Chemistry 1 - a Flashcards
What does the structure of a nucleus look like?
Nucleus in the middle
Nucleus is made from protons and neutrons
Electrons in outer shell move around nucleus
Shells hold 2,8,8,10 electrons
Properties of Protons, Neutrons and Electrons
Protons = positive - 1 Neurons = neutral - 1 Electrons = negative - 1/2000
What is an element?
Elements consist of only one type of atom
What are the mass and atomic numbers?
Mass number is top = no of protons and neutrons
Atomic number is bottom = no of protons/electrons
What is a compound?
Different atoms that have reacted and formed chemical bonds with each other. Made through ionic, covalent or metallic bonding.
What is ionic bonding?
When a metal and a non-metal gain/loose electrons to get a full outer shell. Metals loose electrons to form positive ions - non metals gain electrons to form negative ions.
What is covalent bonding?
When two non-metals share electrons with each other to get a full our shell.
What is limestone?
Calcium Carbonate
CaCO3
What does limestone make when it is thermally decomposed?
Calcium oxide and carbon dioxide.
CaO + CO2
What is thermal decomposition?
When a substance is chemically changed into at least 2 new substances when heated.
What happens to calcium carbonate when it reacts with an acid?
It makes a calcium salt, carbon dioxide and water.
What is made when calcium oxide is mixed with water?
Calcium hydroxide
What do we use calcium hydroxide for?
In water it is limewater and can be used to test for carbon dioxide. If you bubble gas through it and it turns cloudy theres CO2 in it.
How is cement, mortar and concrete made?
Cement - powdered limestone in a kiln with powdered clay
Mortar - Cement + sand and water
Concrete - Cement + sand + aggregate
What are the bad things about quarrying limestone?
^ Creates huge, ugly holes that permentantly change the landscape
^ Noise and dust pollution
^ Destroys habitats
^ Extra transports in area means more pollution and traffic
^ Waste materials create ugly tips.
^ People can have breathing problems
^ Fossil fuels are burnt in process
What are the good things about quarrying limestone?
^ Provides us with houses and roads, dyes, paints and medicines.
^ Limestone neurtalises acidic soil.
^ Neutralises sulfur dioxide in chimmneys
^ Provides jobs
^ Boosts local economy and businesses.
^ After quarrying they usually restore the landscape as much as possible.
Advantages and disadvantages of limestone products?
^ Widely available and cheaper than granite or marble. ^ Hard-wearing but looks attractive ^ Wont rot and can't be eat by animals ^Fire resistant ^ Doesn't corrode
But
Concrete looks very unattractive
What is an ore?
A rock which contains enough metal it is economically worthwhile to extract from.
Why can the economics (profit) of metal extraction change over time?
^ Market price drops
^Prices increase so its not worthwhile to extract
^ With improved technology you can extract metal that before was not worthwhile
How are metals extracted from ores?
Reduction - chemically (with carbon )
Electrolysis - splitting with electricity
What happens when an ore is reduced?
Oxygen is removed to leave the element on its own.
When will reduction work?
Metals higher than carbon must be extracted with electrolysis
Below carbon then they can be reduced in a blast furnace with carbon. As carbon will only take oxygen from those that are lower in the reactivity series.
