Paper 1- Inorganic Chemistry Flashcards
What are the Group 1 metals known as
alkali metals
What are simple reactions used to work out
- used to work out if an element is part of the same family as other elements
- elemnts of the same family will react in a similar way
alkali metal + water=
metal hydroxide + hydrogen
alkali metal + oxygen =
metal oxide
Do group 1 elements become more/ less reactive down the group
-more reactive
lithium + oxygen =
lithium oxide
potassium + oxygen =
potassium oxide
sodium + oxygen =
sodium oxide
Why do group 1 elements become more reactive as you go down the group
- group 1 has 1 electron in outer shell
- so as you go down the group the outermost electron becomes further away from the nucleus
- so attraction between outermost electron and nucleus becomes less
What are the Group 7 metals known as
The Halogens
What occurs as you go down group 7
- higher boiling point
- elements have a darker colour
- less reactive
What is chlorine
- fairly reactive,
- poisonous green gas
What is bromine
- poisonous red-brown liquid
- gives off orange vapour at room temp
What is iodine
- dark grey crystalline solid
- gives off purple vapour when heated
Why do group 7 elements become less reactive as you go down the group
- halogen atom needs to gain 1 electron
- the easier it is for the halogen atom to attract an electron, the more reactive the halogen will be
- it becomes harder to attract the extra electron to fill outer shell when its further away
- hence why as you go down group 7, halogens become less reactive
Definition of a displacement reaction
when a more reactive element displaces (pushes out0 a less reactive element from a compound
Definition of oxidation
a loss of electrons
Definition of reduction
a gain in electrons
Definition of oxidising agent
-accepts electrons and gets reduced
Definition of reducing agent
-donates electrons and gets oxidised
Give an example of a halogen displacement reaction
describe what is occurring in the reaction
chlorine + potassium iodide-> iodine + potassium chloride
-chlorine is more reactive than iodine so the iodine is displaced from the salt
- chlorine is reduced
- iodine is oxidised
Definition of a redox reaction
-reactions where reduction and oxidation happen at the same time
What are the 4 gases in the atmosphere
and what % of these gases are in the air
- 78% Nitrogen
- 21% Oxygen
- nearly 1% Argon
- 0.04% Carbon dioxide
What 2 things can be used to investigate the proportion of oxygen in the atmosphere
- iron
- phosphorus
How can iron be used to investigate the proportion of oxygen in the atmosphere
-describe the steps in the practical
- soak iron wool in acetic acid
- then push the wool into a measuring cylinder and invert the measuring cylinder into a beaker of water
- record starting positions of water using scale on measuring cylinder
- level of water in measuring cylinder will rise
- as iron reacts with oxygen in air to form iron oxide
- leave meausring cylinder for a week
- record finishing position of water
how do you calculate the % of oxygen in the atmosphere
start volume - final volume/ start volume x100
How can phosphorus be used to investigate the proportion of oxygen in the atmosphere
-describe the steps in the practical
- place phosphorus in tube and attach glass syringe at either end
- fill one syringe with air and leave the other empty
- heat phosphorus using syringes to pass air over it
- phosphorus will react with oxygen in air to make phosphorus oxide
- as it reacts the amount of air in syringe will decrease
- measuring start and final volumes of air using scale on one of the syringes
What is formed when an element is burned in the air
reacts with oxygen to form an oxide
How does magnesium react with oxygen
- burns with a bright white flame in air
- white powder is formed-
How does hydrogen react with oxygen
- very easily
- orangey/yellow flame
- only product = water
How does sulfur react with oxygen
- burns with a pale blue flame
- produces sulfur dioxide
What does the thermal decomposition of metal carbonates produce
carbon dioxide
metal oxide
What is copper carbonate
what will it decompose to form
- green powder
- will easily decompose to form carbon dioxide and copper oxide
How do you carry out a thermal decomposition experiment
- place copper carbonate in a test tube with a bung
- coming out of the test tube is a tube that is connected top another test tube which collects the CO2 gas
What is Carbon dioxide
a greenhouse gas
What is the temperature of the earth a balance between
the heat it gets from Sun
and heat it radiates back out to space
What do gases in the atmosphere do
what are they often known as
gases such as CO2, methane, water vapour, naturally act like an insulating layer
greenhouse gases
Name 2 examples of human activity which affects the amount of carbon dioxide in the atmosphere
- deforestation- fewer trees means less CO2 is removed from atmosphere via photosynthesis
- burning fossil fuels- carbon that was ‘locked up’ in these fuels is being released as CO2
What is increasing CO2 linked to
Climate Change
Definition of climate change
the earth’s temperature increasing
What is the strongest acids PH
0
What is the strongest alkalis PH
14
What is a neutral substances PH
7
What are universal indicators used for
to measure the approximate pH value of an aqueous solution
What does litmus paper test
whether a solution is acidic or alkaline as it changes colour about PH7
What colour is litmus paper in acidic solutions
red
What colour is litmus paper in neutral solutions
purple
What colour is litmus paper in alkaline solutions
blue
What colour is phenolphalein in acid
-what colour is phenolphalein in alkali
colourless in acid, pink in alkali
Colours of methyl orange?
