Carbon 14 has a mass number of 14 and an atomic number of 6. Which is the correct statement about this atom?
It has 8 protons, 6 neutrons, and 8 electrons
It has 6 protons, 8 neutrons, and 6 electrons
It has 14 protons, 8 neutrons, and 14 electrons
It has 6 protons, 14 neutrons, and 6 electrons
How are the electrons arranged in the atom?
As part of the nucleus
All atoms are equally distributed in one shell.
In several shells, all of which contain 8 electrons.
In several shells: the innermost can take 2 electrons, and the second shell can take up to 8 electrons.
The electron arrangement of calcium is 2, 8, 8, 2. Which one statement is correct?
Calcium has a mass number of 20 and forms 6 - ions
Calcium has an mass number of 20 and forms 2+ ions
Calcium forms 6- ions and has 20 protons
Calcium forms 2+ ions and has 20 protons
In chemical reactions, the change occurs due to
Rearrangement of the protons
Rearrangement of the neutrons
Rearrangement of the electrons
Rearrangement of both protons and neutrons
An isotope of an element has:
The same number of electrons, but different numbers of protons
The same number of protons but different number of neutrons.
The same number of neutrons but different numbers of protons
Same number of neutrons, but different numbers of electrons
When elements react, their electron
arrangement becomes more stable. The electron shell become adopt a structure that is based on:
the alkali metals
the transition metals
the halogens
the noble gases
The Group I metals achieve a stable structure by:
losing 1 electron
gaining 1 electron
gaining 7 electrons
losing all their electrons
Which one of these statements is true about ionic bonding
Ions are held by the attractive force of like charges
Ions are held together by the attractive force of opposite charges
Ionic compounds never dissolve in water.
Ionic compounds are always very unstable.
When electroplating is done, the object to be plated is placed at:
The anode
The cathode
Either the anode or the cathode
At the bottom of the cell.
Covalent bonds are made by:
the strong attraction between nuclei
the strong attraction between positive and negative ions.
the sharing of electrons between atoms
None of the above
Iodine sublimates at 30 degrees Celsius. Sublimation is:
decomposition
turning from a gas to a liquid without going through a solid phase
turning from a liquid to a gas without passing through a solid phase
turning from a solid to a gas without passing through a liquid phase.
The CORRECT definition of a molecule is:
atoms of the same or different elements ionically bonded.
atoms of the same or different elements covalently bonded
atoms of different elements only that are covalently bonded
atoms of the same element only that are covalently bonded.
Which one of these is NOT a property of simple molecular structures?
Conduction of electricity
Liquids or gases at room temperature
Brittle when solid
Do not dissolve in water
Which one of these IS a property of giant molecular structures?
Conducting electricity
Dissolves in water
Is hard
melts at low temperatures
Diamond is a giant molecular structure formed from carbon. So is graphite. Which one of these correctly explains why diamond is hard and graphite is soft?
Diamond is made up of hexagonal structures
with weak bonds between the layers.
Graphite is made up of tetrahedral structures with
strong bonds between layers.
Diamond is made up of tetrahedral structures with strong bonds between the layers
Diamond is made up of alternate layers of C4+ ions and C4- ions.
Which other substance has a giant molecular structure like diamond?
Sodium chloride
Silicon dioxide
Carbon dioxide
Sulphur hexafluoride
Which one of these is a test for a real diamond?
It will cut glass
It fizzes if dilute hydrochloric acid is put on it.
It melts at exactly 347 degrees celsius.
It conducts electricity.
Perfumes are often dissolved in a solvent. Which one of these is the most common solvent for perfumes?
Water
Hexanoic acid
Octane
Ethanol
Which one of these statements is the correct description of metallic bonding?
Metals share electrons to form giant covalent structures.
Metal are held together by uneven
distribution of charge.
Metals hold electrons
loosely, and are a lattice of ions on a sea of free electrons.
Metals are free ions in a lattice of fixed electrons.
When a voltage is applied across the ends of a metal wire, a current flows because:
the delocalised metal ions drift about randomly but there is an overall drift in a given direction.
the delocalised electrons drift about randomly but there is an overall drift in a given direction.
the application of a voltage ionises the metal and releases the electrons.
the voltage breaks the bonds so that metal atoms circulate through the wire carrying the charge.
When metals are mixed together they:
conduct electricity
react violently
separate out again
form alloys
Which one of these is a correct physical property of the alkali metals?
They are hard
They conduct electricity badly
They melt at low temperatures.
They have a very high density
When alkali metals react with water, they form a hydroxide, the pH of which is:
3
7
10
14
When lithium is added to water, it fizzes. When caesium is added to water it will:
explode.
fizz with a purple flame.
float on the water without reacting.
sink without reacting.
