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Chemistry Mine > C1 > Flashcards

C1 Flashcards

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1
Q

What is a particle?

Atom

A

A tiny bit of matter

Smallest particle of an element that still has its chemical properties

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2
Q

Particle model for each

What does particle model show

Lomtieruojs

A

Solid

  • regular arrangement
  • very Close distance between particles
  • vibrate fixed positions (fixed so dan’t flow over ach other)

Liquid

  • random arrangement
  • still relatively close distance between particles (therefore can’t compress
  • move around each other (flow) ( this means they can occupy any volume they go into)

Gas

  • random arrangement
  • particles far away from each them (can compress)
  • particles move qucky in random directions

1) doesn’t show the space between,
2) actual size of lsrtickes
2) forced
4) psrtciels aren’t just spheres

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3
Q

What is a formulation

Physical chemical

A

A mixture that has been designed to be useful eg fertilster, washing product but not water.

Chemical change is nit easily revesible , diffuclyt , sunayxne msde, propertied diffeeende, neutralisation

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4
Q

Apparently for covalent?

How do atoms react

A

Atoms react to gain the same electron configuration as the nearest noble gas

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5
Q

Why are metals good conductors in heat?

A

Metals are good conductors of heat because the delocalised electrons allow thermal energy to be transferred easily through the substance.

5

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6
Q

What is characteristic of low density poly ether (lode)

A

Polymers are branched, meaning they are arranged randomly therefore allowing them to be weak and flexible.

This makes them ideal for bags and bubble wrap
L

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7
Q

During which change do particles lose energy to the surroundings?

A

H

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8
Q

Why do some people have concerns about the use of nanoparticles in sunscreens?

A

There is some concern that nanoparticles used in sunscreen and other cosmetics could enter the bloodstream with unpredictable results. More research and longer-term studies are needed.

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9
Q

When do we use “di” as prefix

A

The name of the chemical compound MgF2 is magnesium fluoride. We only use “di” in covalently bonded compounds.

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10
Q

Strong acids

A

Fully dissociates into ions when dissolved in water and the change is not reversible

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11
Q

Electrolysis of aqueous salts

A

The thing that is least reactive is produced at cathode and reactivity series, and more reactive in na7oncs…

In reactivity series, copper last c
Calling = calcium first c (ca for both)
CARELESS NOW= Carbon (car)

Platinum at end
Please stop calling me a careless zebra I think love has come so god please

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12
Q

LEARN ELECTROPLATING

A

E

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13
Q

Which halogen is a liquid at room temperature?

A

Brominw

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14
Q

What ,ade Statue of Liberty like it is

A

CuO?

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15
Q

What are limitations if the particle model?

A

The particle model does not take into account

  • the size of each particle
  • the forces between them
  • the space between particles x too big to show

Doesn’t show forces in gas, distance, size are all the same…

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16
Q

Atom molecule element

Bond length

A

Atom smallest particle of an ale meant
Element made out if one atom
Molecule made out of two or more

Bind length is 2 radii

17
Q

Briefly summaries Dalton and Mandem

A

1) first dalton. Who suggested wllmmstternis made from stokes, and that atoms of an element are the same, different elements different atoms. Saw them is small indestructible balls.

2) Next Thompson , who worked out cathode rays were negatively charged through magnetic fields and did experiments with the,. From this he saw the cathode rays must be coming fork inside the atom, therefore the atom was described to have negative electrons dotted around the atom, and a ball of psoorve mass to Dougherty the charge
- he said charge if atom is and TEHY CONSTAIN ELECTORNS.Z

2)rutherford, mares en and Geiger,
Tried to prove the plum pudding model. They worked out sohos particles with positively charged using electric fields, and decided to fire them at gold foil .
- expected it to go straight through as change was considered to be evenly spread around the atom. While most did come through, SOME CHANGED DRIECRJON, SND SOME CAME BACK 90.
- this showed that since msotnwent htiugh, it was empty space
But since some came back, there was a positive mass in the middle, nucleus that was reflecting them.
2 said electrons orbit outside like a SOLAR SYSTEM

4) Bohr used mathematical experiments . He knew that according to Rutherford eventuakkybthe electrons would spiral in and collide with the atoms. He improved and said electrons sit in fixed energy levels around the electron at fixed distance .

18
Q

Remember formula mass / molar difference with atomic?

A

Atomic for one molecule, formula for all

Molar mass misleading ?

19
Q

Pure

How to see it pure

A

Substance containing one element of one compound

Pure substance will have a certain boiling and melting point. If a substance being tested melts over a range of temperatures, or at the wrong temp, then its’ not pure

20
Q

Alloy?