red in acid and yellow in alkali
Acid + ammonia =
ammonium salt
acid + metal hydroxide =
salt + water
acid + metal oxide =
salt + water
Acid + base =
salt + water
What is neutralisation?
reaction between an acid and base
Name 4 different types of indicators.
Universal indicator, methyl orange, phenolphthalein, litmus (paper)
How can the pH of a solution be found?
By using an indicator.
What is an acid?
A substance that produces H+ ions in water and has a pH less than 7.
Explain the process of titration in detail. (using hydrochloric acid and sodium hydroxide as an example)
- Using pipette & pipette filler add some alkali (about 25cm3) to conical flask with 2/3 drops of indicator
- Fill a burette with acid & do this below eye level
- Using burette add acid to alkali a bit at a time & give conical flask a regular swirl
- Indicator changes colour when all alkali has been neutralised (e.g phenolphthalein = pink in alkalis but colourless in acids)
- record volume of acid used to neutralise alkali
- repeat process for reliable results
What is the ionic equation for neutralisation?
H⁺ + OH⁻ → H₂O
What is a salt?
An ionic compound formed during a neutralisation reaction (reaction between an acid & a base)
What is an alkali?
A soluble base that produces OH- ions in water and has a pH above 7.
What does how you make a salt depend on?
whether its soluble or insoluble
Which nitrates are soluble?
All nitrates
Which sulfates are soluble?
Most of them
Which sulfates are insoluble?
Lead, barium and calcium sulfate
Which carbonates are soluble?
Sodium, potassium and ammonium carbonates
Which carbonates are insoluble?
Most of them
Which hydroxides are insoluble?
Most of them
Are common salts of sodium, potassium and ammonium soluble or insoluble?
soluble
Which common hydroxides are soluble?
sodium, potassium and calcium
Are common chlorides soluble or insoluble?
soluble
Which common chlorides are not soluble?
silver chloride and lead chloride
What can you use to make a pure, dry sample of an insoluble salt?
precipitation reaction
How do you produce an insoluble salt?
By reacting two soluble salts together
How do you make insoluble lead sulphate?
- add 1 spatula of lead nitrate to test tube
- add deionised water to dissolve it & shake thoroughly until its all dissolved
- in seperate test tube do the same with magnesium sulfate
- then tip the 2 solutions into small beaker & stir so its all mixed- lead sulfate should precipitate out
- fold filter paper in a filter funnel & put into conical flask
- pour contents of beaker into filter paper
- swill out beaker with more deionised water & tip into filter paper
- rinse contents of filter paper with deionised water
- scrape lead sulfate onto fresh filter paper & leave to dry in an oven
Explain the process of making hydrated copper(iii) sulfate crystals using dilute sulfuric acid.
1) Heat up the dilute sulfuric acid in water bath in a fume cupboard
2) The add base to acid- Add copper oxide until it’s in excess and keep stirring it.
3) Filter off excess solid- leaving you with a solution with just the salt & water
4) Heat the solution using Bunsen burner to evaporate some of the water
5) Leave solution to cool and allow salt to crystallise so that hydrated copper crystals can form.
How do you test for chlorine?
Chlorine bleaches damp blue litmus paper turning it white
How do you test for oxygen?
relights a glowing splint
How do you test for carbon dioxide?
carbon dioxide turns limewater cloudy
How do you test for hydrogen?
hydrogen makes a squeaky pop with lighted splint
How do you test for ammonia?
Ammonia turns damp red litmus paper blue
What can you use to test for water?
copper sulfate crystals
What happens when copper sulfate is bound to water?
blue crystals form
What happens if you heat blue hydrated copper sulfate crystals?
drives water off, leaving a white anhydrous copper sulfate powder
What happens when you add a few drops of water to the white copper crystals
you get the blue crystals back again
What should you do if you want to test for the presence of water?
-add anhydrous copper sulfate and see if the white powder turns blue
How do you know if water is pure?
pure water will always:
boil at 100 degrees
freeze at 0 degrees
