C12 - Experimental Techniques Flashcards
What are examples of physical properties? [6]
- luster (shiny)
- hardness
- ductile
- malleable
- melting point
- density
What are examples of chemical properties? [5]
- flammable
- radioactive
- pH
- corrosive
- toxic
In physical change, is the change permanent or temporary? [1]
temporary
In chemical change, is the change permanent or temporary? [1]
permanent
Are new substances formed in physical changes? Where is there change? [2]
- NO
- change only in physical properties
Are new substances formed in chemical changes? Where is there change? [2]
- YES
- change in physical and chemical properties
Is change reversable in physical change? If so, how? [2]
- YES
- by simple physical methods
Is change reversable in chemical change? If so, how? [2]
- NO
Is energy released or absorbed in physical change? [1]
- may or may not be
Is energy released or absorbed in chemical change? [1]
- YES
- during chemical change
Can the original substance of a physical change be obtained again? If so, how? [2]
- Most of the time YES
- simple physical methods
Can the original substance of a chemical change be obtained again? If so, how? [2]
- NO
How do we know a chemical reaction has taken place? [6]
- change in colour
- change in odour
- warming or cooling
- release of light
- formation of bubbles
- formation of a precipitate
What is a mixture? [3]
not chemically bound physical and chemical properties (remain) those of the component elements/substances
What is a compound? [2]
chemical reaction has occurred and new substance has new chemical and physical properties.
What is the appropriate apparatus for the measurement of time? [1]
stop-watches
What is the appropriate apparatus for the measurement of temperature? [1]
thermometer
What is the appropriate apparatus for the measurement of mass? [1]
balance
What is the appropriate apparatus for the measurement of volume? [4]
- burettes
- volumetric pipettes
- measuring cylinders
- gas syringes
What is a solvent? [2]
liquid the solute dissolves in
What is a solute? [2]
substance that is dissolved in a solvent
What is a solution? [2]
mixture of one or more solutes dissolved in a solvent
What is a saturated solution? [3]
a solution containing the maximum concentration of a solute dissolved in the solvent at a specified temperature
What does unsaturated mean? [2]
dissolved solute is below saturated point - more can dissolve
What does saturated mean? [2]
dissolved solute is at saturation point - no more can dissolve
What does supersaturated mean? [2]
dissolved solute is above saturated point - additional solute gathers at the bottom
What is residue? [2]
a solid substance that remains
after evaporation, distillation, filtration or any similar process
What is a filtrate? [2]
a liquid or solution that has passed through a filter
What is crystallisation? [2]
- used to seperate a soluble substance from a solvent
- e.g. removing salt from a salt solution
What is simple distillation? [2]
- used to seperate a solvent from a solution
What is fractional distillation? [2]
- its splits crude oil up into its separate parts, or fractions.
What is filtration? [2]
it is used to separate liquids from insoluble solids
What are examples of pure substances? [2]
- elements
- compounds
What are examples of impure substances? [2]
- mixtures
What is the boiling point like for a pure substance? [1]
- ONE boiling point
What is the boiling point like for an impure substance? [1]
- range of boiling points
How is paper chromatography used? [2]
- used to separate mixtures of soluble coloured substances, using a suitable solvent
What is the solvent front? [1]
Where the solvent gets too
Why is the base line above the solvent? [1]
- so that it doesn’t get dissolved if below base line.
Why does each compound move up different points? [1]
- they have different solubilites
What does it mean if the substance in more soluble? [2]
the high it moves up with the solvent
What is Rf? [2]
ratio of how far your chemical has moved / how far your solvent moved
Rf = [2]
far compound moved / solvent distance
On chromotography paper, if there was only one point, what does that mean? [1]
PURE substance
- element
- compound
On chromotography paper, if there were multiple points, what does that mean? [1]
IMPURE substance
- mixture
