is an increase/decrease in kinetic energy that causes the particles to vibrate/still and the bonds between them become weaker/stronger
