Unit 12 - Experimental techniques and chemical analysis Flashcards
Common variables in chemistry
- Time
- Temperature
- Mass
- Volume
Units of time
- Seconds (s)
- Minutes (min)
- Hours (h)
- Days (d)
Units of temperature
- Celsius (˚C)
- Kelvin (˚K)
Units of mass
- Kilogram (kg)
- Gram (g)
- Tonne (t)
Units of volume
- Cubic meters (m^3)
- Cubic decimeters (dm^3)
- Cubic centimetres (cm^3)
Apparatus to measure time
- Stopwatch
Apparatus to measure temperature
- Thermometer
Apparatus to measure mass
- Mass balance
Apparatus to measure volume
- Burettes
- Volumetric pipettes
- Measuring cylinders
- Gas syringes
Measuring cylinder
- Used for volume of liquids
- Units of measurements are usually in cm^3
- Increments are usually in every 0.2 or 0.1cm^3
- Not very accurate for small values
Volumetric pipette
- Used for volume of liquids
- Transfers small volumes of liquids from one vessel to another
- Accurate for smaller volumes
Burette
- Used for volume of liquids
- Long tube that usually stores up to 50cm^3
- Very accurate
- Increments of 0.1cm^3
Gas syringes
- Used for volume of gases
- Inner chamber with a ground glass surface around a ground glass surface
- Gas-tight seal
- Can hold between 500cm^3 - 0.25cm^ and be accurate up to 0.01cm^3 depending on size
Solvent
Usually a liquid which dissolves a solute
Solute
The substance being dissolved by the solvent
Suspension
Mixture of substances, usually a liquid or solution with an insoluble solid due to separation of solid substances through solvents
Residue
The insoluble portion of the mixture/suspension
Filtrate
The soluble portion of the mixture/suspension
Solubility of a solid
Dependent on the temperature of the solvent
Saturated solution
A solution which contains as much of the solute as possible at a particular temperature of the solvent
Titration use
Finds out how much acid or alkali reacts with a certain volume of acid or alkali
Indicators
A substance that changes color depending if it is in the pretense of an acid or base
Common indicators in chemistry
- Litmus
- Thymolphthalein - Blue - colorless
- Methyl orange
- Phenolphthalein - colorless - Pink
Process of titration
- Acid is added to alkali through a burette until indicator changes color
- Alkali is in a conical flask and is constantly swirled
- Slowly let the acid in drop by drop until a color change