Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chemistry - Coggle Diagram
Chemistry
Copper Sulfate
- Place some sulfuric acid in a conical flask and warm it in a water bath.
- Add a spatula of copper oxide powder to the acid and stir with a glass rod.
- Continue adding copper oxide powder until there is enough for a reaction to happen.
- Filter the mixture to remove the excess copper oxide.
- Pour the filtrate (copper sulphate solution) into an evaporating basin.
- Heat the copper sulfate solution to evaporate half of the water
- Pour the solution into a watch glass and leave to allow all of the water evaporate.
-
Atom Structure
-
-
JJ Thomson - Plum Pudding Model. The atom is a ball of positive charge with negative electrons embedded in it.
John Dalton published his ideas about atoms in 1803. All matter was made of tiny particles called atoms, tiny spheres that could not be divided.
Ernest Rutherford - 1909 Alpha Particles. New model for the atom called the Nuclear Model in this model, the mass of an atom is concentrated at its centre, the nucleus and the nucleus is positively charged.
-
Energy profile graphs
-
-
reaction profiles include the activation energy, which is the minimum energy needed by particles when they collide for a reaction to occur. The activation energy is shown as a 'hump' in the line, which:
-
-
the overall change in the energy in a reaction is the difference between the energy of the reactants and products.
Avogadro's Constant
-
the number of particles of a substance can be calculated using: the avogadro constant and the amount of substance in mole.
-
Example:
Calculate the number of water molecules in 0.5 mol of water
Number of water molecules =
6.022 x 10^23 x 0.5 = 3.011 x 10^23
mass of atom (g) = Ar of element / Avogadro constant
- Relative atomic mass = Ar of element
Structure and Bonding
-
-
-
Forming Ions - an ion is an atom or group of atoms with a positive or negative charge. Ions form when atoms lose of gain electrons to obtain a full outer shell.
metal atoms lose electrons to form positively charged ions
non metal atoms gain electrons to form negatively charged ions
Bond Energies
-
- add together the bond energies for all the bonds in the reactants - this is the 'energy in'
- add together the bond energies for all the bonds in the products - this is the 'energy out'
- calculate the energy change = energy in - energy out.
Periodic table
-
-
-
modern table:
the elements are arranged in rows, called periods, in order of increasing atomic number.
elements with similar properties are placed in vertical columns, called groups.
Alloys
An alloy is a mixture of two or more elements, where at least one element is a metal. Many alloys are mixtures of two or more metals.
e.g. stainless steel = chromium and iron - hard, does not rust easily.
In an alloy, there are atoms of different sizes.
empirical formula
the empirical formula of a compound is the simplest whole number ratio of atoms of each element in the compound. It is determined using data from experiment and therefore empirical.
e.g- the molecular formula of glucose is C6H12O6 but the empricial formula is CH2O. THis is because we can divide each number in C6H12O6 by 6 to make it simpler whole number ratio.
Energy change
Need to know the mass - or volume of the water that was heated. The temperature change of the water, and the mass or number of moles of the limiting reactant.
-
Electrolysis
Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them.
Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidised. The substance that is broken down is called the electrolyte.
Positively charged ions move to the negative electrode during electrolysis. They receive electrons and are reduced.
-