Nat 5 Chemistry unit 3 - chemistry in society

How are electrolytes formed

Formed when soluble ionic compounds dissolve in water

Do two metals connected in a cell produce a voltage

Yes

Why does the electrolyte have to be an ionic solution?

To allow for conduction

How do the electrons flow in the electrochemical series?

The electrons always flow from the metal higher in the electrochemical series to the metal lower in the electrochemical series

What happens to the electrons of the metals higher up in the electrochemical series?

They lose electrons

What happens to the electrons of the metals lower down in the electrochemical series?

They gain electrons

What is the correlation between the metals and voltage in the electrochemical series

the further apart the metals are the larger the voltage

what happens to the voltage if the same metal type reacts redox chemistry

the voltage is 0

how is a metal oxide formed

when metals react with oxygen

what is oxidation

the process of losing electrons

when does oxidation occur

when a metal forms a compound

what is reduction

the process of gaining electrons

when does reduction occur

it a occurs when a non metal forms a compound

what is a redox equation

when we combine the oxidation and reduction equations. we cancel out the electrons on each side of the equation

what do you do to predict the voltage of a chemical cell

depending how far apart they are so if they are really far apart the voltage will be high if they are quite close together then the voltage is low and if its in the median then the voltage shall be medium

name the main properties of metals

- strength = how a strong a metal is

- malleability = they can be shaped into certain shapes or rolled into flat sheets

- conductivity electricity = all metals are good conductors of electricity

- conduction of heat = they are able to conduct heat well

-density = this is the mass of the substance in a given volume, certain metals are used for certain things depending on their density

why do metals conduct

have delocalised electrons which are free to move throughout the structure and carry the current

what is the reactivity series

is like electrochemical series but in order of the most reactive to the least

what are the three types of radiation

alpha, beta, gamma

what is nuclear decay with the emission of a alpha particle

it means that a helium nucleus is created (mass = 4, atomic number = 2) along with a radioisotope, the atomic number on the LHS is equal to the sum of the atomic numbers on the RHS this is the same for the mass

what is nuclear decay with the emission of a beta particle

it means that a beta particle is created (mass = 0, atomic number = -1) along with a radioisotope, the atomic number on the LHS is equal to the sum of the atomic numbers on the RHS this is the same for the mass. the image is incorrect the nitrogen mass is meant to be 9 and beta is meant to be negative 1

why does nuclear decay occur

as they are unstable atoms and must become more stable by releasing energy and radiation

what is the penetrating power of alpha, beta and gamma

alpha - can't penetrate paper

beta - can penetrate a sheet aluminium

gamma - can't penetrate a few centimetres of lead

what is the half-life

is the time taken for the mass or activity of a radioactive element to half

what are the properties of ammonia

- clear and colourless gas

- it has a sharp pungent smell

- it turns pH paper purple

what does metal + water make

metal hydroxide + hydrogen

what does a metal + dilute acid make

salt + hydrogen

What is metallic bonding?

The electrostatic force of attraction between positively charged ions and delocalised electrons

what are the 3 methods to extract metal from its ore

- heat alone

- heating with carbon or carbon monoxide

- electrolysis

what metals is heating alone used to extract it from its ore

Ag, Au, Hg any metal at the bottom of the electromechanical series

when is heating with carbon used to extract metal from its ore

in the middle of the electromechanical series (Cu, Pb, Sn, Fe,Zn)

when is electrolysis used to extract a metal from its ore

more reactive metals , above alluminium

what is electrolysis

Electrolysis is the processes that uses electricity to break down ionic compounds into elements

why must a dc supply be used for electrolysis

to correctly identify the products

what is an ion bridge

a bridge used to link electromechanical cells, ions move across the bridge to complete an electric socket

what are the nutrients that plants require in fertalisers

- nitrogen

- phosphorus

- potassium

What are fertalisers?

Fertilisers are substances which restore elements, essential for healthy plant growth, to the soil.

Ammonia solutions react with acids to form soluble salts. what is the equation for this

ammonia solution + an acid an ammonium salt + water

What is the haber process

making ammonia from nitrogen and hydrogen using an iron catalyst

what is the equation for the haber process (fertalisers)

N2+3H2 ⇌ 2NH3

What equation is this for N2+3H2 ⇌ 2NH3

Haber process

What process is this equation for 4NO2 + O2 + 2H2O → 4HNO3.

The Ostwald process

What's the equation for the Ostwald process

4NO2 + O2 + 2H2O → 4HNO3.

what are things that have to be used to make the haber process economical and efficiant

TemperatureModerate/Low temperature - reaction too slow: High temperature - ammonia decomposes.

Pressure High - This increases the yield of ammonia.

Catalyst - Iron (Fe) speeds up the production of ammonia, saving energy costs.

Condenser - This cools the reaction down, turning ammonia into a liquid which is easier to extract.

Recycled reactants - Unreacted nitrogen and hydrogen are returned to the reaction, saving money.

what is the ostwald process

oxidising ammonia to make nitric acid. A platinum catalyst is used in this process

What is polymerisation

Is the name given to a chemical reaction in which unsaturated monomers are joined forming a polymer

What are plastics an example of

A Polymer

What is a polymer?

Longchain molecules formed by joining together a large number of small molecules called monomers

How to show addition polymers in a question

Remove the middle double carbon bond and put it on the outside of both sides of the monomer

How to name a monomer/polymer

Put poly before the name of the monomer

What is a repeting unit

The shortest section of the polymer chain which if repeated would yield the complete polymer chain

What is the catalyst in the production of ammonia

Iron

What is the catalyst in the Ostwald process or the production of nitric acid

Platinum

How to name salts that carboxylic acids create

1st word - base

2nd word - acid

ends with oate

What values do you sub into the formula E=cm^t

Why doesn't the experiment work when testing the energy produced from a flame

- energy getting lost due to surroundings

How to name a polymer

Add poly to the start of the monomers name

What is an example of a natural polymer

Starch, it is made from glucose monomers

What does precipitate mean

A solid that forms from a solution during a chemical reaction.

How do you check if something precipitates

- swap the two last names

- check solubility

- if it's insoluble it precipitates

What do flame tests show us

Identify the metals in a sample

What is the test for oxygen

Relights a glowing splint

Hydrogen test

When placed in hydrogen gas a flame will pop

What is the test for carbon dioxide

Turns limewater cloudy

What is a qualitative analysis

Any method of analysis used to identify the chemicals in a substance.

What is a quantative analysis

To identify how much of something there is