A

A metal mixed with one or MORE ELEMENTS, makes it more useful

21
Q

How to see melting point (practical key bits)

A

1) MUST STIR THE LIQUID MAINTING A CONSYANT TEMO
2) heat it slowly so it even improve accuracy
When temo stops rising that’s melting point

22
Q

Sollte solvent solution difference

A

Solute is alt
Solvent water
Solution both

23
Q

Filtration

A

Uses to separate a insoluble solid (sand) from liquid (water)

Use filter paper, as this has holes small enough. Residue (sand) stays, filtrate (water ) goes through. Makes sure to to FLUTE A FILTER PAPER ( HELLA FOLD)

24
Q

Crystallisation or (distillation)

A

Separates the solute from solvent, distillation separates the solvent from solute, but both similar,

Chrstallation:

1) pour solution in evaporating dish, gently hets it up, HAS RO BE GENTLE or won’t work. Some of the solvent evaporates making it more concentrated.
2) once it reaches saturation (where adding more salt won’t dissolve because less water now), remove the what and let it fool down. As it cools, solubility will decrease and crystals begin to form
3) bigger crystals mean gentler heat
4) filter the rest out to just get crystals then a DRY

25
Q

Distillation .

Why fractional used ? Other word why simple bad?

A

Distillation separates a solvent from solution. ONLY WORKS BECAUSE THE SOLVENT (water) Has lower boiling then solute (salt) or else no. Requires to heat solution, then the water will evaporate.

2) it enters condenser, where (remember ) cooling water out is at the entrance of valider, cooling water in is where water leaves. This happens so the gas is fully condensed by then. Gravity there too so water falls in. As it makes through condenser gets colder due to water na dcondenses, leaving solute behind…

Good for lab

Not good for mixtures with SIMILAR BOILING POINTS.

26
Q

Fractional distillation?

A

This uses similar concept, but a fractionating column. It departed two or more substances in LIAUID STATE, but they need different boiling points, and you should know.

2) heat it. Heat makes a temperature gradient across the column, colder at top, hotter st bottom.
3) therefore when the lower boiling point evaporates, it will keep condensing until it goes to the top where the Tempe there is also = to its boiling point. Whatever happens first will make way ti condenser, cooled and condensed and collected.
The other boiling point hasn’t been reached yet, for example water more then ethanol. This keeps condemning every time it evesporstes , snd stays in the original flask…

You could just let the ethanol go, then do water …. and others

27
Q

Chromatography TLC, and paper

Why use a watch glass bruh

A

Chronatorgraphy is used to separate different substances in a mixture, and identify them…

Uses two phases- stationary and mobile, mobile it can move, stationary ti can’t

Paper = mobile water, stationary paper

TLC

1) mobile phase is solvent like water, stationary is Alumina powder or silica
2) (WATCH GLASS STOP SOLVENT EVAPORATE)draw line 1 cm from end. Apply substance here. Important pencils is used as they are insoluble ). Spot csn’t be pencil line can’t be under water, or the specimen will dissolve in the water ruining everything.
3) as the solvent moves up the plate, the substances in the mixture will bind to the mobile phase and stationary phase . Those that bind more with mobile are more soluble= END UP HIGHER ON THE PLATE. Those that firm STRINGER (key wird ) bonds with stationary phase will not travel as far…

28
Q

What is Rf and how calculate what does it tell you?

How tell if pure.

A

Rf is the ratio between distance traveled by substance /solvent. Always be less then 1. Each pure sample will always be the same Rf, so you can compare them

If substance pure, only one blob, no more…

29
Q

Gas chromatography?
IMPORTWNT FAVTSBYIU GOT WRONG IN TEST!

Area? Pure?

A

Also used to separate substances and identify them

Stationary phase still ALUMINA OR SILICA POWDER but packed into the metal column

Mobile phase this time UNREAVTIVE carrier gas like nitorgen thsy does not rest with any of the samples

1) sample turned into gas state injected into the colour
2) carrier gas pushes them through column, and this at different speeds depending how strong they form binds with stationary phase.
3) they come out at the end and a detector sends a signal as each time it Leaves
4) completed produces a chromatogram where each peak is a different substance, also, against the time it takes to move across which is called RETENTION TIME.

1) Retention time different for each substance and that tells you what it is by comparing them
2) area shows you RELATIVE AMOUNT OF EACH
3) if pure then one substance

30
Q

Why may there be more substances in a sample then a chormotagram shows?

2

A
  • SOME PEAKS MAY BE HIDDEN / under or merged with another peak
  • the retention times are very similar and so two substance on top of each other…
31
Q

Phosphate is?

A

Po4 -3.

Chemistry Mine (13 decks)

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