Section 4 - Inorganic chemistry Flashcards
Why are group 1 metals called the alkaline metals?
.As when they react with water they produce a metal hydroxide solution which is alkaline
What is the trend in reactivity with the alkali metals?
They get more reactive as you go down the group
Why do group 1 metals get more reactive as you go down the group?
.As you go down the group there are more electron shells
.This means it is further away from the nucleus
.This means there is less attraction between the electron shell and the nucleus
.This means the electron is lost more easily which increases reactivity
What is the trend in reactivity with the halogens?
As you go higher in the group they get more reactive
Why does reactivity decrease as you go down group 7?
.In order to get a full outer shell the halogens must gain 1 electron
.As you go up the group there are less electron shells
.This means it is easier to gain an electron which increases reactivity
What is an oxidising agent?
An oxidising agent gets reduced in a reaction and oxidises the other reactant
What is a reducing agent?
A reducing agent donates electrons and gets oxidised in a reaction and reduces the other reactant
What happens in oxidation and reduction?
Oxidation
Is
Loss (of electrons)
Reduction
Is
Gain (of electrons)
What is a redox reaction?
A reaction where oxidation and reduction take place
What happens when magnesium is burned?
.Magnesium burns with a bright white flame in air and forms a white powder
.The powder formed is magnesium oxide
.Which is slightly alkaline when dissolved in water
What happens when hydrogen is burned?
.Hydrogen burns very easily and can be explosive
.The only product is water as a vapour
What happens when sulfur is burned?
.It produces a pale blue flame and produces sulfur dioxide
.This is slightly acidic when dissolved in water
What is pH 0 (red)?
The strongest acid
What is pH 7(green)?
A neutral solution (water)
What is pH 14(purple)?
The strongest alkali
What colours does universal indicator go in acids, alkalies and neutral solutions?
Acid - red
Neutral - Green
Alkaline - Purple
What colours does litmus paper go in acidic, alkaline and neutral solutions?
Acid - red
Alkaline - blue
Neutral - purple
What colour does phenolphthalein go in acidic and alkaline solutions?
Acidic - Colourless
Alkaline - Pink
What colour does methyl orange go in acidic and alkaline solutions?
Acidic - Red
Alkaline - Yellow
Define the term acid
Proton donators
Define the term base
.A substance that can neutralise an acid
What are alkalis?
.Soluble bases
.Proton acceptors
What does an ACID + metal oxide produce?
Salt + water
What does an acid + metal hydroxide produce?
Salt + water
What does an ACID + ammonia produce?
Ammonium salt
What does an Acid + metal carbonate produce?
Salt + water + carbon dioxide
What are the steps to carrying out a titration?
.Using a pipette and pipette filler and around 25cm cubed of alkali to a conical flask
.Add two to three drops of indicator (universal indicator)
.Fill a burette with around 25cm cubed of acid
.Make sure it is BELOW EYE LEVEL
.Slowly add the acid to the alkali a bit at a time and whilst swirling the conical flask
.Slow down when you have nearly reached the end point
.The indicator will change colour (from blue to green if you have used universal indicator)
.Record the volume of acid used from the bottom of the meniscus
.And repeat at least 3 times to ensure reliable results
What is a precipitate?
An insoluble salt
Are common salts like sodium, potassium and ammonium soluble or insoluble
Soluble
Are nitrates soluble or insoluble?
Soluble
Are common chlorides soluble or insoluble?
Soluble except silver chloride and lead chloride
Are common sulfates soluble or insoluble?
Soluble except for lead sulfate, barium sulfate and calcium sulfate
Are common carbonates soluble or insoluble?
Insoluble except for Sodium carbonate, potassium carbonate and ammonium carbonate
Are hydroxides soluble or insoluble?
Insoluble except for sodium hydroxide, potassium hydroxide and calcium hydroxide
How do you make insoluble salts?
.React the two correct soluble salts together
.For example
To make lead sulfate(s) mix lead nitrate(aq) and magnesium sulfate(aq)
How would you make soluble salts?
.Titration
.React an acid that contains the ions you want in the salt with an insoluble base
.For example
.You add copper oxide to warm sulfuric acid to make copper sulfate solution
What colour flame does lithium burn with?
Red
What colour flame does sodium burn with?
Yellow
What colour flame does potassium burn with?
Lilac
What colour flame does calcium burn with?
Orange-red
What colour flame does copper burn with?
Blue-green
What is the colour of a copper precipitate?
Blue
What is the colour of an iron(II) Fe2+ precipitate?
Green
What is the colour of an iron(III) Fe3+ precipitate?
Brown
How would you test for ammonia gas?
Ammonia gas turns damp red litmus paper blue
How would you test for ammonium?
