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Science 2017 > Matter And Materials > Flashcards

Matter And Materials Flashcards

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1
Q

What can materials be classified into

A

Pure substances and impure substance

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2
Q

What can impure substances be classified into

A

Homogeneous mixtures and heterogenous mixtures

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3
Q

What can pure substances be classified into

A

Elements and compounds

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4
Q

What can elements be classifieds into

A

Metals and non metals

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5
Q

Where are metals found on the periodic table

A

On the left side

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6
Q

Where are non metals found on the periodic table

A

On the right side

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7
Q

what are the metals in group one called

A

Alkali metals

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8
Q

What are the metals in group 2 called

A

Alkali earth metals

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9
Q

what are the group 17 element

A

Halogen

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10
Q

What are the group 18 elements

A

Noble gasses

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11
Q

What are some properties of non metals

A

They are dull, brittle, not sonorous, heat and electrical insulators

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12
Q

What are some qualities of metals

A

Have lustre, are brittle, are ductile, are sonorous, are heat and electrical conductors

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13
Q

What are electrical cables usually made out of

A

Copper because it is a good electrical conductor and is relatively inexpensive

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14
Q

What are copper wires usually covered with

A

plastic because plastic is an insulator

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15
Q

What are heater and stove elements made out of

A

Nichrome wire because it has high resistance and as a result heat is generated when a electrical current flows through it.

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16
Q

What are cooking pots made out of

A

Metal because metal is a good conductor of heat. The handles of pots are made out of plastic or other non-metals because they are thermal insulators

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17
Q

what are winter clothes made out of

A

Thick fabrics which trap air. Air is a thermal insulator, which helps maintain body temperature.

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18
Q

What are magnetic metals called

A

Ferromagnetic

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19
Q

What are the three magnetic metals

A

Iron, cobalt and nickel

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20
Q

What are magnets used fo in real life

A

Electric motors, speakers and compasses

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21
Q

What are semi metals or metalloids

A

They are elements that have properties of both metals and non metals

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22
Q

What are the 8 metalloids

A

Boron, silicon, germanium, arsenic , antimony, tellurium, polonium and astatine

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23
Q

Do most metalloids behave like metals or non metals

A

Non metals

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24
Q

How do metalloids act like non metals

A

They are brittle

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25
Q

How do metalloids act like metals

A

They are good conductors of electricity, but not as good as metals

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26
Q

What is an interesting property of metalloids

A

They conduct electricity better at higher temperature

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27
Q

What are metalloids used in

A

In microchips

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28
Q

What metalloids are used in microchips

A

Silicon and germanium.

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29
Q

When is a compound formed

A

When two or more elements combine chemically in a fixed ratio

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30
Q

What is a mixture

A

A combination of two or more substances in which each substance retains their individual properties

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31
Q

What are the two types of mixture

A

Homogenous and heterogenous

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32
Q

What is a homogenous mixture

A

A mixture in which the composition is the same throughout and consists of two or more substances in the same phase

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33
Q

What is axis a mixture of and what type of mixture is it

A

Nitrogen, oxygen and small amounts of carbon dioxide. It is a homogenous mixture

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34
Q

What is saline

A

A homogeneous mixture of water and solid salt

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35
Q

What is a metal alloy

A

A homogenous mixture of one solid dissolved in another solid

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36
Q

What is an sample of a metal alloy

A

White gold

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37
Q

What is white gold a mixture of

A

Gold, palladium, nickel and traces of other metals

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38
Q

What is a heterogenous mixture

A

A mixture in which the composition is not uniform. You can see the different substances. Any combination of substances that do not dissolve in one another is a heterogenous mixture

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39
Q

What will happen when sand is mixed with water

A

It will form a suspension. Sand particles do not dissolve in water if left to stand the sand will sink to the bottom

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40
Q

What is it called when two liquids do not mix

A

They are said to be immiscible

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41
Q

what is an example of an immiscible mixture

A

Oil and water

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42
Q

What is an example of emulsion

A

When a mixture of oil and water is shaken and the oil separates into tidy droplets which disperse throughout the water

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43
Q

What can be added to emulsions to prevent them from separating

A

Emulsifiers

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44
Q

What is mayonnaise

A

An emulsion of egg yolk and oil

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45
Q

How can mixtures be separated

A

By physical means

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46
Q

How can a salt water solution be separated by physical means

A

Through evaporation and condensation

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47
Q

How can oil and water be separated

A

By using a separating funnel

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48
Q

How can iron filings and sand be separated by physical means

A

By a magnet

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49
Q

How can water and sand by separated by physical means

A

Filtration

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50
Q

How can the purity of a substance be checked

A

By using boiling and melting points

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51
Q

How can purity be checked by using boiling and melting points. Eg. Alcohol and water

A

Looks like a pure mixture, but can test if it is by seeing if it boils at 100˚c or less. If it is less, the substance is not pure water.