A deputy headmaster helped the Head of Chemistry by removing 200 grams of sodium from the chemistry department. He disposed of it by flushing it down the lavatory. Which one of these was the correct outcome of the deputy headmaster's actions? (This is a true story)
Nothing.
He later got a complaint from the water authority that the waste water from his property was very alkaline.
It fizzed a bit but flushed away. The lavatory bowl was very clean afterwards.
There was a massive explosion that blew the stack-pipe off the wall and shattered the lavatory bowl.
To gain a noble gas structure the alkali metals have to
lose one electron
lose two electrons
gain one electron
gain seven electrons
Which one of these is the only method that can be used to extract alkali metals from their ores?
Electrolysis
Reduction using hydrogen gas
Reduction using carbon at high temperatures.
Treating with very strong acids
Which one of these non-metals is a halogen?
Sulphur
Hydrogen
Bromine
Oxygen
When halogens react with metals, they form
hydroxides
salts
oxides
noxious and toxic gases
To gain noble gas structure, halogens have to
lose one electron
lose seven electrons
gain one electron
remain the same; they already have noble gas structure
Which statement is the correct one about the reactivity of the halogens?
They get less reactive as you go down the group.
They get more reactive as they go down the group.
They are all equally reactive.
The reactivity
within the group is random.
If we add chlorine to potassium bromide, what will happen?
There is no reaction
Bromide ions will react with the chlorine gas to form chlorine bromide.
Potassium chloride and water are formed.
Potassium chloride and bromine gas are formed
Which one of these is NOT a property of nanomaterials?
they can act as catalysts
they can be made to target cells for treatment.
they react very easily
they can be made into tiny electronic components.
A photochromic material is one which:
changes colour when exposed to light.
changes colour with different temperatures
decomposes when exposed to light.
conducts electricity when exposed to light
Which one of these actions should you take to make sure that a chemical equation is balanced?
Make sure that the total number of product atoms is the same as the total number of reactant atoms
No action at all. All chemical reactions automatically balance out.
Make sure that the number of atoms for each atom is the same on each side
Make sure that there are half the number of atoms of each element left, as some atoms are destroed to provide the energy for the reaction
Farmers use ammonium nitrate, NH4NO3, as a fertiliser. Which statement gives the correct formula mass AND the correct percentage of nitrogen? Nitrogen - 14; hydrogen - 1; oxygen - 16.
Formula mass = 31 and percentage of N = 45 %
Formula mass = 80 and percentage of N = 17.5 %
Formula mass = 80 and percentage of N = 35 %
Formula mass = 84 and percentage of N = 23 %
What is the mass of 1 mole of calcium carbonate? (Ca = 40; C = 12; O = 16)
68 g
100g
680 g
1000 g
How many particles are there in 1 mole of calcium carbonate?
1.6 x 10-19
1.6 x 1010
6 x 1018
6 x 1023
How many moles are there in 10 g magnesium sulphate? (Mg = 24, S = 32, O = 16)
0.096 mol
0.14 mol
0.083 mol
12 mol
1 mol copper has a
mass of 63.5 g. The simplest reason for this is that:
there are isotopes of copper within the sample, so this figure is an average.
there must be impurities within the sample.
copper is a very unstable element which is decaying rapidly.
some samples of copper have half an extra proton, while other samples have half an extra neutron.
The mole is defined as the mass of the same number of particles as there are in:
1 g hydrogen atoms
1 g hydrogen molecules
7 g lithium atoms
12 g carbon atoms
Often reactions do not give 100 % of the expected yield. Which one of these is NOT a reason for this happening?
Some product has been lost.
Some product matter has been destroyed
The reaction has not gone to completion
Some unwanted products have been formed.
Which one of these reactions is reversible?
caesium + fluorine --> caesium fluoride
methane + oxygen --> carbon dioxide + water
ammonia + hydrogen chloride --> ammonium chloride
sodium hydroxide + hydrochloric acid --> sodium chloride + water
Which one of these statements correctly describes equilibrium?
The mass of the reactants = mass of the products
The rate of forming products is the same as products turning back into reactants.
The reaction is stable and under control.
The reaction needs a
catalyst to make it go.
Which statement correctly describes the action of a catalyst?
It increases the rate of reaction.
It increases the yield.
It gets used up in the reaction.
It changes the equilibrium to favour the products.
A certain reversible reaction is exothermic. A chemist decides to help the reaction along by heating it to a high temperature. Which one of these describes what actually happens?
The reaction goes to completion
The reaction goes forward to produce more products
The reaction goes backwards to produce more reactants.
The reaction goes back completely to the reactants.
When sulphur trioxide is made, it is made under high pressure. The reason for this is:
the high pressure increases the chance of a successful collision to make sulphur trioxide.
the high pressure moves the reaction in favour of the reactants.
the high pressure is essential for the catalyst to work.
the high pressure avoids the need for an expensive catalyst.
Which one of these is the correct catalyst used in the Haber process?