CHEMISTRY P7 Flashcards
What is the definition of molecules
Two or more atoms bonded together
What will a compound be made out of
A metal and a non metal or 2 non metals
What is the configuration of metals and non metals in an equation
The metal will always go first if there is no metal the non metal element that is closest to the left will go first
What happens when a compound is made (two elements)
- The metal or non teal closest to the eft will go first if
- The non metal ending changes to ‘ide’ e.g chlorine to chloride
What happens when there is 3 elements creating a compound
If the last element is oxygen you add ‘ate’ to the end
e.g CaCO₂ - calcium carbonate
If the last element is not oxygen you follow the rule of two elements
e.g OH- hydroxide
Which comes first in a word equation
In a word equation the reactants come before the products
e.g Sulphuric acid + magnesium = magnesium sulphate + hydrogen
What can you not do with atoms
Atoms cannot be created nor destroyed but they can be rearranged
How do you balance an equation
The number of each type of atom is the same number of atoms of both sides of the equation
e.g. 2mg+ O₂ = 2MgO₂
What is displacement
Displacement is when a more reactive element takes the place of a less reactive metal
e.g Na+ LiCl = NaCl + Li
What is the difference between a mixture and a compound
In a mixture the elements are not bonded as in a compound the elements are chemically bonded together
Does the composition of an element change in a mixture and compound
Mixture - can vary
Compound - stays the same
Does the Chemical properties of an element change in a mixture and compound
Mixture - stay the same
Compound - changes
How easy is the separation of elements in a compound and a mixture
Mixture - easy
Compound - difficult
What should you always make sure you do when balancing equations
Always bring it too it’s simplest form
How do you separate a soluble from an insoluble solid
- set up
- spoon copper sulphate into beaker add water and mix
- wait until most of sulphate is dissolved
- pour solution into funnel lined with filter paper and wait for the insoluble solid to collect
- pour solution into evaporating dish
- evaporate half of the water then leave to crystallise
What is a solution
A solution is a mixture of a solutes dissolved into a solvent
solute
soluble solid
solvent
Liquids that allow solutes to dissolve
saturated solution
when all the gaps in a solvent is filled and nothing else can be dissolved
What circumstance can solubility increase
temperature
What happens when you cool a saturated solution
crystals of a salute begin to form as the gaps get smaller
How do you separate two liquids with two different boiling points
- heat up the mixture
- let the mixture evaporate
- Use the thermometer to work out the boiling points ( the liquids will evaporate and different times as they have different boiling points)
4 cold water cols down the vapour and condenses the liquid into pure liquid
distillation
a technique which allows you to separate a liquid from a mixture
chromatography
a technique used to separate soluble sounds from a mixture
How does chromatography work
- A solvent (water) is used to dissolve ‘carry’ the solutes along the stationary phase( piece of paper)
- The different solutes have different solubilities allowing them to separate
method of chromatography
1.Draw a pencil line (insoluble) near the bottom
2.put a dot of the mixture on it
3. place paper in a beaker with a minimal amount of water
What is the first model of the atom
Daltons model 1803
No particles
What is the second model of the atom
J.J Thompson 1897
Negative particles called electrons spread evenly with protons
What is the third model of the atom
Rutherford model 1905
Discovered nucleus using gold foil experiment
What is the fifth model of the atom
Bohr model 1908
Electrons orbit the necleus on different energy levels
What is the model we use of the atom today
Orbital model 1932
Chadwick and Rutherford
Discovered neutrons
What is the radius of an arom
0.1nm
what is the radius of the necleus
1/1000 of the atom
what is the top number on an element called
atomic mass
protons and neutrons added together
what is the bottom number on an element called
atomic number
Number of protons
How do you know what group an element is in
the outer number of electrons equals the group it is in
How do you know what period an element is in
The number of energy levels
What is an iscotope
Te same element with the same number of protons and electrons but a different number of neutrons
