Introduction Flashcards
Define a chemical reaction
new product formed, usually irreversible
Define a physical reaction
no new product formed, always reversible
What are the signs of a chemical reaction?
colour change
irreversible (usually)
gas released
smell
temperature change
smoke
light given off
new product formed
What are the signs of a physical reaction?
reversible (always)
change of state
dissolving
no new product formed
What happens to atoms in a physical reaction?
atoms change arrangements
What happens to atoms in a chemical reaction?
bonds break, rearrange, bond back together
solid -> liquid?
melting
liquid -> gas?
evaporating
gas -> liquid?
condensing
liquid -> solid?
freezing
solid -> gas?
sublimation
gas -> solid?
deposition
What is an atom?
the smallest part of an element
What is an element?
made up of one type of atom
What is a molecule?
More than one atom chemically bonded
What is a diatomic element?
Molecule of an element made of two atoms
What are some examples of diatomic elements?
N, O, F and down
What are the properties of metals?
shiny
solid at room temp (high mp)
conduct electricity
conduct heat
malleable
sonorous (make sound)
What are the properties of non-metals?
dull
gas at room temp (not all)
non conductive
not malleable
not sonorous
low density
weak
What is a metalloid?
Can have properties of metals and non-metals. Eg Silicon - non metal but can be made to conduct electricity
What is a compound?
more than one type of atom chemically combined
What is a mixture?
more than one substance not chemically combined
What is the chemical test for the presence of water?
Anhydrous copper sulphate turns from white to blue
Cobalt chloride paper will turn from blue to pink
How can you determine if water is pure or not?
measure boiling point - pure water boils at 100ºC
What is diffusion?
movement of particles from an area of high to low concentration as a result of their random movement
How can rate of diffusion be increased?
push particles around
increase temp
increase concentration
What is a solvent?
The liquid that dissolves the solute
What is a solute?
The solid that dissolves in the solvent
What is a solution?
mixture of solvent and dissolved solute
What does saturated mean?
no more solute is able to dissolve
What does insoluble mean?
can not dissolve (in a certain solvent)
What does soluble mean?
can dissolve (in a certain solvent)
What is suspension?
Solution containing undissolved solid (normally floating)
What are the unites to measure solubility?
g per 100g
How would you separate a mixture of inks?
chromatography
How would you separate Ethanol + water?
distillation
How would you separate salt + water?
evaporation
How would you separate sand + water?
filtration