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52
Q

What is another way of checking purity

A

A process called chromatography

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53
Q

What is chromatography

A

It is when the substance being tested is dissolved in a liquid such as water. The solution is then passed through another material, such as paper. If the substance is not pure, the different parts travel through the paper at different speeds and are separated

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54
Q

Who was Robert brown

A

A botanist studying pollen grains suspended in water under a microscope.

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55
Q

What did Robert Brown discover

A

That minute particles ejected by the pollen were moving around in a random jittery motion.

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56
Q

What is this random motion of the small particles ejected by the pollen grains called

A

Brownian motion

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57
Q

How did scientists explain this motion

A

They explained this motion by assuming that all matter is made out of tiny particle, which they called atoms, which are constantly moving

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58
Q

What happens when ink is dropped in water

A

The ink slowly diffuses into the water, this is done by the movement of the water particles

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59
Q

What determines properties of material

A

The way the atoms are bonded to one another

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60
Q

What properties does the bonding of atoms determine

A

Whether a substance is solid, liquid or gas at room temperature

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61
Q

What are the properties of a solid

A

The particles vibrate in place, strong forces hold the atoms together in a crystal lattice, has its own shape and volume and the particles are close together and not compressible

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62
Q

What are the properties of a liquid

A

Forces still hold particles together but are weaker than the forces between particles in a solid. particles are able to change place and are therefore able to move over one another and can be poured. It takes on the shape of its container, but has its own volume and the particles are close together and not compressible

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63
Q

What are the properties of a gas

A

Forces between particle are almost non-existent. Particles are free to move and thus fill the whole container. Has no shape, fills container, fills container, has volume of container. Particles are far apart and are compressible.

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64
Q

What does it mean if all particles are moving but boot at the same speed.

A

It means that some particles have higher kinetic energy and some have lower kinetic energy

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65
Q

What is temperature

A

It is proportional to the average kinetic energy of an objects particles

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66
Q

What happens when the temperature of a substance changes

A

Substances may change phase

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67
Q

What is the melting point

A

The point at which a solid changes to a liquid

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68
Q

What is the freezing point

A

The point at which a liquid becomes a solid

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69
Q

What is the boiling point

A

The point at which a liquid becomes a gas or a gas becomes a liquid

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70
Q

What is evaporation

A

Not all particles have the same kinetic energy and there are strong forces between the particles. The particles at the top may have more kinetic energy and are able to overcome the force of attraction and escape from the liquid forming a vapour

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71
Q

What happens to the remaining particles once the top layer of the liquid has evaporated

A

They have less kinetic energy cause the temperature of the remaining liquid to drop. This is used to regulate body temperature

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72
Q

How is evaporation used to regulate body temperature

A

When we are hot, we sweat, when the sweat evaporates, it cools our body’s down.

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73
Q

What are the similarities between evaporation and boiling

A

They both result in a phase change from liquid to a vapour

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74
Q

What are the differences between evaporation and boiling

A
  1. evaporation takes place at any temperature, boiling takes place at specific temperature.
  2. Evaporation takes place at the surface only, boiling occurs throughout the liquid
  3. Boiling takes place when the pressure of the vapour in the bubbles is equal to the atmospheric pressure
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75
Q

What is the relationship between forces and boiling point

A

The stronger the forces between the particles in a substance are, the higher the boiling point. The weaker the forces between the particles in a substance are, the lower the boiling point. This is because the stronger the forces, the more energy is required to break the bonds between the particles.

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76
Q

What happens when a liquid is boiling

A

There are bubbles of vapour that form during this process that rise to the top and release their vapour.

