Chemistry Flashcards
How do you calculate the retention factor (Rf)?
distance travelled by sample / distance travelled by solvent
Describe a displacement reaction
Occurs when a react metal is added to a dissolved compound of a less reactive metal.
How can you find the rate of reaction?
Measure either the rate at which a reactant is used up
or
the rate at which one of the products is formed.
Describe the process of covalent bonding
Occurs when non-metals react with each other by sharing electrons.
What is a mixture?
A mixture contains more than one element or compound.
What is a compound?
Substance made from different elements bonded together.
Define an element.
A substance made from only one type of atom.
Name the following elements:
Br2
Cl2
F2
I2
N2
Bromine
Chlorine
Flourine
Iodine
Nitrogen
Name the properties and group of noble gases.
Group 18
Unreactive
Low melting/boiling point.
Monoatomic
Describe an endothermic reaction.
A reaction which takes in heat from its surrounding, the products have more energy than the reactants.
Describe an exothermic reaction.
A reaction which gives off heat to its surrounding. Products have less energy than the reactants.
Name factors affecting the rates of reaction.
Concentration
Temperature
Surface area
Catalysts
What elements are in group 1?
Alkali metals with 1 electron in outer shell.
What elements are in group 2?
Alkaline earth metals with 2 electrons in outer shell.
Name the parts of the atomic structure
Nucleus
Shells
Electrons
What is the mass number of an element?
The mass number is the number of protons and neutrons in an atom.
What is the atomic number of an element?
The number of protons in the nucleus.
How would you find the number of electrons in an element?
You would look at the number of protons.
The number of protons is the same as the number of electrons.
Why do reactions happen quicker at higher concentrations?
Because there is a greater number of particles to collide, making for more successful collisions.
What is a catalyst?
It is a substance that affects the rate of reaction without being used up in the reaction itself.
What are bond energies
Bond energies are a measure of the average bond strength for a particular covalent bond.
Describe the process of electrolysis
The process where a molten ionic substance is decomposed by an electrical current.
What are the relative atomic masses and charges of subatomic particles?
Protons 1 mass / +1 charge
Neutrons 1 mass / 0 charge
Electrons negligible / -1 charge
What are some properties of giant covalent bonds?
High melting/boiling point
Graphite conducts electricity
diamond and silicon is very hard.
What do amino acids consist of?
Carboxyl group -COOH
Amino group NH2
Organic R group
What are the key features of polymerisation?
Small reactant alkene molecules are unsaturated called monomers.
The large product molecule is saturated called a polymer.
Define a base.
A base is a substance that can accept H+ ions or the ability to form OH-.
Sometimes called alkalis
Describe the process of ionic bonding
Occurs when a metal reacts with a non-metal.
Metals lose electrons and non-metals gain electrons.
Creating an ionic bond.
Describe the properties of ionic compounds.
Solids at room temperature.
Strong overall attraction.
Do not conduct electricity.
Many compounds dissolve in water.
Define an acid.
An acid is a substance which has the ability to donate H+ ions.
Define activation energy.
The minimum amount of energy for particles to successfully react upon collision.
How do you calculate the % composition by mass of a compound.
Number of atoms of compounds / Mr of compound.
How to calculate number of moles of a molecule?
Mass / Molar mass
Mass must always be in grams.
What is Avogadro’s constant?
It gives the number of particles in 1 mole.
value of 6.022x10^23
Describe the properties of halogens.
Group 17
Non-metals
Poor conductors
Low melting/boiling point.
Define hydrocarbons.
Compounds which consist of only hydrogen and carbon.
Give some examples of hydrocarbons.
Ethene
Butane
Methane
Octane
What ions are attracted to the cathode during electrolysis?
+ ions are attracted to the cathode which gains electrons.
What ions are attracted to the anode during electrolysis?
-Ions are attracted to the anode which loses electrons.
What are some physical properties of group 1 alkali metals?
Shiny solids at room temp
Low melting/boiling point
Soft metals
Good conductors
How would you calculate the percentage yield?
Actual yield / predicted yield * 100
What is an alloy?
An alloy is two or more metals mixed together to combine properties.
What do proteins consist of?
Proteins are formed from long chains of amino acids, joined by amino linkages.
What are the chemical properties of group 1 alkali metals?
Very reactive with oxygen/water.
react with non-metals to form ionic compounds.
What are alkanes?
Series of hydrocarbons with no functional group.
Methane and ethane.
What are the limitations of bond energies?
Just an average value so not specific.
Can only be calculated for reactions in a gaseous state,
How do you calculate enthalpy change?
Sum of energy in - sum of energy out.
What’s a key point to remember of distillation?
The particles are closer/further away from each other depending on which state the solution is in.
What is dentrification?
The conversion of nitrates into nitrogen gas.
What are alcohols?
Homologous compounds that contain hydroxyl group.
What do alkenes have at least one off?
There is at least one carbon to carbon double bond.
What are the three main types of extractions of metals from ores?
Reduction with carbon.
Molten by electrolysis
Reduction of ore with a more reactive metal.
Name the following formulae:
HCL
HNO3
H2SO4
CH3COOH
Hydrochloric acid
Nitric acid
Sulfuric acid
Ethanoic acid
Describe collision theory.
For two particles to collide, they must collide at the correct orientation and have sufficient energy.
What is enthalpy change?
it is the amount of heat given out or taken in during a reaction carried out.
Name the following formulae:
NH3
CO2
CO
NO2
SO3
Ammonia
Carbon dioxide
Carbon monoxide
Nitrogen dioxide
Sulphur trioxide
Name the properties of hydrogen.
An element
Produced when metal reacts with water/alcohol.
Burns with a pop when ignited.
Name the properties of oxygen.
Testing oxygen - glowing split will relight.
It is an element.
Why do reactions happen quicker at higher temperatures?
The particles will have more kinetic energy so more frequent successful collisions.
What are some characteristics of carbon dioxide?
Testing - extinguishes a lit splint.
Limewater turns cloudy in presence of CO2.
How would you test for carbonate ions.
This can be tested using limewater which turns cloudy in presence of CO2.
How would you test for halide ions?
It will react with silver if there are halide ions present.
What are the distinct colours of each silver halide participate?
Sliver iode goes Yellow
Silver chloride goes white
Silver bromide goes cream
What’s the specific order you test for unknown ions?
1st - carbonates with dilute acid
2nd - presence of sulphate ions
3rd - halide ions using silver.
