C2.1-C2.3 Flashcards by Freya Dixon-Brown

What are the three types of bonding?

What types of elements do they occur between?

Sharing, shedding or stealing electrons?

Covalent
non-metal + non-metal
sharing

Ionic
non-metal +metal
stealing

Metallic
metal +metal
shedding

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What is an ion?

A charged particle
-either lost or gained an electron
(protons>electrons or protons

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Are metal ions positively or negatively charged?

What does this mean?

Positively

They’ve lost an electrons
protons>electrons

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What is the relationship between protons and electrons in a positively charged ion?

protons>electrons

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What is the relationship between protons and electrons in a negatively charged ion?

protons

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What happens in an oxidation reaction?

=positively charged

loss of electrons

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What is the relationship between protons and electrons in a particle?

proton=electron

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What happens in an reduction reaction?

-negatively charged

gain of electrons

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What shape do ionic structures make up?

What holds them together?

Lattices

Electrostatic attractions

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What is the process of metallic bonding?

Metal atoms shed their outer electrons
=cat ions (pos.)
cat ions held together w/ delocalised (shed) electrons
=delocalised electron sea 
makes metals strong

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Why do metals conduct electricity?

Electrons can move freely through the delocalised cation sea

When a current is passed through them they move (repelled by other electrons)

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In which direction do vibrating ions pass on heat?

Laterally

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What’s an alloy?

A mixture of two or more metals with different properties to the originals

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Are metals with regimented layers more or less malleable than those with random shapes?

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What are allotropes?

Giant molecules made up of one element arranged in different ways

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Are covalent bonds strong or weak?

Strong

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Why are diamonds so strong?

They have 4 strong covalent bonds between each carbon atom- pyramidal shape

(high melting and boiling points, are hard)

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Why do we use diamonds in jewellery?

They are:
fairly unreactive
hardwearing
attractive

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Describe the structure of graphite

3 strong covalent bonds, 1 weak between each carbon atom- sheets
Small amount of force between layers of atoms

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What are the uses of graphite?

How does it’s structure make it ideal for these uses?

Pencils
layers of atoms can be separated with little force

Lubricant for machinery
layers of atoms can be separated with little force
lower boiling point than oil

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Why can graphite conduct electricity?

There are loose electrons between the sheets of atoms

-currents can be passed through them

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What are the properties of a buckminsterfullerene ball?

What are they used for?

High SA
V small
Hollow

Can be used to carry drugs into the body

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Why do diamonds and graphite have different properties?

structure of diamond:
pyramidal w/ 4 strong covalent bonds between each carbon atom
=strong and hard
poor at conducting electricity:
no delocalised electrons between atoms- no current can pass

structure of graphite:
sheets w/ 3 strong + 1 weak covalent bond between each carbon atom
=layers of atoms separated easily
good at conducting electricity:
delocalised electrons between sheets of atoms- currents can pass

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What is the relationship between the melting point and strength of carbon allotropes?

Higher melting point=stronger

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Do weak inter-molecular forces make it easier or harder to boil a substance?

Easier

What are some examples of polymers and their uses?

LDPE plastic bags HDPE garden furniture PVA glue Neoprene wet suits PET plastic bottles

How is LDPE made? What are it's characteristics? What's the reason for these characteristics?

100-300 c huge pressure initiator (either oxygen or a peroxide) Not strong Low melting point Low boiling point The more branching in the hydrocarbon= the weaker the bonds

How is HDPE made? What are it's characteristics? What's the reason for these characteristics?

300 c low pressure catalyst (aluminium based metal oxide) Strong High melting point High boiling point The less branching in the hydrocarbon= The stronger the bonds (& more inter molecular forces)

What are thermo-softening polymers? What is the reason for this characteristic? What are some examples?

Plastics that always soften on repeated heating Only thing that holds the polymer chains together is the natural attraction of molecules -allows them to separate and melt easily Nylon Polystyrene

What are thermo-setting polymers? What is the reason for this characteristic? What are some examples?

Plastics that remain rigid once set, and that don't soften during heating. They provide thermostability They have cross-linking molecules that form strong covalent bonds, holding the chains together Kitchen appliances

Why are thermo-softening polymers easy to melt?

Their hydrocarbon chains are held together using only weak intermolecular bonds These can be broken easily when heated, as the chains move more with more kinetic energy and break apart

Why are thermo-setting polymers hard to melt?

They have strong cross-links between the hydrocarbon chains These form strong covalent bonds More energy is needed to separate the chains than thermo-softening polymers

How does more branching in a hydrocarbon affect the bonds?

Weakens the bonds

What are protons?

Pos. charged subatomic particles

What is the result when you change the number of electrons in an element?

An ion of the element

What is the result when you change the number of neutrons in an element?

An isotope of the element

What are three isotopes of hydrogen? What is the difference in their neutron number to regular hydrogen?

``` Protium +0 Deuterium +1 Tritium +2 ```

What are deuterium and tritium used for?

The production of nuclear weapons

Do isotopes have the same atomic number to their original element?

YEs

Do isotopes have the same mass number as their original element?

What is RAM (Relative Atomic Mass)?

A unit for measuring masses of atoms (Ar) | - Mass of an atom compared to carbpn

What does RAM compare the mass of an atom to?

1/12 of carbon 12

What is the RAM of carbon?

12 Ar

What is the Ar of an atom?

It's mass number (how heavy it is)

What is the Mr of an atom?

It's relative molecular mass | RFM

How do you find the Mr of a compound?

= the total Ar of all the elements in it

Is Mr for compounds or elements?

Compounds

Is Ar for compounds or elements?

Elements

What is a mole?

A unit (like a chemists dozen) for the amount of substance in an element

Is a mole different for each element?

Yes

What is the equation for finding moles of an element?

mass=moles*Mr

What is mass spectroscopy used for?

Identifying unknown substances

What is the small peak at the end of a mass spectroscopy graph called? What does it show?

The molecular peak The Mr of the compound

What are the two phases of chromatography?

Mobile phase Stattionary phase

What is the mobile phase of chromatography?

The solvent that carries the compound | analogy= water

What is the stationary phase of chromatography?

The solid material that the compound binds to | analogy=rocks

What is the process of chromatography?

Separating a mixture of compounds based on their ability to bind to the stationary phase whilst being carried by the mobile phase

What is percentage mass?

The percentage of an element within a compound | e.g O=53.5% of C6H12O6

How do you find the % mass of an element in a compound?

Find relative formula mass of entire compound Find relative formula mass of element Use the equation: RFM of element/ RFM of compound * 100=% mass

What is empirical formula?

The simplest ratio of different atoms in a compound | need to know mass of each element in compound to work out

What is the reverse process of finding the % mass of a compound from it's formula?

Working out empirical formula

How do you go about finding the empirical formula of a compound?

``` Create table with --> Fill in things you know and work round to calculate the rest Element Grams Mass number (Mr) Moles (Mass/Mr) Ratio (Moles/Smallest number) =Empirical formula ```

How do you find percentage yield?

Actual yield/ Predicted yield X100

Why do very few chemical reactions have a yield of 100%?

Raw materials may not be pure Small amounts of product can be left on apparatus Reaction may not have fully finished Reactants can sometimes give off unexpected products

Define retention time

The time that it takes for for a component in a mixture to travel through the column during gas chromotography

C2.1-C2.3 Flashcards

(65 cards)