GCSE EDEXCEL CHEMISTRY ADDITIONAL [C2]

Question	Answer
Topic 1 Atomic structure and the periodic table	Topic 1 Atomic structure and the periodic table
How did Mendeleev arrange the elements in the periodic table?	By using properties of these elements and their compounds. Also he used his table to predict the existence and properties of some elements that has not been discovered.
Where are the metals and non metals found in the periodic table?	1) The non metals are found on the right side. 2) The metals are found on the left side.
Describe the structure of an atom	The nucleus is in the middle of the atom. It contains protons and neutrons, which are surrounded by electrons in shells.
What is the size of the nucleus?	The nucleus of an atom is very small compared to the overall size of the atom.
What is the relative charge and relative mass of: a proton, a neutron and an electron?	1) The relative mass of a proton is 1, and the charge is +1. 2) The relative mass of a neutron is 1 and the charge is 0. 3) The relative mass of an electron is 1/200 and the charge is -1.
Atoms contain equal numbers of?	Protons and electrons
Explain the meaning of the terms: atomic number, mass number and relative atomic mass	1) The mass number tells you the total number of protons and neutrons in the atom. 2) The atomic number tells you the number of protons in the atom. 3) The relative atomic mass uses the average mass of the isotopes of an element. It has to allow for the relative mass of each isotope and its relative abundance.
How are elements arranged in the periodic table?	In order of increasing atomic number, in rows called periods. Elements with similar properties are placed in the same vertical column, called groups.
How do you calculate the relative atomic mass of an element?	First, you multiply the mass of each isotope by its relative abundance. Then you add those together. After you divide by the sum of the relative abundances.
What happens to the numbers of relative atomic masses?	The isotopes results in some relative atomic masses not being whole numbers.
What are the rules about the filling of electron shells?	1) The 1st shell allow 2 electrons. 2) The 2nd shell allow 8 electrons. 3) The 3rd shell allow 8 electrons.
What is the connection between the number of outer electrons and the position of an element in the periodic table?	The group number is always equal to the number of electrons in the outer shell.
Topic 2 Ionic compounds and analysis	Topic 2 Ionic compounds and analysis
What can atoms of different elements do?	Can form chemical bonds and join together to create new compounds.
How are ionic bonds formed?	By the transfer of electrons to produce cations and anions.
What is an ion?	An atom or group of atoms with a positive or negative charge.
What is the formation of ions?	Ions are formed when atoms lose or gain electrons in order to have full outer shells. When they lose electrons, they become positively charged and are named cations. When they gain electrons, they become negatively charged and are named anions.
Why are 'IDE' and 'ATE' used in the names of compounds?	1) When two different elements combine the compound's name is 'something -IDE'. 2) When three or more different elements combine and on of them is oxygen, the compound's name is often 'something -ATE'.
Deduce the formula of ionic compounds (including oxides, hydroxides, halides, nitrates, carbonates and sulfates) given the formula of the constituent ions.	Deduce the formula of ionic compounds (including oxides, hydroxides, halides, nitrates, carbonates and sulfates) given the formula of the constituent ions.
What is the structure of ionic compounds as a lattice structure?	1) Consists of a regular arrangement of ions. 2) Held together by strong electrostatic forces between oppositely charged ions.
Describe and explain the properties of ionic substances?	1) They have high melting points and boiling points, due to the very strong bonds between the ions. 2) They conduct electricity as solids, when molten and in aqueous solution. When in aqueous solution, the ions separate and are all free to move, so they'll carry electric current. The same happens when they malt.
Describe the solubility of common types of substances in water?	1) All common sodium, potassium and ammonium salts are soluble. 2) All nitrates are soluble. 3) Chlorides are soluble except silver and lead. 4) Sulfates are soluble except lead, barium and calcium. 5) Carbonates and hydroxides are insoluble except sodium, potassium and ammonium.
How can insoluble salts be formed as precipitates?	By the reaction of suitable substances in solutions.
What is the method needed to prepare a pure, dry sample of an insoluble salt?	You use a precipitation reaction.
