instruction stringlengths 19 307 | input float64 | output stringlengths 1 510 |
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Suggest two reasons why 9 carat gold is often used instead of pure gold to make jewellery. | null | 9 carat gold is cheaper so lower cost. Pure gold is soft so less durable. 9 carat gold is harder |
The names and formulae of three hydrocarbons in the same homologous series are:
Ethane C2H6
Propane C3H8
Butane C4H10
The next member in the series is pentane.
What is the formula of pentane? | null | C5H12 |
Which homologous series contains ethane, propane and butane? | null | Alkanes |
Octane (C8H18) is a hydrocarbon found in petrol. Explain why octane is a hydrocarbon. | null | Octane contains hydrogen and carbon |
What is the total number of protons and neutrons in an atom called? | null | The mass number |
Carbon reacts with oxygen to produce carbon dioxide (CO2). | null | 2 |
What is the total number of atoms in one molecule of carbon dioxide? | null | 3 |
Sometimes carbon reacts with oxygen to produce carbon monoxide (CO). Calculate the relative formula mass (Mr) of carbon monoxide.
Relative atomic masses (Ar): C = 12; O = 16 | null | 28 |
Calculate the percentage by mass of carbon in carbon monoxide. | null | 42.9 |
An instrumental method is used to measure the amount of carbon dioxide in
the air. Give one reason for using an instrumental method. | null | Accurate, sensitive, rapid, small sample |
Why are nanoparticles effective in very small quantities? | null | They have a high surface area to volume ratio |
Give one advantage of using nanoparticles in sun creams. | null | Better coverage and more protection from the Sun’s ultraviolet rays |
Give one disadvantage of using nanoparticles in sun creams. | null | Potential cell damage to the body and harmful effects on the environment |
A coarse particle has a diameter of 1 × 10−6 m.
A nanoparticle has a diameter of 1.6 × 10−9 m.
Calculate how many times bigger the diameter of the coarse particle is than the diameter of
the nanoparticle. | null | 1/1.6 = 0.65 and 10^-9 - 10^-6 = 10^3, 0.625 x 1000 = 625 times bigger |
A student tested a metal chloride solution with sodium hydroxide solution.
A brown precipitate formed.
What was the metal ion in the metal chloride solution? | null | Iron (III) |
Complete the sentence.
Atoms of carbon have no overall electrical charge because the number
of protons is the same as the number of ....... . | null | electrons |
Which is the correct formula for butane? | null | C4H10 |
Complete the sentences.
The atomic number of an atom is the number of ... | null | Protons or electrons |
Complete the sentences. The mass number of an atom is the number of | null | protons plus / and neutrons |
Explain why an atom has no overall charge.
Use the relative electrical charges of sub-atomic particles in your explanation. | null | (because the relative electrical charges are) −(1) for an electron and +(1) for a proton and the number of electrons is equal to the number of protons |
Explain why fluorine and chlorine are in the same group of the periodic table.
Give the electronic structures of fluorine and chlorine in your explanation. | null | (the electronic structure of) fluorine is 2,7 and chlorine is 2,8,7 (so fluorine and chlorine are in the same group) because they have the same number
of or 7 electrons in their highest energy level or outer shell |
When elements react, their atoms join with other atoms to form compounds.
Complete the sentences.
(i) Compounds formed when non-metals react with metals consist of
particles called ... | null | ions |
When elements react, their atoms join with other atoms to form compounds.
Complete the sentences.Compounds formed from only non-metals consist of
particles called ... | null | molecules |
Magnesium and dilute hydrochloric acid react to produce magnesium chloride solution and
hydrogen.
Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g) | null | effervescence / bubbling / fizzing / bubbles of gas and magnesium gets smaller / disappears |
Describe a method for making pure crystals of magnesium chloride from magnesium
and dilute hydrochloric acid.
In your method you should name the apparatus you will use.
You do not need to mention safety. | null | hydrochloric acid in beaker (or similar)
• add small pieces of magnesium ribbon
• until magnesium is in excess or until no more effervescence occurs *
• filter using filter paper and funnel
• filter excess magnesium
• pour solution into evaporating basin / dish
• heat using Bunsen burner
• leave to crystallise / leave ... |
Water from a lake in the UK is used to produce drinking water.
What are the two main steps used to treat water from lakes?
