Unit 1 Flashcards
1
Q
Give the meaning of the term relative atomic mass.
A
average mass of all the atoms in an element compared to 1/12th the mass of a carbon-12 atom
2
Q
Ions in a mass spectrometer are deflected using…
A
Magnetic field
3
Q
Describe how the ions in a mass spectrometer are detected.
A
(Ions hit) plate/detector causing movement of electrons or (ions hit) plate/detector accept electrons
current generated
4
Q
A second mass spectrum was recorded for the same sample of silicon.
The energy of the electrons from the electron gun was higher for this second spectrum.
A
Similarities:
(Some) peak(s) at same m/z
same sample / element (is being ionised and detected)
Differences:
Additional peak(s) at ½ m/z value
Two electrons knocked out
5
Q
Van der Waals’ forces exist between all molecules.
Explain how these forces arise.
A
Electron movement in first molecule / temporary dipole
Induces a dipole in another molecule
(induced-temporary) attraction or δ+ attracts δ- in different/adjacent molecules
6
Q
Methanol (CH3OH) and methanethiol (CH3SH). ) Explain, in terms of their intermolecular forces, why the boiling points of these compounds are different.
A
(methanol) H-bonds / hydrogen bonding
(methanethiol) dipole-dipole forces or van der Waals
H-bonds are a stronger / are the strongest IMF
7
Q
Suggest how a mixture of methanol and methanethiol could be separated.
A
(Fractional) distillation
8
Q
Suggest why methaneselenol (CH3SeH) has a higher boiling point than methanethiol (CH3SH).
A
(Methaneselenol is a) bigger molecule
With stronger/more vdw forces between molecules
9
Q
Solid Cu2(OH)2CO3 is added to an excess of dilute hydrochloric acid. Suggest one observation that could be made during the reaction.
A
effervescence
10
Q
State what is meant by the term empirical formula.
A
Simplest ratio of atoms of each element in a compound
11
Q
Identify the homologous series to which octane belongs.
A
Alkanes
12
Q
Complete combustion products.
A
Carbon Dioxide and Water
13
Q
Incomplete combustion products.
A
Carbon Monoxide or Carbon (soot) and Water
14
Q
Name the type of cracking that produces a high yield Alkenes.
Give two conditions required for this process.
A
Thermal
High pressure (70 atms)
and
High temperature (500 degrees Celsius)
15
Q
State and explain the general trend in first ionisation energy across Period 3.
A
General increase
Greater nuclear charge / more protons
Same shielding / electrons added to same shell
Stronger attraction (from nucleus) for outer electron(s)
16
Q
Give one example of an element which deviates from the general trend in first ionisation energy across Period 3.
Explain why this deviation occurs.
A
Sulfur / S (lower than P)
(outer) electrons in (3)p orbital begin to pair
repel
17
Q
Table 3 shows successive ionisation energies of an element Y in Period 3.
Identify element Y.
Explain your answer using data from Table 3.
A
Sulfur / S
Large jump after 6th
18
Q
Identify the Period 3 element that has the highest melting point.
Explain your answer by reference to structure and bonding.
A
Silicon
Giant covalent structure
Covalent Bonds
Many / strong (covalent bonds) need lots of energy to break
19
Q
Explain whether the first method or the second method of production of phosphoric acid has the higher atom economy.
You are not required to do a calculation
A
Method 1
No other products formed
20
Q
State the element in Period 3 that has the highest first ionisation energy.
Explain your answer.
A
Argon / Ar
Large(st) number of protons / large(st) nuclear charge
Same amount of shielding / same number of shells / same number of energy levels
21
Q
Suggest the element in Period 3 that has the highest electronegativity value.
A
Chlorine
22
Q
Suggest what might cause the relative atomic mass of this sample to be different from the relative atomic mass given in the Periodic Table.
A
some isotopes absent/missing
23
Q
Write an equation for the reaction that occurs when a tellurium ion hits the detector.
A
Te+ + e(–) –> Te
24
Q
The mass spectrum of tellurium also has a small peak at m/z = 64.
Explain the existence of this peak.
A
2+ ion formed / 2 electrons removed From 128 (Te)
25
Predict whether the atomic radius of two isotopes are different or the same.
Explain your answer.
Same
| (Each isotope has the) same number of protons
26
Give the name of the type of crystal structure shown by silicon dioxide.
Giant covalent
27
Suggest why silicon dioxide does not conduct electricity when molten.
