Separating Mixtures Flashcards
Define soluble, insoluble, and saturated
Soluble: describes that a substance can dissolve in a specific solvent
Insoluble: describes a substance that cannot dissolve in a particular solvent
Saturated: describes the state in which a solvent cannot dissolve any more of a solute at a specific temperature
Define solvent, solute, and solution
Solute: the substance that can dissolve (usually a solid)
Solvent: the liquid that the solute dissolves in
Solution: the mixture of a dissolved solute and solvent
Explain filtration
- Used when separating insoluble solids from a liquid
1) Pour the solution into a filter funnel
2) The liquid is able to go through the tiny holes in the filtration paper and goes through the filter funnel and into the conical flask
3) You are now left with the filtrate in the flask and the residue in the funnel
Explain decantation
- Separation technique effective on liquids with different densities or when an insoluble solid is present in a liquid
1) Pour the substance into the separatory funnel. The denser substance should always be at the bottom.
2) Open the stop cork to allow the substance at the bottom to flow through.
3) Close the stop cork as soon as all of the denser substance has been drained out of the separatory funnel into the conical flask.
Explain distillation
- Used when separating liquids and gases using their boiling points
- From liquid to gas, increase the heat
- From gas to liqud, decrease the heat
1) Heat the solution in the distillation flask to the appropriate temperature
2) The desired substance evaporates and as the vapour goes through the condenser, the constantly flowing cold water condenses the vapour
3) The liqudi in its purest form ends up in the beaker
Explain fractional distillation
- Used for the same purposes as distillation but when the substances’ boiling points are close to one another
1) Mixture is boiled
2) The substance goes through the fractionating tower
3) As the vapour reaches each tray within the tower, a specific substance condenses as the condensation point is right for that specific substance
Explain chromatography
- Used to separate the components of a solute (e.g., dye)
1) Fill the beaker with the solvent.
2) Hang the chromatography paper with mixture implemented on the base line (made of pencil)
3) Let the solvent travel to the through the chromatography paper
4) The solvent will carry the mixture and dissolve them. Each component has a specific Rf value in that solvent and will therefore travel a certain distance, separating the mixture.
Define element, compound, and mixture
Element: a pure substance that is made up of a single type of atom have the same number of protons in their nucleus
Compound: consists of molecules that are identical to one another and are made up of two or more chemically-bonded elements
Mixture: the physical combination a group of two or more substances without any chemical bonding
Explain the basic structure of an atom
Nucleus:
- Made up of protons and neutrons
- Has a tiny volume yet huge mass compared to the rest of the nucleus
Protons:
- Has a relative mass of 1 amu (atomic mass unit)
- Has a relative charge of +1, therefore it is positively charged
- Atoms of the same element have the same number of protons
- Number of protons are shown on the periodic table as the atomic number
Neutrons:
- Has a relative mass of 1 amu
- Has a relative charge of 0, so it is neutrally charged
- Number of neutrons varies in atoms of the same element and determines what isotope that atoms is
Electrons:
- Atomic mass of electrons is extremely small in comparison to protons and neutrons, practically 0
- Number of electrons = number of protons
- The number of electrons being greater or less than the number of protons will create a charged atom called an ion
- Ions with more electrons than protons will create a negative charge but less electrons than protons will create a positive charge
Energy level/shell:
Energy levels are fixed distances from the nucleus where electrons can be found
Explain crystalisation
- Used on solutions where the solvent’s boiling point is lower than the solute’s
1) Heat the solution in the evaporating basin at the right temperature
2) The solvent evaporates
3) You are now left with the solute
4) Let it cool down, allowing it to form crystals
Define stationary and mobile phase
Stationary phase: when mixture is staying still and is more attracted to the paper
Mobile phase: when mixture is moving and is attracted to the solvent and moving along it
How to calculate Rf value?
distance travelled by solute/distance travelled by solvent (solvent front)
How to calculate average relative atomic mass?
((abundance of A x mass of A) + (abundance of B x mass of B))/100
