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Flashcards in My Cards 2 Deck (26):
1

What is shape memory metals

It can remember it's original shape if broken or deformed

2

What is Thermosoftening polymers

WEAK FORCES
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

3

What is thermosetting polymers

STRONG FORCES
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

4

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.

5

What are isotopes

Different version of the same element

6

How do u work out a relative formula mass

Multiply the amount of atoms you have by the elements weight

7

What is Ar

Relative atomic mass

8

What is Mr

Relative mass formula

9

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

10

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)

11

How do u calculate percentage of mass of an element in a compound

Ar X number or atoms of that element
---------------------------- X100
Mr of the whole compound

12

What is yield

The useful product given from a reaction

13

How do you work out the percentage of yield?

Actual yield (grams)
-------------
Predicted yield(grams)

14

Can you ever get 100% of yield ?

No! Some product or reactant will get lost along the way

15

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

----->

16

Why do we use chromatography

To separate out substances

17

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.

18

What are advantages of machines analysing unknown substances

Very sensitive
Very fast
Very accurate

19

How is gas chromatography
Taken place?

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.

20

What does the rate of reaction depend on

Temperature
Concentration
Catalyst
Surface area of solids

21

How do you measure the rate of reaction

Amount of reactant used up or amount of product formed
---------------------------------
Time

22

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)

23

More collisions....

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.

24

What are the 3 broken down reasons for collision theory

1) higher temperature
2) higher concentration or pressure
3) larger surface area

25

What does a catalyst do

Speeds up a reaction without be changed or used up

26

In industrial reactions what do catalyst's do?

Reduce costs.