No delocalised electrons
28
Suggest how a student doing this experiment could check that all the water had been removed.
re-heat
| check that mass is unchanged
29
Suggest a value for the H–O–O bond angle.
100 degrees
30
State the strongest type of interaction that occurs between molecules of hydrogen peroxide and water.
Hydrogen bonds
31
Explain, in terms of electronegativity, why the boiling point of H2S2 is lower than H2O2.
Electronegativity of S lower than O
| No hydrogen bonding between H2S2 molecules only van der Waals
32
Give the meaning of the terms saturated and hydrocarbon as applied to saturated hydrocarbons.
Saturated – single carbon-carbon bonds only
| Hydrocarbon – contains carbon and hydrogen (atoms) only
33
Explain why the sulfur compounds found in crude oil should be removed from the fractions before they are used for central heating fuel.
SO2 produced
| Which causes acid rain
34
Suggest one important substance manufactured on a large scale from propene.
polypropene
35
Sodium azide has a high melting point.
Predict the type of bonding in a crystal of sodium azide.
Suggest why its melting point is high.
Ionic
Oppositely charged ions / Na+ and N3– ions
lots of energy needed to overcome (strong) attractions (between ions)
36
Give the formula of a molecule that has the same number of electrons as the azide ion.
CO2
37
Which is the correct formula of magnesium azide?
MgN6
38
```
Which one of the following is a fundamental particle that would not be deflected by an
electric field?
A electron
B neutron
C proton
```
B neutron
39
State why isotopes have similar chemical reactions.
the have the same electron configuration
40
Second ionisation energy equation for boron.
B+(g) --> B^2+(g) + e(–)
41
Explain why the second ionisation energy of boron is higher than the first ionisation energy of boron.
Electron being removed from a positive ion (therefore need more energy) to remove the electron
42
Suggest a name for this type of reaction that iron(III) nitrate undergoes.
(Thermal) decomposition
43
Suggest why the iron(III) oxide obtained is pure. Assume a complete reaction.
because there are no other solid/liquid products
44
State the block in the Periodic Table that contains nickel.
d (block)
45
Explain, in terms of its structure and bonding, why nickel has a high melting point.
```
Contains positive (metal) ions and a sea of electrons
Strong metallic bonds
```
46
Explain why nickel is ductile (can be stretched into wires).
sheets of atoms can slide over one another
47
The following equation shows how anhydrous nickel(II) chloride can be obtained from the hydrated salt using SOCl2.
Identify one substance that could react with both gaseous products.
CaCO3
48
Name the strongest attractive force between two ammonia molecules.
Hydrogen bonds
49
State how the bond between ammonia and boron trichloride is formed.
Lone pair is donated to B(Cl3)
50
Give the meaning of the term electronegativity.
The power of an atom to attract electrons towards itself in a covalent bond.
51
Give the name of the substance from which paraffin is obtained.
State the name of the process used to obtain paraffin from this substance.
Crude oil
| Fractional distillation
52
Oxides of nitrogen are also produced during the combustion of paraffin in air.
Explain how these oxides of nitrogen are formed.
Nitrogen and oxygen (from air) react
| at high temperatures
53
Give the general formula for the homologous series that contains dodecane.
CnH2n+2
54
Write an equation for the cracking of one molecule of dodecane into equal amounts of two different molecules each containing the same number of carbon atoms.
State the empirical formula of the straight-chain alkane that is formed.
Name the catalyst used in this reaction.
C12H26 --> C6H14 + C6H12
C3H7
Zeolite
55
Explain why the melting point of dodecane is higher than the melting point of the straight-chain alkane produced by cracking dodecane.
Larger molecule
| More van der Waals’ forces between molecules
56
Dodecane can be converted into halododecanes.
Deduce the formula of a substance that could be reacted with dodecane to produce 1-chlorododecane and hydrogen chloride only.
Cl2
57
Thallium(I) bromide (TlBr) is a crystalline solid with a melting point of 480 ºC.
Suggest the type of bonding present in thallium(I) bromide and state why the melting
point is high.
Ionic
Oppositely charged ions / Tl + and Br– ions
Strong attraction between ions
58
Identify which one of the isotopes of X is deflected the most in the magnetic field of a mass spectrometer. Give a reason for your answer.
number
| Lowest mass / lowest m/z
59
Explain how the current in a mass spectrometer is generated.
