chapter 1: experimental chemistry Flashcards
SI unit of time
second (s)
SI unit of temperature
kelvin (K)
SI unit of length
metre (m)
SI unit of mass
kilogram (kg)
SI unit of volume
cubic metre (cm^3)
WATER DISPLACEMENT METHOD
- what is the solubility of gas in the water?
- what is the density of gas?
- an example of the gas?
- insoluble to slightly soluble
- density does not affect gas collection
- hydrogen, oxygen, carbon dioxide
DOWNWARD DELIVERY
- what is the solubility of gas in the water?
- what is the density of gas?
- an example of the gas?
- can be soluble to insoluble
- denser than air
- chlorine, hydrogen chloride, sulfur dioxide
UPWARD DELIVERY
- what is the solubility of gas in the water?
- what is the density of gas?
- an example of the gas?
- can be soluble or insoluble
- less dense than air
- ammonia
what is a mixture?
a mixture consists of two or more substances that are not chemically combined
what are the different mixtures to separate (eg solid, liquid, gas)?
- solid-solid mixtures
- solid-liquid mixtures
- liquid-liquid mixtures
SEPARATING SOLID-SOLID MIXTURES
using magnetic attraction
- how does it work?
- examples of magnetic substances?
- magnetic substances can be separated from non-magnetic substances
- examples are iron, cobalt, nickel and some alloys
-> waste in a landfill can be sorted using magnetic attraction
SEPARATING SOLID-SOLID MIXTURES
sieving
- how is it separated?
a sieve is used to separate solids with different particle sizes
SEPARATING SOLID-SOLID MIXTURES
using suitable solvents
- how to separate the solvents?
- solids of different solubility in the solvent can be separated
- solvent: liquid that dissolves in the solvent
- solute: solid that dissolves in the solvent
SEPARATING SOLID-LIQUID MIXTURES
filtration
- how does it separate?
- where can it not be dissolved in (insoluble / soluble, solid / liquid)
- separates an insoluble solid from a liquid
- an insoluble solid is one that is unable to dissolve into the liquid it is placed in
-> filtrate: liquid that passes through the filter
-> residue: solid that remains on the filter
SEPARATING SOLID-LIQUID MIXTURES
evaporation to dryness
- how is it separated?
- separates a dissolved solid from its solvent. the mixture is heated until all the solvent has vaporised
SEPARATING SOLID-LIQUID MIXTURES
crystallisation
- how is it separated?
- separates a pure solid from its saturated solution (meaning of saturated solution: in which no more solute can be dissolved)
SEPARATING SOLID-LIQUID MIXTURES
simple distillation
- how is it separated?
- separates a pure solvent (liquid) from its solution
meaning of miscible liquids
- liquids that form a uniform solution
meaning of immiscible liquids
- liquids that do not form a uniform solution
SEPARATING LIQUID-LIQUID MIXTURES
chromatography
- how is it separated?
- separates a mixture of substances which have different solubilities in a given solvent
- components in a mixture can be identified by comparing chromatograms of the sample with that of pure substances
SEPARATING LIQUID-LIQUID MIXTURES
fractional distillation
- how is it separated?
- separates miscible liquids with different boiling points
PURITY OF SUBSTANCES
colourful crystals
- how does a pure crystalline aluminium oxide appear as (appearance, colour)
- it appears as coloured gemstones in the presence of impurities
how can the purity of substances be determined?
- a pure substance has a specific melting and / or boiling point under fixed conditions
- mixtures melt or boil over a range of temperatures