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77
Q

How does atmospheric pressure affect boiling point

A

The boiling point is determined by the atmospheric pressure because a substance will only boil when the pressure in the bubbles in the liquid are the same as the atmospheric pressure. They are directly proportional, the higher the atmospheric pressure, the higher the temperature needs to be for a substance to boil.

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78
Q

What is sublimation

A

When a substance changes directly from a solid to a gas

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79
Q

What is an example of sublimation

A

When Iodine crystals are heated, they do not become a liquid by immediately form iodine gas

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80
Q

What happens when a solid is heated

A

The particle start to vibrate more, thus increasing their kinetic energy, and the bonds between them start to break. The particles also have forces of attraction, and if very close together, they also have forces of repulsion. So in addition to increased kinetic energy, they also have increased potential energy

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81
Q

What happens when a solid is heated to its melting point

A

The heat does not increase their kinetic energy, but their potential energy. At this temperature the rigid structure of the crystal lattice starts to break apart into the liquid phase only once al the molecules have broken free can they start to gain kinetic energy and the liquid’s temperature starts to rise

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82
Q

What happens when a liquid is heated to its boiling point

A

The temperature remains constant until all the liquids have been changed into vapours. the heat is converted into potential energy

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83
Q

Why is boiling a substance often more difficult that melting a substance

A

Because during the boiling, the bonds of the substance have to actually break, whereas when it is melting, they just gain more kinetic and potential energy

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84
Q

What is the current model of the atom

A

There is a nucleus in the centre of an atom, it consists of protons and neutrons. Electrons orbit around the nucleus

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85
Q

What is the atomic number

A

The number of protons in an atom. It determines what element it is going to be.

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86
Q

What is the atomic mass of an atom

A

This is the nucleus because the nucleus is the mass of the atom thus the atomic mass is the protons plus the neutrons

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87
Q

What is an isotope

A

Atoms of the same element which have different mass numbers. They have the same number of protons, but different number of neutrons

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88
Q

What are the isotopes of chlorine

A

Chlorine 35 and chlorine 37

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89
Q

What is a cation

A

A positively charged ion

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90
Q

What is an anion

A

A negatively charged ion

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91
Q

What is an ion

A

A charged atom

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92
Q

When is an atom positive

A

When it has lost electrons

93
Q

When is an atom negative

A

When it has gained electrons

94
Q

What do the names of negative ions usually end with

A

-ide

95
Q

What two assumptions did Bohr make

A
  1. That electrons can only move in fixed, permitted orbits
  2. That the electron moving that fixed orbit had a definite energy which could not change while the electron was moving in the specific orbit
96
Q

What are the fixed energies that electrons in an atom can have called

A

Energy levels

97
Q

what can an electron not do while travelling in an energy level

A

They can not emit energy or absorb energy

98
Q

How can electrons radiate energy

A

The electron has to fall from a high energy level to a lower one

99
Q

How do electrons absorb energy

A

It has to jump to higher energy levels

100
Q

What is quantised energy

A

The energy radiated or absorbed by electrons. It is limited to certain energy values determined by the energy differences between the energy levels

101
Q

What does the atomic model take into consideration

A

The wave nature of electrons, which is provided by the fact that streams of electrons produce diffraction patterns

102
Q

What is it possible to calculate in an atom

A

The energy, the shape and most likely the position of an electron wave

103
Q

What are orbitals

A

The regions where electron waves are most likely to be found.

104
Q

What are the two orbitals

A

S-orbital

P-orbital

105
Q

What is the s-orbital

A

It is spherical and they are arranged symmetrically around the nucleus, but differ in size.

106
Q

How many a-orbitals are there in every energy level

A

Only one

107
Q

A maximum of how many electrons can be found in the s-orbital

A

2

108
Q

The maximum number of electrons that the p-orbital can hold is

A

6, two in each part of the p-orbital

109
Q

What is the p-orbital

A

It is shaped like an infinity sign and comes in groups of 3. They are found in the second energy level onwards. They can hold a total of 6 electrons

110
Q

What are valance electrons

A

Electrons found on in the putter most energy level. It is he same as the group numbers

111
Q

What are the core electrons

A

They are the electrons found in the inner most energy level

112
Q

What is the s-block

A

Groups one and two, this means that the elements found in these groups have their outermost electrons in an s-orbital