Electron(s) transferred / flow (at the detector)
| (From detector / plate) to the (+) ion
60
State one hazard associated with carbon.
causes global dimming
61
Other than cracking, give one common use of Y.
Jet fuel
62
Identify a catalyst used in a catalytic converter and why other than cost it is used.
platinum
| it can withstand high temperatures
63
Deduce the type of crystal structure shown by graphane.
macromolecular
64
State how two carbon atoms form a carbon–carbon bond in graphane.
bond due to the shared pair of electrons
65
Deduce the empirical formula of graphane.
CH
66
Phosphine (PH3) has a structure similar to ammonia.
| In terms of intermolecular forces, suggest the main reason why phosphine is almost insoluble in water.
(Phosphine) does not form hydrogen bonds (with water)
67
An aluminium chloride molecule reacts with a chloride ion to form the AlCl4− ion.
Name the type of bond formed in this reaction. Explain how this type of bond is formed in the AlCl4− ion.
Coordinate / dative (covalent)
| Electron pair on Cl– donated to Al(Cl3)
68
Aluminium chloride has a relative molecular mass of 267 in the gas phase.
Deduce the formula of the aluminium compound that has a relative molecular mass of 267.
Al2Cl6
69
Deduce the name or formula of a compound that has the same number of atoms, the
same number of electrons and the same shape as the AlCl4− ion.
SiCl4
70
Explain why the TlCl2+ ion has the shape that you have drawn .
(electrons in) the bonds repel to be as far apart as possible
71
Which one of the first, second or third ionisations of thallium produces an ion with the electron configuration [Xe] 5d106s1?
Second
72
Identify the Period 2 element, from carbon to fluorine, that has the largest atomic radius. Explain your answer.
Carbon / C
smallest nuclear charge
Similar shielding
73
State the general trend in first ionisation energies from carbon to neon.
Deduce the element that deviates from this trend and explain why this element deviates from the trend.
Increase
Oxygen / O
Paired electrons in a (2)p orbital
(Paired electrons in a p orbital) repel
74
Deduce the element in Period 2, from lithium to neon, that has the highest second ionisation energy.
Lithium
75
Predict the type of crystal structure in solid zinc fluoride and explain why its melting point is high.
```
Ionic
Strong (electrostatic) attraction (between ions)
between oppositely charged ions / + and – ions / F– and Zn2+ ions
```
76
Give the general formula of the homologous series of straight-chain bromoalkanes that contains one bromine atom per molecule
CnH2n+1Br
77
Suggest one reason why 1-bromohexane has a higher boiling point than Z.
Stronger / more vdw (forces) between molecules
78
State the meaning of the term mass number of an isotope.
(Total number of) protons and neutrons (in nucleus of
| atom)
79
In a mass spectrometer, the isotopes of an element are separated.
Two measurements for each isotope are recorded on the mass spectrum.
State the two measurements that are recorded for each isotope.
m/z
| (relative) abundance
80
Give one reason why the second ionisation energy of silicon is lower than the second ionisation energy of aluminium.
electron in silicon is more shielded
81
Predict the element in Period 3 that has the highest second ionisation energy.
Give a reason for your answer.
Sodium / Na
| Electron (removed) from the 2nd shell / 2p (orbital)
82
The following table gives the successive ionisation energies of an element in Period 3.
Identify this element.
Silicon
83
Explain why the ionisation energy of every element is endothermic.
energy is needed to overcome the attraction between
the (negative) electron and the (positive) nucleus or
protons
84
Suggest why the electronegativity of the elements increases from lithium to fluorine
bigger nuclear charge
| similar shielding
85
State the type of bonding in lithium fluoride.
| Explain why a lot of energy is needed to melt a sample of solid lithium fluoride.
```
Ionic
Strong (electrostatic) attractions
between oppositely charged Li+ and F- ions
```
86
Deduce why the bonding in nitrogen oxide is covalent rather than ionic.
Small electronegativity difference / they are both non-metal
87
Suggest the type of crystal shown by OF2
(simple) molecular
88
Both C3H8 and C4H10 can be liquefied and used as fuels for camping stoves.
Suggest, with a reason, which of these two fuels is liquefied more easily.
C4H10
| because it is a larger molecule
89
Explain why the complete combustion of C4H10 may contribute to environmental problems.
CO2 produced is a greenhouse gas and contributes to global warming
90
Identify a compound that is used to react with the sulfur dioxide in the products of
combustion before they enter the atmosphere.
