Unit 1.1 - The Nature Of Substances And Chemical Reactions Flashcards
What is the mass number/Atomic mass/Ar
Mass of Protons + neutrons of an atom
What are elements
Substances that cannot be broken down into simpler substances. They are substances made up of only one type of atom
How to calculate atomic number
Number of protons/electrons
How to calculate the Number of Neutrons
Mass number - atomic number
What are isotopes
Isotopes are atoms of the same element with the same number of protons but a different number of neutrons
What are compounds
Compounds are substances made of two or more different types of atoms that are chemically joined. Compounds Are difficult to separate
True/false.
Compounds have the same properties to the elements that made it
False-the properties of compounds can be completely different to the elements that made it
How to work out Ar /relative atomic mass
Example: chlorine
75% - 35 Cl
25% - 37 Cl
(75x35) + (25x37)
————————-
100
How to work out formulae
Aluminium oxide
Al3+. O2-
Al2O3
What does Mr stand for
Relative molecular mass
How to work out Mr
H2O
2x1 + 1x16 = Mr of 18
How to work out percentage composition by mass
Example: what percentage of NH3 is N
Mr(NH3)=17
1x14
—— x 100 = 82%
17
What is a mixture
Adam/molecules in mixtures I’m not chemically joined therefore can be easily separated. Mixtures can be in any proportions and they do not lose their original properties.
What physical processes can separate mixtures
Filtration, evaporation, chromatography, distillation
Give a use for each method of separating a mixture
Evaporation, filtration, chromatography, distillation 
Evaporation = changes liquid into gas
Filtration = filtrate liquid from substance
Distillation = changes liquid into gas and collects gas
Chromatography = separates dyes
What happens to atoms in a chemical reaction
Atoms are rearranged but none are created or destroyed, Therefore the mass of the reactants would be the same as the mass of the products
Cheat for writing equations
Signs
know
workout
balance
How to write equations
Example:
Magnesium + oxygen => Magnesium oxide
S. + =>
K. Mg + O2 =>
W. Mg + O2 => MgO
B. 2Mg + O2 => 2MgO
Cheat for diatomic substances
Have no fear of ice cold beer
Hydrogen
Nitrogen
Fluoride
Oxygen
Iodine
Chlorine
Bromium
Useful acid formulaes
Sulphuric acid-H2SO4
Nitric acid - HNO3
Hydrochloric acid HCl
Four types of chemical reactions
Exothermic, endothermic, neutralisation, reversible
Properties of types of chemical reactions
Exothermic, endothermic, neutralisation, reversible
Exothermic-gives of heat
Endothermic a-takes in heat (Cold on Surface)
Neutralisation-where acids and bases react to form neutral products
Reversible-can be reversed dependant on conditions
Mass, atomic mass, moles triangle
Mass
Ar. Moles
How to work out empirical formulae
Example : 0.62 g phosphorus combined with 0.48 g of oxygen
Elements P. O
Mass. 0.62. 0.48
Ar. 31. 16
Moles. 0.02. 0.03
Ratio. 2. 3
Formula. P2. O3
P2O3
How to work out reacting masses
Example: 2Mg + 02 => 2MgO
Elements. Mg. MgO
Mass. 6. ? => 10
Ar. 24. 40
Moles. 0.25. X1>. 0.25
Ratio. 2. X1> 2
What is the valency of an element
How many electrons are lost/gained when an atom turns into an ion
What is an ion
An atom with an electrical charge
What happens to turn an atom into an ion
An electron is lost/gained
Two uses of gas chromatography
Find exact amount & see forged to banknotes
Advantage of gas chromatography over paper chromatography
Tells the exact amount
Explain why the process of chromatography is able to separate dyes
All the chemicals have different solubilities
Equation for Rf
Distance from baseline to compound spot
———————————————————— = Rf
Distance from baseline to solvent front
Equation to work out the percentage yield
Theoretical mass
————————- x 100 = %yield
Actual mass
Reacting masses ratio
Always 1:1
What is a period on the periodic table
Row
What is a group on the periodic table
Column
If an element is in group 2 what does it tell you about that element
It has two electrons in the outer orbit/shell
If an element is in period two what does it tell you about that element
It has two electron orbits/shells in total
How many electrons fit on its first orbit /shell
2
How many electrons fit on every orbit/shell except the first
8
If an element is in group 8/zero what does it tell you about that element
It has a full outer orbit/shell
How to get number of electrons
Atomic number
To get a number of protons
Atomic number