113
Q

What is the p-block

A

Groups 13 to 18 this means that the elements found in these groups will have their valance electrons in a p-orbital

114
Q

Groups

A

Vertical columns
Elements in a group have similar chemical properties
Group numbers enables the charge of an ion to be found

115
Q

Periods

A

Horizontal rows
One atom differs from the neighbouring atom by one proton
Period number is = to the number of the outermost energy level

116
Q

Metals

A

Are found on the left side
Generally have few valance electrons
Generally lose electrons easily, so they for a positive ion

117
Q

Non-metals

A

Right side
Late number of valance electrons
Accept additional electrons, so they form negative ions

118
Q

Noble gasses

A

In group 18. They are extremely stable because their outermost energy level is completely full, so they do not bond with other substances

119
Q

What determines the reactivity of a substance

A

The presence of unpaired electrons

120
Q

What happens to atoms during a chemical reaction

A

They often gain or lose atoms to gain noble gas status.

121
Q

What are the gradually changing properties of the elements in a given period on a periodic table associate with

A

With gradually changing valance electron configuration

122
Q

What is the atomic radius

A

It is the radius of an atom, from the nucleus to the outermost electrons.

123
Q

How does the atomic radius change on the periodic table

A

It decreases from left to right and increases from top to bottom

124
Q

Why does the atomic radius decrease from left to right

A

Because the forces of attraction between the nucleus and the electrons increases, cause long the atom to become more compressed

125
Q

Why does atomic radius increase from top to bottom

A

Extra energy levels

126
Q

What is atomic density

A

The mass per unit volume. This means that it is the size of the atom as well as the in which they are packed together.

127
Q

Which atoms are more dense

A

Non-metals because their atoms are not packs as tightly together.

128
Q

In metals, how does density increase/decrease on the periodic table

A

From left to right increases

Top to bottom increases

129
Q

Why does density increase from left to right

A

Atomic radius decreases and atomic mass increases

130
Q

Why does density increase from top to bottom

A

Atomic radius increases, atomic mass increases

131
Q

What is ionisation energy

A

The energy required to remove an electron from a single atom in the gaseous phase

132
Q

How does ionisation energy increase/decrease on the periodic table

A

It increases from left to right

It decreases from top to bottom

133
Q

What is electron affinity

A

The energy liberated when an electron is added to an atom in the gaseous phase

134
Q

How does electron affinity increase/decrease on the periodic table

A

It increases from left to right

It decreases from top to bottom

135
Q

What is electronegativity

A

It is an indictaion of the attractive force which an atom exerts on a shared electron pair

136
Q

What is the most electronegative element

A

Florine

137
Q

How does electronegativity increase /decrease on the periodic table

A

The same wa as electron affinity

138
Q

What are the properties of the alkali metals

A

Most reactive because they have only one valance electron. Not found in their elementary form in nature, but in compounds. Once the elements have been extracted, they have to be stored in an inert liquid so that they do not react. They all react with cold water to produce hydrogen and a hydroxide. They are all soft and light gray.

139
Q

What are the properties of the alkali earth metals

A

They are also very reactive because they only have 2 valance electrons. They all react with cold water, except for beryllium, to produce hydrogen and a hydroxide. All, apart from beryllium, are light grey, relatively soft and are good conductors of heat and electricity

140
Q

What’s re the properties of the halogens

A

They are very reactive because they have 7 valance electrons. All have relatively low melting points. At room temperature, Florine and chlorine are gases, bromine is a liquid and iodine and astatine are solids

141
Q

What are the properties of the noble gases

A

They are exceptionally unreactive. They are gases at room temperature

142
Q

What is the bond between two metals called

A

A metallic bond

143
Q

What is the bond between two nonmetals called

A

A covalent bond

144
Q

What is the bond between a metal and a nonmetal called

A

An ionic bond

145
Q

Ionic bond

A

A transfer of electrons
One is an electron accepter(forms a negative ion) and one is an electron donor (forms a positive ion)
Ions pack in an ionic crystal lattice

146
Q

What are two important exceptions on the periodic table

A

Pb and Sn are in group IV but act like tradition metals (2+)
Ag is a transition metal but always has a charge of 1+
Although the transition metals usually have a charge of 2+, many have more that one charge