Give one reason why this compound reacts with sulfur dioxide.
calcium carbonate
| Neutralises the SO2
91
Ethanethiol and ethanol molecules have similar shapes.
| Explain why ethanol has the higher boiling point.
because Ethanol contains Hydrogen bonding
| Which is stronger than van der waals in ethanethiol
92
Suggest why a leak of NO2 gas from the Ostwald Process will cause atmospheric pollution.
NO2 contributes to acid rain
93
Give one reason why excess air is used in the Ostwald Process.
ensure complete combustion takes place
94
Ammonia reacts with nitric acid as shown in this equation.
NH3 + HNO3 → NH4NO3
Deduce the type of reaction occurring.
Neutralisation
95
Explain why the AsCl4+ ion has a bond angle of 109.5º
There are 4 pairs of electrons
| and the electron pairs repel equally
96
Explain how the gaseous atoms of rubidium are ionised in a mass spectrometer.
Electron gun
| Knock out electron(s)
97
State one reason why the first ionisation energy of rubidium is lower than the first ionisation energy of sodium.
more shells in Rb so there is more shielding in Rb
98
By reference to the relevant part of the mass spectrometer, explain how the abundance
of an isotope in a sample of rubidium is determined.
Detector
| detects the flow of electron as an electric current
99
Predict whether an atom of 88Sr will have an atomic radius that is larger than, smaller than or the same as the atomic radius of 87Rb. Explain your answer
Smaller
Bigger nuclear charge / more protons in Sr
Similar/same shielding
100
State why high temperatures are needed for thermal cracking.
Break (C-C or C-H) bonds
101
Suggest the formula of a reagent that could be added to alkenes in order to convert it into alkanes.
H2
102
Explain why the boiling points of alkenes and alkanes are similar
(Molecules) are similar sizes
| so have similar intermolecular forces
103
Although phosphine molecules contain hydrogen atoms, there is no hydrogen bonding between phosphine molecules.
Suggest an explanation for this.
Difference in electronegativity between P and H is too
| small
104
Suggest why graphene is an excellent conductor of electricity
Delocalised electrons / free electrons
| Able to move / flow (through the crystal)
105
Explain, in terms of its structure and bonding, why titanium has a high melting point.
Nucleus / protons / positive ions and delocalised
electrons (are attracted)
Strong attraction
106
Explain why boron trichloride has a trigonal planar shape with equal bond angles.
3 bonds
| Pairs repel equally
107
State the type of bond between Br and F in BrF3 and state how this bond is formed.
Covalent
| Shared pair of electrons
108
The boiling points of fluorine and hydrogen fluoride are –188 oC and 19.5 oC respectively.
Explain, in terms of bonding, why the boiling point of fluorine is very low.
van der Waals forces between molecules
| IMF are weak
109
Identify, from the Period 2 elements lithium to nitrogen, the element that has the largest
atomic radius.
Lithium
110
State the general trend in first ionisation energies for the Period 2 elements lithium to nitrogen.
Increase / gets bigger
111
Identify the element that deviates from this general trend, from lithium to nitrogen, and explain your answer.
Boron / B
Electron removed from (2)p orbital
Which is higher in energy
112
Identify the Period 2 element that has the following successive ionisation energies.
Carbon
113
Explain, in terms of structure and bonding, why the melting point of carbon is high.
Macromolecular / giant molecular / giant atomic
Covalent bonds in the structure
Strong (covalent) bonds must be broken or overcome /
(covalent) bonds need a lot of energy to break
114
C6H14 has structural isomers.
| Deduce the number of structural isomers with molecular formula C6H14.
5
115
State one type of structural isomerism shown by the isomers of C6H14.
Chain (isomerism)
116
An element forms an ion Q with a single negative charge that has the same electron
configuration as the nitride ion.
Identify the ion Q.
Fluoride
117
Use the Periodic Table and your knowledge of electron arrangement to write the formula of lithium nitride.
Li3N
118
Suggest one reason why the yield of nitrogen dioxide formed during this reaction is often less than expected.
some (NO2) escapes
119
Suggest one reason why it is difficult to obtain a pure sample of nitrogen dioxide from this reaction.
hard to separate the 2 gases
120
State how krypton is ionised in the mass spectrometer. Sometimes the mass spectrum of Kr has a very small peak with an m/z value of 42
Explain the occurrence of this peak.
