Unit 3 Flashcards
What happens when monomers join together during addition polymerisation?
Double bond breaks allowing free electrons to bond
What is a repeating unit?
Smallest part of chain that can represent the whole polymer
What are condensation polymers made from?
Monomers with two functional groups in each molecules
What is the condensation polymerisation general equation?
Idol + dicarboxylic acid -> polyester + water
When monomers join together during condensation polymerisation, what molecule is lost?
Water
What three elements provide nutrients for plants?
Nitrogen, phosphorus and potassium (NPK)
What is the haber process used for?
To make ammonia (NH3) from nitrogen and hydrogen
What is ammonia used for?
The making of fertilisers
What catalyst is used in the Haber process?
Iron
What is the Ostwald process?
When ammonia is used to make nitric acid
What are the starting materials for the Ostwald process?
Oxygen and ammonia
How does oxygen and ammonia combine to form nitrogen oxide in the Ostwald process?
In a reaction chamber where the catalyst is platinum
How can percentage mass of an element in a compound be calculated?
% mass = total mass of element/ formula mass X 100%
Describe a metal’s structure
A giant lattice of positively charged metal ions in a sea of delocalised electrons
How does a metal conduct electricity?
Delocalised electrons are free to move around
Metal + water -> ?
Metal hydroxide + hydrogen
Metal + acid -> ?
Salt + hydrogen
Metal + oxygen -> ?
Metal oxide
Which end of the reactivity series is most reactive?
Top
What is oxidation?
The loss of electrons
What is reduction?
The gaining of electrons
Where are most metals found?
In rocks called ores
What metals can be extracted with electrolysis?
Highly reactive, e.g - magnesium, aluminium
How can metals with a medium reactivity be extracted?
Heat with carbon (eg - zinc, iron, tin ,copper)
How could silver or gold be extracted?
Heat alone
When are addition polymers formed?
When lots of small unsaturated molecules (monomers) join together
What is a reducing agent?
An element that causes the reduction of the metal from it’s ore
What does an electrolyte do?
It allows a flow of ions and connects the circuit
Which way do the electrons flow form metal to metal?
High metal in electrochemical series gives electrons to lower metal
What does a bigger gap (in electrochemical series) give?
A higher voltage
What is a redox reaction?
A reaction which involves an oxidation and a reduction reaction
What must balance out in order to write a redox reaction?
The electrons
What is an example of an every day product that uses redox reactions?
Fuel cells and rechargeable batteries
Who is hydrogen often used in fuel cells?
Because only water is produced so there is very little pollution
When does radioactivity occur?
When unstable isotopes of elements spontaneously decay with the emission of radiation and release of energy
What are some examples of background radiation?
Cosmic rays, rocks, the sun
How can radioactivity be measured?
With a Geiger-Muller tube
What is an alpha particle?
A helium nuclei, 2 protons + 2 neutrons
What is the symbol for an alpha particle?
4/2 He ^ 2+
What are the three types of radiation?
Alpha, beta and gamma
What is a beta particle?
Fast moving electrons from the nucleus
What is the symbol for a beta particle?
0/-1 e
What is gamma radiation?
Waves which have no mass
What penetrates alpha radiation?
A sheet of paper
What penetrates beta radiation?
A few mm of aluminium
What penetrates gamma?
A few cm of lead or concrete
When writing nuclear equations what must be equal on both sides?
Mass and atomic number
What is half-life?
The average time taken for the activity of a radioactive substance to decrease by half
How long a half life is safer?
A shorter half life
What can used to find the age of something?
Carbon dating
What is a medical use of radioisotopes?
Gamma can be used for radio therapy
What are some industrial uses of radio isotopes?
Sterilise surgical equipment, ensure correct fill level in packaging foods, gauge thickness in sheet metal
What type of radiation is used in smoke detectors?
Alpha
