Inorganic chemistry Flashcards
What are the 4 gases in the atmosphere?
nitrogen, carbon dioxide, oxygen argon
What % of argon is in the air?
nearly 1%
What % of nitrogen is in the air?
78%
What % of oxygen is in the air?
21%
What % of CO2 is in the air?
0.04%
What two things can be used to measure the oxygen in the air and why?
iron, iron reacts with oxygen in the air to form rust, so will remove oxygen from air
phosphorous
what is the formula for calculating volume?
start volume - final volume / start volume X100
How do you determine the amount of oxygen with phosphorous?
- place in tube and attach two gas syringes to each side
- one syringe should be filled with air one not
- heat, pushing the air between both syringes
- as reacts air will decrease
- measure start and final volume of gas
- use formula
How do you calculate the amount of oxygen in the air with iron?
- soak iron wool with acetic acid
- push wool into measuring cylinder and invert it and place in water beaker
- record starting position on measuring cylinder
- overtime water will rise as iron reacts to form iron oxide
- leave water cylinder until water stops changing and record final value
- use formula
What is formed when an element is burned in the air?
reacts to form an oxide
Explain how magnesium reacts with oxygen?
bright white flame, white powder formed
Explain how hydrogen reacts with air?
very easily, orange/yellow flame
Explain how sulfur reacts with air?
pale blue falme
What does the thermal decomposition of metal carbonates produce?
CO2 and metal oxide
What colour and substance is copper carbonate?
green powder
What will copper carbonate decompose to form?
copper oxide and CO2
Explain how to do a thermal decomposition experiment?
place copper carbonate in a test tube with bung horizontally and heat this part, coming gout of that test time is a tube connected to another test tube which collects the CO2 gas
What is the temperature of the earth a balance between?
heat it gets from sun and heat it radiates into space
`what do gases in the atmosphere act like for the earth?
an insulating layer
What do green house gases do?
absorb most of the heat that would-be radiated into space and reradiate it in all directions back to earth
how are humans effects CO2 levels?
- deforestation
- burning fossil fuels
What is increasing CO2 linked to?
climate change
what is climate change?
earths temperatures increasing
What other global warming does climate change cause?
change to rainfall, flooding
metal + acid =
salt + hydrogen
What do how metals react with acids tell you?
their reactivity
How can you tell the reactivity of a metal by using acids?
the more reactive the metal, the faster the reaction
Explain a practical to investigate the difference in reactivities of different metals?
- fill up 3 boiling tubes and add the same amount of acid to all
- place pieces of magnesium, iron and zinc in different ones
- ## speed of reaction is indicated by the rate at which hydrogen bubbles are given off
metal + water =
metal hydroxide + hydrogen
Which metals will react vigorously with water?
potassium, lithium, sodium, calcium
what will less reactive metals react with?
steam
less reactive metal + steam =
metal oxide + hydrogen
give examples of less reactive metals?
magnesium zinc and iron
Give the reactivity series?
most reactive to least
Potassium sodium lithium calcium magnesium aluminium zinc iron copper silver gold
What is iron used for?
building construction, car manufacture, garden furniture
What is the problem with iron ?
it rusts or corrodes easily
When does rusting happen?
when iron is in direct contact with water and oxygen
What type of reaction is iron corroding?
oxidation
What is the word equation for iron rusting?
iron + oxygen + water —-> hydrated iron (III) oxide
What are the two main ways to prevent rusting?
barrier methods
sacrificial methods
What are the barrier methods?
painting or coating with plastic
oiling or greasing - moving parts
What is the sacrificial methods?
placing a more reactive metal with the iron so that it rusts instead of iron
zinc is often used - sprayed on ( galvanising) or used as a metal block- used on hulls
What is oxidation?
loss of electrons
What is reduction?
gain of electrons
What is an oxidising agent?
substance that is reduced - gains electrons
What is a reducing agent?
substance that gets oxidised - looses electrons
What are metal ores?
metal that has reacted with other elements to form a compound that is worthwhile extracting
Why are metal ores protected?
they are a finite resource and limited amounts
If a metal is very reactive the….
harder it is to extract from compound
How can the metal be separated from from its oxide?
reduction reaction
What is the most common reduction reaction for metal ores?
uses carbon as a reducing agent - heating the ore with carbon monoxide
What is the problem with using carbon to extract metals?
only metals that are less reactive then it can be extracted
What types of ores do very reactive metals form?
very stable ores
What can you use to extract when the metal is more reactive then carbon?
electrolysis