.Add NaOH solution to the sample
.If ammonia is given off ammonium is present
How would you test for carbonates?
-Add dilute hydrochloric acid (HCl) to the sample
-If carbonates are present then carbon dioxide will be released
How would you test for sulfate ions?
.Add dilute hydrochloric acid (HCl) followed by barium chloride (BaCl2)
.If sulfates are present then a white precipitate is formed
How would you test for halides (Chloride, bromide and ioide)?
.Add dilute nitric acid (HNO3) followed by silver nitrate solution (AgNO3)
What colour precipitate do chloride ions form?
White (Silver chloride)
What colour precipitate do bromide ions form?
Cream (Silver bromide)
What colour precipitate do iodide ions form?
Yellow (silver iodide)
Why do you add acid before testing for anions?
To remove carbonate or sulfate ions before the test
How do you test for chlorine?
.Chlorine bleaches damp blue litmus paper white
How do you test for oxygen?
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 a lit splint
How do you test for ammonia?
Turns damp red litmus paper blue
What are the greenhouse gases?
Carbon dioxide
Water vapour
Methane
How does human activity contribute to the amount of CO2 in the atmosphere?
-Deforestation - fewer trees means less CO2 is removed from the atmosphere by photosynthesis
-Burning fossil fuels - Carbon locked up by these fuels is released as CO2
Set up an experiment to find out the reactivity of metals using acid
-Set up 3 boiling tubes and fill them with equal volumes of dilute hydrochloric acid or dilute sulfuric acid
-Then place pieces of magnesium, zinc and iron into separate test tubes
-The speed of the reaction is the rate of which hydrogen bubbles are given off
State the reactivity series
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Hydrogen
Copper
Silver
Gold
When does rusting take place?
When iron comes into contact with oxygen and water
What is the word equation for rusting?
Iron + oxygen + water -> Hydrated iron(III) oxide
What are the ways to prevent rusting?
-Coating with plastic - suitable for small structures
-Oiling - used for moving parts
-Galvanising - Used on ships
What is galvanising?
-As zinc is more reactive than iron
-It will get oxidised instead of the iron
-So a zinc coating is applied to the object to prevent it from rusting
What are the properties of iron, aluminium and copper?
-Dense and lustrous
-Shiny
-Have high melting/boiling points
-High tensile strength
-Malleable
-Good conductors of heat and electricity
What are the uses of Wrought iron?
-used for gates and railings as it’s malleable
What are the uses and properties of aluminium?
-Doesn’t corrode easily
-Oxidises easily to form aluminum oxide which is a nice protective layer
-Used for drinks cans
-Less dense than iron which makes it lighter
-Used for aeroplanes and bicycle frames
What are the uses and properties of copper?
-Good conductor of heat and electricity
-Used in wiring because of low resistance
-Used in underfloor heating
What are the properties and uses of low carbon steel (0.1%-0.3% carbon)?
-Easily shaped
-Used for car bodies
What are the properties and uses of high carbon steel (0.22%-2.5% carbon)?
-Very strong
-Brittle
-Inflexible
-Used for bridges
What are the properties and uses of stainless steel?
-Corrosion resistant
-Hard
-Used for cutlery
How would you carry out a flame test?
-Clean the nichrome wire in acid
-Dip that wire into a sample and place into a bunsen burner which is on the roaring blue flame
-Observe the colour of the flame
How would you make an insoluble salt - precipitation reaction (lead sulfate)
1) Add 1 spatula of lead nitrate to a test tube and dissolve it in deionised water
2) In a separate test tube add 1 spatula of magnesium sulfate
3)Pour the 2 solutions into a small beaker and stir them together
4) Put a folded piece of filter paper into a filter funnel and stick the funnel into the conical flask
5) Pour the contents of the beaker into the conical flask
6)Ensure all the precipitate from the beaker is removed and rinse the contents of the filter paper to ensure it is only lead sulfate
How would you make soluble salts - using an acid and insoluble base
1) Heat the acid in a water bath in a fume cupboard
2) Add the base to the acid which will produce a soluble salt and water
3)Filter out any excess to get the solution to only contain the salt and water
4) Heat the solution gently using a bunsen burner in order to evaporate out the water
5) Allow the salt to crystalise
How would you make a soluble salt using acid/alkali reactions?
1) Measure out a set amount of acid into a conical flask using a pipette and add a few drops of indicator
2) Slowly add alkali to the acid using a burette until you reach the end point and the solution has been neutralised
3) Then carry out the same reaction using the same volumes of alkali and acid but with no indicator to ensure the salt isn’t contaminated with indicator
4) The solution that remains when the reaction is done is salt and water
5) Slowly evaporate the water and allow the salt to crystalise