Give a reason for each step. | null | Step 1: filtration, Reason for step 1: To remove solids
Step 2: Sterilisation, Reason for step 2: to kill microbes |
Explain why it is more difficult to produce drinking water from waste water than from water
in lakes. | null | water needs more / different processes because it contains any two from:
• more organic matter
• more microbes
• toxic chemicals or detergents |
Why is producing drinking water from sea water expensive? | null | high energy requirement |
Why does iodine have a higher boiling point than chlorine? | null | The forces between iodine molecules are stronger |
Why does potassium iodide solution conduct electricity? | null | It contains ions which can move |
What are the products of electrolysing potassium iodide solution? | null | Hydrogen and iodine |
Why is aluminium positioned in Group 3 of the periodic table? | null | has three electrons in outer energy level / shell |
Silicon dioxide has a very high melting point.
Other substances are added to silicon dioxide to make glass. Glass melts at a lower
temperature than silicon dioxide.
Suggest why. | null | weaker bonds or fewer bonds or disruption to lattice |
Sodium oxide is one of the substances added to silicon dioxide to make glass.
Sodium oxide contains Na+ ions and O2– ions.
Give the formula of sodium oxide. | null | Na2O |
Glass can be coloured using tiny particles of gold. Gold is a metal.
Describe the structure of a metal. | null | lattice / regular pattern / layers / giant structure / close-packed arrangement of positive ions or atoms with delocalised electrons |
When ethene reacts with bromine, energy is required to break covalent bonds in the
molecules.
Explain how a covalent bond holds two atoms together. | null | electrostatic force of attraction between shared pair of negatively charged electrons and both positively charged nuclei |
This question is about atomic structure and the periodic table.
Gallium (Ga) is an element that has two isotopes.
Give the meaning of ‘isotopes’.
You should answer in terms of subatomic particles. | null | Isotopes are atoms with the same number of protons but with different number of neutrons. This means that they are also atoms with the same atomic number or atoms of the same element with different number of neutrons. |
Gallium was discovered six years after Mendeleev published his periodic
table.
Give two reasons why the discovery of gallium helped Mendeleev’s
periodic table to become accepted. | null | Gallium fitted in a gap Mendeleev had left and gallium's properties were predicted correctly by Mendeleev |
This question is about models of the atom.
Atoms were first thought to be tiny spheres that could not be divided.
Which particle was discovered to change this model of the atom? | null | Electrons |
The plum pudding model did not have a nucleus.
Describe three other differences between the nuclear model of the atom
and the plum pudding model. | null | Nuclear model had mostly empty space while plum pudding model has no empty space. Plum pudding model is also solid. The positive charge is all in the nucles in the nuclear model, in the plum pudding model the atom is a ball of positive charge with embedded electrons. The mass is concentrated in the nucleus in the nucle... |
Niels Bohr adapted the nuclear model.
Describe the change that Bohr made to the nuclear model. | null | The electrons are in energy levels around the nucleus / are in shells around the nucleus. The electrons orbit the nucleus now. |
Define mass number. | null | Mass number is the number of protons plus neutrons |
Why is the mass number different in the two isotopes? | null | (the isotopes contain) different numbers of neutrons |
The model of the atom changed as new evidence was discovered.
The plum pudding model suggested that the atom was a ball of positive
charge with electrons embedded in it.
Evidence from the alpha particle scattering experiment led to a change in
the model of the atom from the plum pudding model.
Explain how. | null | Mos alpha particles passed straight through the gold foil so the mass of the atom is concentrated in the nucleus / centre. Also, most of the atom is empty space while some alpha particles were deflected / reflected meaning the atom has a positively charged nucleus / centre. |
What is the centre of the atom? | null | Nucleus |
What are the two types of particles in the centre of the atom? | null | Neutron and the Proton |
James Chadwick proved the existence of what? | null | Neutron |
What particle did Niels Bohr suggest orbited the atom? | null | Neutron |
What are the two types of particles with the same mass? | null | Neutron and Proton |
Chadwick’s experimental work on the atom led to a better understanding of
isotopes.
Explain how his work led to this understanding. | null | Chadwick provided the evidence to show the existence of neutrons. He discovered neutrons. This was necessary because isotopes have the same number of protons / atomic number. Also, this was necessary because isotopes are atoms of the same element but with different numbers of neutrons. |
Name the particle in the atom that has a positive charge. | null | Proton |
Name the particle in the atom that has the smallest mass. | null | Electron |
What are lithium atoms with different numbers of neutrons called? | null | Isotopes |
How many atoms are present in one mole of fluorine atoms? | null | 6.02 × 10^23 |
Why is aluminium positioned in Group 3 of the periodic table? | null | Aluminium is positioned in Group 3 of the periodic table because it has three electrons in the outer energy level / shell |
What is the test for chlorine gas? | null | Damp litmus paper turns white |
What is always different for atoms of different elements? | null | The number of protons is always different for atoms of different elements. |
Sodium fluoride is an ionic substance.