(Beam of electrons from) an electron gun
Knocks out electron(s
The 84Kr isotope
Has 2 electrons knocked out
121
Suggest one reason why particles with the same mass and velocity can be deflected
by different amounts in the same magnetic field.
different charges
122
Explain how the detector in a mass spectrometer enables the abundance of an isotope to be measured.
(ions hit detector and) cause current/(ions)
| current proportional to abundance of the isotope
123
State the type of reaction that occurs when calcium carbonate reacts with nitric acid.
Neutralisation
124
State the type of bond formed between the N atom and the B atom in F2HNBF3.
Explain how this bond is formed.
dative covalent
| Lone pair on N(HF2) donated (to BF3)
125
Suggest why the melting point of sodium iodide is lower than the melting point of sodium bromide.
Iodide is a bigger ion
126
Suggest why the first ionisation energy of krypton is lower than the first ionisation energy of argon.
Kr is a bigger atom
127
Deduce the group in the Periodic Table that contains this element.
2
128
With reference to the structure shown above give one reason why ice is less dense than water.
H2O molecules (in ice) are more spread out
129
State the strongest type of intermolecular force in methane.
Van der waals
130
Identify one molecule with the same number of atoms, the same number of electrons and the same shape as the H3O+ ion.
ammonia
131
State why more than the minimum energy is not used to ionise the sample of indium.
so only one electron is knocked out
132
Give two reasons why the sample of indium must be ionised.
so that the ions can be:
Accelerated
Deflect
133
Suggest one possible danger when a metal carbonate is reacted with an acid in a sealed flask.
may explode
134
State the type of structure shown by crystals of sulfur and phosphorus.
Explain why the melting point of sulfur is higher than the melting point of phosphorus.
(Simple) molecular
S bigger molecule (than P)
So more/ stronger van der Waals‟ forces (to be broken or overcome)
135
Explain why the melting point of aluminium is higher than the melting point of sodium.
Al has a bigger charge
More free /delocalised electrons
Stronger metallic bonding
136
State two characteristics of a homologous series.
Same) General formula /
| Chemically similar
137
Suggest the strongest type of intermolecular force between CCI2F2 molecules.
dipole-dipole
138
Name the type of bond formed when a molecule of BF3 reacts with an F– ion. Explain how this bond is formed.
Coordinate/ dative (covalent)
(Lone) pair of electrons/ both electrons (on F-)
Donated from F / fluoride or donated to the BF3
139
State the bond angle in the BF4– ion.
109.5
140
Explain why the value of the first ionisation energy of sulfur is less than the value of the first ionisation energy of phosphorus.
Paired electrons in (3)p orbital
| repel
141
State the trend in first ionisation energies in Group 2 from beryllium to barium.
Explain your answer in terms of a suitable model of atomic structure.
Decreases
Atomic radius increases/ electron removed further
from nucleus or nuclear charge/ electron in higher
energy level/ Atoms get larger/ more shells
As group is descended more shielding
142
State the type of crystal structure for each of iodine and graphite.
Iodine- molecular
| Graphite- giant covalent
143
State the meaning of the term first ionisation energy.
Energy (needed) to remove one mole of electrons from one mole of atoms in the gaseous state.
144
A general trend exists in the first ionisation energies of the Period 2 elements lithium to fluorine. Identify one element which deviates from this general trend.
Oxygen
145
The first ionisation energy of aluminium is less than the first ionisation energy of magnesium.
The outer electron in Rb is in a 5s orbital (or next outer shell)
It is more shielded from the nucleus than outer electrons in Kr
146
The first ionisation energy of krypton is greater than that of bromine.
Krypton has more protons than bromine
| But its outer electrons are in the same shell (or have similar shielding)
147
Give two reasons why this reaction might not be suitable for the removal of carbon dioxide from the exhaust gases of an engine.
reaction might be too slow
| would need continuous supply of solution
148
The sodium hydroxide solution for this reaction can be made on an industrial scale, together with chlorine gas and hydrogen gas, by electrolysis of a dilute solution of sodium chloride. Suggest one commercial advantage and one environmental disadvantage of this industrial process.
commercial advantage could sell chlorine and/or hydrogen
| environmental disadvantage generation of electricity likely to lead to release of CO2
149
In terms of atomic structure, explain why the van der Waals’ forces in liquid argon are very weak.
Argon particles are single atoms with electrons closer to nucleus
Cannot easily be polarised
