Flashcards in My Cards 2 Deck (26):
What is shape memory metals
It can remember it's original shape if broken or deformed
What is Thermosoftening polymers
Individual tangled chains of polymers held by weak intermolecular forces and slide over each other.
They don't have cross links between chains so the forces between the chains are easy to overcome and easy to melt. You can melt and remould as many times as you like
What is thermosetting polymers
These have strong intermolecular forces between polymer chains called crosslinks which hold the chains firmly together. It doesn't soften when heated. They are strong hard and rigid
What is the advantage of nanotechnology
Get into the body easier in delivering drugs or suncream.
Very very small.
Don't know what long term impact as it is very recent.
What are isotopes
Different version of the same element
How do u work out a relative formula mass
Multiply the amount of atoms you have by the elements weight
What is Ar
Relative atomic mass
What is Mr
Relative mass formula
To find the percentage of and atoms in the Ar you..
divide the Ar of that atom and divide it by the Ar of the full equation then multiply by 100
How do u work out empirical formula
List the elements in their experimental masses. Then divide my the atomic mass of each element. Turn the numbers you get into a ratio by multiplying and/or dividing them by well chosen numbers(e.g 0.8 multiplied to 8). Get the number into its simplest form and then it tells you the empirical forumla. Answer e.g = Fe203 (empirical formual is the 2 and the 3)
How do u calculate percentage of mass of an element in a compound
Ar X number or atoms of that element
Mr of the whole compound
What is yield
The useful product given from a reaction
How do you work out the percentage of yield?
Actual yield (grams)
Can you ever get 100% of yield ?
No! Some product or reactant will get lost along the way
What is the reason for the maximum amount of yield produced?
Because it was a reversible reaction. This means the products of a reaction can react themselves to produce original reactants
(E.g ammonium chloride ammonia+hydrogen chloride
Why do we use chromatography
To separate out substances
How do You produce a chromatography experiment
Place food colour either mixture
Or one dye out on chromatography paper but draw a pencil line to put spots on. Hang it over a beaker with solvent in making sure the pencil line is above the solvent . The solvent seeps up that paper taking dyes with it and makes different dyes form in different places on the paper.
What are advantages of machines analysing unknown substances
How is gas chromatography
A sample enters the oven. Lower down the line a gas is entered to carry the substance around. The substances travel through the tube at different speeds so they separate out.
What does the rate of reaction depend on
Surface area of solids
How do you measure the rate of reaction
Amount of reactant used up or amount of product formed
What are the 3 ways to measure
Rate of reaction
Precipitation (when product clouds in solution)
Change in mass (usually gas given off)
Volume of gas given off (using gas syringe)
Increase the rate of reaction. This is because higher temperature increases collisions as particles move quicker. Higher concentration (or pressure) increases collisions as there is more particles to collide with. Larger surface area increase collisions so there is more area to work on.
What are the 3 broken down reasons for collision theory
1) higher temperature
2) higher concentration or pressure
3) larger surface area
What does a catalyst do
Speeds up a reaction without be changed or used up