Section 2: Chemistry of the Elements Flashcards
Do metals create acidic or basic oxides?
Basic
Do non-metals create acidic or basic oxides?
Acidic
What are group 1 elements called?
The alkali metals
What happens in terms of properties as you go down the group 1 metals?
1) melting point decreases
2) reactivity increases
Why does reactivity increase down the group 1 metals?
1) more shells
2) electron in outer shell is further away from the pull of the nucleus
3) easier to lose the electron
Describe the reaction of lithium with water
1) floats
2) doesn’t melt
3) doesn’t catch fire
4) creates basic solution (lithium hydroxide)
Describe the reaction of sodium with water
1) floats
2) melts
3) doesn’t catch fire
4) makes basic solution (sodium hydroxide)
what observations can be made during the reaction of potassium and water?
1) effervescence/fizzing/bubbles
2) potassium moves/darts/floats
3) potassium leaves white trail
4) potassium forms into a ball
5) potassium becomes smaller/disappears
6) (lilac) flame
What is chlorine like at room temperature?
A pale green gas
What is bromine like at room temperature?
Orange liquid
What is iodine like at room temperature?
Dark grey solid
What is the trend in physical properties down group 7?
1) melting point increases
2) reactivity decreases
What colour is chlorine when dissolved in water and in hexane?
Water: colourless
Hexane: pale green
What colour is bromine when dissolved in water and in hexane?
Water: orange
Hexane: orange
What colour is iodine when dissolved in water and in hexane?
Water: orange
Hexane: purple
What is the difference between hydrogen chloride gas and hydrochloric acid?
Hydrogen chloride gas is a covalently bonded. When it is dissolved in water it becomes hydrochloric acid and splits into H+ ions and Cl- ions (the H+ ions make it acidic)
Why is hydrogen chloride gas acidic in water but not in methyl benzene?
When hydrogen chloride dissolved in methyl benzene it doesn’t disassociate (split up) so since there are no H+ ions the solution is neutral
What is the trend in reactivity of halogens as the number of shells increases?
Distance between outer shell and nucleus increases
Electrostatic attraction if nucleus and electron it wants to gain is weaker
Harder to gain electrons
Reactivity decreases
If chlorine is added to sodium bromide, will a reaction occur?
Yes, as chlorine is more reactive it will displace the bromide ion
What type of reaction are halogen displacement reactions?
redox reactions
What percentage of air is nitrogen?
78%
What percentage of air is oxygen?
21%
What percentage of air is Argon?
0.9%
What percentage of air is carbon dioxide?
0.04%
How do you prepare oxygen in a lab?
Hydrogen peroxide (+manganese dioxide) —> water + oxygen
What is the chemical equation for the preparation of oxygen in a lab?
2H2O2 —> 2H2O + O2
How do you prepare carbon dioxide in a lab?
Calcium carbonate + hydrochloric acid —> calcium chloride + carbon dioxide + water
what is the reaction of magnesium with oxygen in air?
Oxygen + Magnesium —> Magnesium Oxide (white solid)
what is the reaction of carbon with oxygen in air?
Oxygen + Carbon —> Carbon Dioxide
what is the reaction of sulfur with oxygen in air?
Oxygen + Sulphur —> Sulphur Dioxide
What can you heat to to give carbon dioxide and a metal oxide?
Metal carbonates break down into carbon dioxide and metal oxide in thermal decomposition
Why is carbon dioxide used in carbonating drinks?
Carbon dioxide is soluble in water
Why is carbon dioxide used in fire extinguishers?
Because it is more dense than air so it sinks below lighter gases such as oxygen, covering a fire and keeping oxygen out
What are the products of sulphuric acid and metals reacting?
Metal sulphate and hydrogen gas
What are the products of metal and hydrochloric acid reacting?
Metal chloride and hydrogen gas
How do you test for the presence of water?
Use anhydrous copper sulphate which turns from white to blue in the presence of water
what is the order of metals in the reactivity series?
Potassium Sodium Lithium Calcium Magnesium Aluminium (carbon) Zinc Iron (hydrogen) Copper Silver Gold
Which is the least reactive metal to react with water?
magnesium
Which is the least reactive metal to react with steam?
iron
What is the least reactive metal to react with hydrochloric acid or sulphuric acid?
iron
what is an oxdising agent?
a substance which oxidises something else (provides the oxygen)
what is a reducing agent?
a substance which reduces something else (takes the oxygen)
what is rust?
Hydrated iron (III) oxide
What is the colour of flame in flame test for Li+?
red
What is the colour of flame in flame test for Na+?
orange
What is the colour of flame in flame test for K+?
lilac
What is the colour of flame in flame test for Ca 2+?
brick red
What type of flame is used during flame tests?
Blue/roaring flame so doesn’t interfere with colour reading
How do you test for ammonia?
Add sodium hydroxide solution and warm. It will turn damp red litmus paper blue and smell of ammonia
How do you test for Cu2+ ions?
1) Add sodium hydroxide solution.
2) Forms blue precipitate (copper hydroxide)
How do you test for Fe2+ ions?
1) add sodium hydroxide solution
2) Forms green precipitate
How do you test for Fe3+ ions?
1) add sodium hydroxide solution
2) Forms red/brown precipitate
How do you test for Cl- ions?
Add dilute nitric acid and then silver nitrate solution and then a white precipitate will form (silver chloride)
How do you test for Br- ions?
Add dilute nitric acid and then silver nitrate solution and then a cream precipitate will form
How do you test for I- ions?
Add dilute nitric acid and then silver nitrate solution and then a yellow precipitate will form
How do you test for sulphate ions?
Add dilute hydrochloric acid and then barium chloride and a white precipitate forms (barium sulphate)
How do you test for carbonate ions?
Add dilute acid and then bubbles of carbon dioxide will be produced
How do you test for hydrogen?
Lit splint burns with a squeaky pop
How do you test for oxygen?
Relights a glowing splint
How do you test for carbon dioxide?
Bubble through line water and it will turn milky
How do you test for ammonia gas?
Turns damp red litmus paper blue
How do you test for chlorine gas?
bleaches damp litmus white
What colour would you predict astatine to be?
Black
What colour is fluorine gas?
Pale yellow
what are the conditions required for rusting to occur?
1) oxygen
2) water
what speeds up the process of rusting?
salt
how does a coat of zinc protect iron from rusting?
1) zinc corrodes/oxidises/reacts in preference to
iron
2) because zinc is more reactive than iron
how can carbon dioxide be collected?
1) over water
2) downward delivery in air
3) in a gas syringe
why is potassium more reactive than lithium?
1) potassium loses its outer electron more easily
2) because it is further from the attraction of the nucleus
3) and therefore less strongly attracted
to the nucleus