147
Q

What are the complex ions with a single charge

A 
NH4^+
H3O^+
OH^-
NO3^-
NO2^-
ClO3^-
MnO4^-
HCO3^-
148
Q

What are the complex ions with a couple charge

A 
CO3^2-
SO4^2-
SO3^2-
CrO4^2-
Cr2O7^2-
149
Q

What are the complex ions with a triple charge

A

PO4^3-

150
Q

Ammonium

A

NH4^+

151
Q

What is hydroxide

A

OH^-

152
Q

What is nitrate

A

NO3^-

153
Q

What is nitrite

A

NO2^-

154
Q

What is chlorite

A

ClO3^-

155
Q

What is permanganate

A

MnO4^-

156
Q

What is hydrogen carbonate

A

HCO3^-

157
Q

What is carbonate

A

CO^2-

158
Q

What is sulphate

A

SO4^2-

159
Q

What is sulphite

A

SO3^2-

160
Q

What is chromate

A

CrO4^2-

161
Q

What is dichromate

A

Cr2O7^2-

162
Q

What is phosphate

A

PO4^3-

163
Q

what does the ending -are represent

A

A radical containing an oxygen

164
Q

What does the ending -ite represent

A

A radical containing one less oxygen than the corresponding -ate radical.

165
Q

Covalent bonding

A

Sharing of electrons.

166
Q

What is a group of covalently bonded atoms

A

A molecule

167
Q

What is a molecule

A

A group of covalently bonded atoms

168
Q

What is a bonding pair

A

A shared electron pair

169
Q

What are lone pair

A

Pairs of electrons that do not bond

170
Q

What is a double bond

A

When there are two bonding pairs

171
Q

1

A

Mono

172
Q

2

A

Di

173
Q

3

A

Tri

174
Q

4

A

Tetra

175
Q

5

A

Penta

176
Q

Metallic bonding

A

Metal atoms loose their valance very easily leaving empty orbitals. Freed electrons able to move sassily from one metal ion to another by the force of attraction between positive ions and the “sea” of negative electrons.

177
Q

What is the relative formula mass

A

The relative mass of ionic substances

178
Q

What is the relative molecular mass

A

The relative mass of covalent substances

179
Q

How do you calculate relative mass

A

Add up the relative atomic masses of each o the elements

180
Q

What happens to the positive and negative ions that form when electrons are transferred from metal atoms to non-metal atoms

A

They are attracted to one another and form an ionic crystal lattice

181
Q

What is the best known example of an ionic crystal lattice

A

Sodium chloride ( table salt )

182
Q

What are the properties of ionic compounds

A
  • They are solids at room temperature and have high melting points
  • Solid ionic compounds do not conduct electricity but liquid ones can. Most ionic compounds dissolve in water forming and electrolyte solution that will conduct electricity
  • they are hard and brittle
183
Q

Why did ionic compounds have high melting points and whey are they solid at room temperature

A

Because the forces holding the positive and negative ions together in the crystal lattice are very strong. It thus take a lot of energy to pull ions apart.

184
Q

Why can solid ionic compounds not conduct electricity

A

Because the charged particles (ions) are not free to move.

185
Q

Why can liquid ionic compounds conduct electricity

A

Because once it is melted, the ions are free to move around and they act as a charge carrier

186
Q

Why do ionic compounds dissolved in water conduct electricity

A

Because they dissolve, the ions are free to move

187
Q

Why are ionic substances hard and brittle

A

Because when pressure is put on an ionic compound, the layers of ions move and like charged ions line up. The repulsion causes the crystal to break.

188
Q

What are intramolecular bonds

A

The covalent bonds holding the atoms in a molecule together. They are strong

189
Q

When is water a polar molecule

A

Because the nucleus of the oxygen atom has more protons than hydrogen’s nucleus

190
Q

What are intermolecular forces

A

They are the forces holding the molecules together. They are weak forces between a slightly positive side and a slightly negative side of a molecule.

191
Q

Explain how easy it would be to break he intermolecular and the intramolecular forces in water apart

A

The intermolecular forces would be easily broken, but the intramolecular forces would be very difficult to break apart.

192
Q

What do the intermolecular forces between water molecules in the sold phase result it

A

A tetrahedral arrangement

193
Q

Why does ice occupy a greater volume than water

A

Because of the tetrahedral arrangement. Thus the density of ice is less than the density of water.

