Studied by 14 peopleAtom
Smallest piece of an element
Element
Substance made of 1 type of atom. Listed on the Periodic Table
Compound
Substance made of 2 or more elements chemically joined
Pure
Substance made of 1 type of particle
Mixture
Two or more different particles not chemically joined in a space e.g salt water, air
Molecule
Particle made of more than one atom chemically joined. The elements are usually non-metals. There are weak forces of attraction between molecules.
Particles
General name for any small piece of matter. Can be atoms or molecules (or ions).
Periodic Table
List of all known elements with their symbols.
Formula
How chemists show the combination of elements in a particle e.g CuSO4 or Na
NO3
nitrate
SO4
sulfate
What is in an atoms core?
protons, neutrons
proton charge and atomic mass
+,1
neutron charge and atomic mass
no charge,1
electron charge and atomic mass
-,0
What is the electron filling rule?
2,8,8,7
What is an ion?
An ion is formed when an atom gains or loses an electron
An ion is negatively charged if
it gains an element
An ion is positively charged if
it loses an electron
Physical change
Particles are rearranged but no new particles are made e.g melting, dissolving
Chemical Reaction
atoms in particles rearrange to form new particles
Signs of a chemical reaction
Gas produced, colour changing, temperature change, reactants used up, new substance appears
Signs of physical changes
Produced gas (if boiling or evaporating), temporary colour change, temperature change, change of state
Solute
The substance that dissolves
Solvent
The substance the solute dissolves in
Soluble
Something can be dissolved
Insoluble
Cannot be dissolved
Solution
The mixture of the solvent and the solute
Diffusing
The gradient of a substance through air or water from high concentration to low concentration
Solubility
The maximum amount that can be dissolved in a solvent at a particular temperature
t or f, if you dissolve 40cm3 of salt in 50cm3 of water the volume will be 90cm3
true
t or f, if you dissolve 1g of salt in 200g water the mass will be 200g
false
independent variable
what changes
dependent variable
what you measure
control variable
doesn’t change
Signs of evaporation
Happens at any temperature, only on the surface of a liquid, no bubbles, slow process, cools down a liquid
Signs of Boiling
Happens at a specific temperature, can happen throughout the substance, bubbles of gas are seen, quick process, constant temperature
Why does evaporation happen?
Is evaporation faster at higher temperatures?
Yes
t or f evaporation takes place in all of these places: sea, lake, plants, ground
true
In the water system how does water change?
Evaporation and condensation
In the water system where is water stored?
ocean/sea, lake, river, stream, groundwater
In the water system where does water move?
rivers and streams (watershed), surface run off, percolation through soil and rocks, ground water
saturated solution
a solution where no more solute can dissolve
Note
Flashcard