What are two properties of ionic substances? | null | Ionic substances dissolve in water and have a high melting point. |
Why does pure water not conduct electricity? | null | no delocalised / free electrons + no overall electric charge + no ions |
Nanoparticles of cobalt oxide can be used as catalysts in the production of
hydrogen from water.
How does the size of a nanoparticle compare with the size of an
atom? | null | The size of a nanoparticle is larger than that of an atom |
Suggest one reason why 1 g of cobalt oxide nanoparticles is a better
catalyst than 1g of cobalt oxide powder. | null | Nanoparticles have larger surface area. |
In 1895, the first of a new family of elements was discovered.
One of the new elements was called helium.
Where has this new family of elements been placed in the modern periodic table? | null | This new family of elements has been placed to the right of column 7 / group 7. In group 0. |
Complete the sentence.
In the periodic table on your Data Sheet, the elements are arranged in order of their
atomic what? | null | Atomic number |
The elements in Group 0 are called what? | null | Noble gases. |
In 1869 Mendeleev produced his periodic table.
Why did Mendeleev leave gaps in his periodic table? | null | Mendeleev left gaps in his periodic table for undescovered elements. |
In which group of the periodic table are lithium and sodium? | null | Group 1 |
Some particles in the nucleus have a positive charge.
What is the name of these particles? | null | Protons |
Some particles in the nucleus have no charge.
What is the name of these particles? | null | Neutrons |
Sodium chloride is an ionic compound. What are two properties of ionic compounds? | null | Ionic compounds have high melting points and strong bonds. |
The formula of sodium chloride is NaCl
Calculate the relative formula mass of sodium chloride.
Relative atomic masses: Na = 23; Cl = 35.5 | null | 58.5 |
The relative formula mass of a substance, in grams, is one what? | null | One mole. |
Nanoparticles of sodium chloride (salt) are used to flavour crisps.
What are nanoparticles? | null | Very samll particles or 1-100nm in size particles or particle with a few hundred atoms. |
What evidence is there that:
sodium has a low melting point? | null | It melts in contact with water and melts easily |
Why does iodine not react with sodium bromide solution? | null | Iodine does not react with sodium bromide solution because it is less reactive than bromine. |
State and explain one way in which Mendeleev improved Newlands’ periodic table. | null | Mendeleev improved Newlands' periodic table by leaving gaps for undiscovered elements so that elements were in their correct group. Another way would be that he did not always folow order of relative atomic masses so that the elements were in their correct group. |
Lithium reacts with water to produce a gas and an alkaline solution. Name the gas produced. | null | Hydrogen |
Potassium is also in Group 1 of the periodic table.
Potassium reacts with water in a similar way to lithium.
Write down two differences you would see between the reactions of potassium and lithium
with water. | null | Potassium reacts faster, bubbles faster, moves faster, melts and produces purple flames. |
What evidence did Mendeleev use to decide that the alkali metals should be in the same
group? | null | They had similar properties |
Describe how the elements in the modern periodic table are arranged in terms of protons | null | In order of atomic / proton number |
Describe how the elements in the modern periodic table are arranged in terms of electrons | null | elements in same group have same number (of electrons) in outer shell |
State two properties of transition elements that make them more useful than alkali metals
for making water pipes. | null | Transition elements are stronger / harder, less reactive and have higher melting points. |
Describe and explain the trend in reactivity of the alkali metals (Group 1). | null | Reactivity increases down the group, outer electron is further from nucleus, there is less attraction between outer electron and nucleus and therefore outer electrons are lost more easily. |
What is the element used as a catalyst in the Haber process? | null | Fe (Iron) |
How do the boiling points of the halogens change down the group from fluorine to iodine? | null | The boiling points increase. |
Why does chlorine displace bromine from sodium bromide? | null | Chlorine displaces bromine from sodium bromide because chlorine is more reactive than bromine. |
Suggest which halogen could react with sodium chloride solution to produce
chlorine. | null | Fluorine |
Lithium, sodium and potassium are all in Group 1 of the modern periodic table.
Explain why. | null | Lithium, sodium and potassium are all in Group 1 of the modern periodic table because they all have one electron in the outer shell so they have similar properties and react in the same way. |
Explain why an atom has no overall charge.
Use the relative electrical charges of sub-atomic particles in your explanation. | null | An atom has no overall charge because the number of electrons is equal to the number of protons and electrons have a negative charge and protons are positive so they cancel out. |
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