194
Q

Why is ice being less fence than water not normal

A

Because usually, the solid form of a substance is more fence than it’s liquid form

195
Q

Why is it crucial to the environment that ice is less dense than water

A

Because in cold parts of the world, when water freezes, it acts as an insulator to the water below, keeping the aquatic life safe.

196
Q

What would happen if ice behaved like normal compounds

A

In cold weather, the top layer of water would freeze and sink to the bottom, this would continue to happen until the whole lake was frozen. When warmer weather came, the top layer of ice would melt, and the water would act as an insulator to the ice below

197
Q

What are the properties of covalent molecular structures

A
  • They have low melting points and are gasses at room temperature
  • They do not conduct electricity
  • Solid molecular substances are soft
198
Q

Why do covalent molecular substances have low melting points

A

Because the intermolecular forces holding the molecules together are weak

199
Q

What are examples of solid covalent molecular substances that are soft

A

Iodine crystals and bees wax

200
Q

What are covalent network structures

A

They are substances consisting of non-metal atoms covalently bonded to non-metal atoms forming giant molecules

201
Q

Why are covalent molecular substances so hard to break

A

Because they have very strong covalent bonds, and thus they have extremely high melting points

202
Q

What element bonds covalently to form giant molecules

A

Carbon

203
Q

What are allotropes

A

Different crystalline forms of the same element

204
Q

What are the two allotropes of carbon

A

Diamond and graphite

205
Q

How are the carbon atoms in diamond bonded

A

Each carbon style is covalently bonded to four other carbon atoms forming a giant molecule

206
Q

What is the meting point of diamond and why is it so high

A

It is about 3500˚C because the bonds between all the carbon atoms are extremely strong

207
Q

How are carbon atoms in graphite bonded

A

They are bonded to each other in layers. Each carbon atom is bonded to 3 other carbon atoms

208
Q

What are the bonds between the layers of graphite like, and what does this result in

A

The bonds are weak so the layers can slide over one another. This is why graphite is slippery and can be used as a lubricant.

209
Q

Why can graphite conduct electricity

A

Because it has 4 valance electrons, but only 3 are bonded, so the 4th is free to move around

210
Q

What are the properties of covalent network substances

A
  • Extremely high melting points and are solid at room temperature
  • Hard (except graphite)
  • Do not conduct electricity (except graphite)
211
Q

What are the delocalised electrons in metals ions able to do

A

Move easily from one metal ion to another in the lattice. This forms a lattice of regularly spaced positive ions.

212
Q

How is the metalic lattice held together

A

Through the force of attraction between the positive ions and the ‘sea’ of electrons

213
Q

What are the properties of metallic substances

A

They conduct heat and electricity
They are malleable and ductile
Have a high density
Have metallic lustre

214
Q

Why can metal substances conduct heat and electricity

A

Because the delocalised electrons are free to move

215
Q

Why are metallic substance malleable and ductile

A

Because the metal ions and delocalised electrons continues to hold the metal together even under tender conditions

216
Q

What does it mean that metallic substances have high density

A

The atoms are packed close to one another

217
Q

How do metallic substances have metallic lustre

A

The loosely bound electrons reflect all frequencies of light, this causes the metal to shine

218
Q

What are the particles in the crystal lattice of a covalent network

A

Atoms

219
Q

What are the particles in the crystal lattice of a covalent molecular

A

Molecules

220
Q

What are the particles in the crystal lattice of an ionic substance

A

Positive and negative ions

221
Q

What are the particles in the crystal lattice of a metallic substance

A

Positive metal ions

222
Q

What are the binding forces between particles in a covalent network substance

A

Covalent bonding

223
Q

What are the binding forces between particles in a covalent molecular substance

A

Weak intermolecular forces

224
Q

What are the binding forces between particles in an ionic substance

A

Electrostatic forces between positive and negative ions

225
Q

What are the binding forces between particles in a metallic substance

A

Forces between ions and delocalised electrons

226
Q

What is an example of a covalent network substance

A

Diamond

227
Q

What is an example of a covalent molecular substance

A

Dry ice

228
Q

What is an example of an ionic substance

A

Sodium chloride

229
Q

What is an example of a metallic substance

A

Sodium silver

Science 2017 (19 decks)

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