How do you prepare an insoluble salt by precipitation?	1) Add 1 spatula of lead nitrate to a test tube, and fill it with distilled water. Shake it thoroughly to ensure that all the nitrate has dissolved. Then do the same with spatula 1 of sodium chloride. 2) Tip the two solutions into a small beaker, and give it a good stir to make sure it's all mixed together. The lead nitrate should precipitate out. 3) Put a folded piece of filter paper into a filter funnel, and stick the funnel into a conical flask. 4) Pour the contents of the beaker into the middle of the filter paper. 5) Swill out the beaker with more distilled water, and tip this into the filter paper, to make sure you get all the product from the beaker. 6) Rinse the contents of the filter paper with distilled water to make sure that all the soluble sodium nitrate has been washed away. 7) Then just scrape the lead chloride onto fresh filter paper and leave it to dry.
How do you form a precipitate?	You pick the right two soluble salts, they react and you get your insoluble salt. For example to make lead chloride (insoluble), mix lead nitrate and sodium chloride (both soluble).
Why is barium sulfate, given as a ‘barium meal’ to X-ray patients?	It is opaque to X-rays. It is safe to use as, although barium salts are toxic, its insolubility prevents it entering the blood.
Why did chemists use spectroscopy (a type of flame test)?	To detect the presence of elements and this led to the discovery of new elements, including rubidium and caesium.
Topic 3 Covalent compounds and separation techniques	Topic 3 Covalent compounds and separation techniques
What is a covalent bond?	A pair of electrons shared between two atoms.
What happens when atoms make covalent bonds with one or more other atoms?	They form a molecule.
Explain the formation of simple molecular, covalent substances using dot and cross diagrams?	hydrogen, hydrogen chloride, water, methane, oxygen, carbon dioxide.
Classify the different types of elements and compounds?	1) Sodium chloride, Magnesium sulfate and copper sulfate all conduct electricity when dissolved, but not when solid. 2) Hexane and liquid paraffin doesn't conduct electricity at all and have low melting and boiling points. 3) Silicon oxide doesn't conduct electricity and have high melting and boiling points. 4) Sucrose doesn't conduct electricity even in solution. It has a low melting point and is soluble in water.
Describe the properties of typical simple molecular, covalent compounds?	1) Low melting points and boiling points. 2) Poor conduction of electricity.
What are the differences between the properties of simple molecular, covalent substances and giant molecular, covalent substances?	1) Simple molecular- they don't conduct electricity. Melting and boiling points are low. 2) Giant molecular- have very high melting and boiling points. They don't conduct electricity, except graphite. They are insoluble in water.
Explain why graphite is used to make electrodes and as a lubricant, whereas diamond is used in cutting tools?	Each carbon atom only forms three covalent bonds, creating sheets of carbon atoms which are free to slide over each other. This makes graphite useful as a lubricant. Three out of each carbon's four outer electrons are used in bonds, there are lots of spare electrons. These electrons can move, so graphite is a good conductor of electricity. Each carbon atom forms four covalent bonds in a very rigid giant covalent structure, which makes diamond very hard. This makes diamonds great as cutting tools.
Describe the separation of two immiscible liquids?	1) If two immiscible liquids are shaken together, when they are allowed to stand they will separate out into layers. 2)The denser liquid sinks to the bottom and the less dense one forms a layer on the top. 3)These layers can be separated using a separating funnel with a tap. The tap can be opened to drain off the denser liquid into a beaker. A mixture of oil and water can be separated in this way.
Describe the separation of mixtures of miscible liquids?	1) Air is filtered to remove dust. 2) It's then cooled to around -200c and becomes a miscible mixture of liquids. 3) During cooling water vapour condenses and is removed. 4) Carbon dioxide freezes and is removed. 5) The liquefied air then enters the fractionating column and is heated slowly. 6) The remaining gases are separated by fractional distillation. Oxygen and argon come out together so another column is used to separate them.
Describe how paper chromatography can be used to separate and identify components of mixtures?	1) Put spots of each mixture being tested on a pencil baseline on filter paper. 2) Roll up the paper and put it in beaker containing a solvent, such as ethanol or water. The baseline must be kept above the level of the solvent. 3) The solvent seeps up the paper, taking the samples with it. 4) The different chemicals in the sample form separate spots on the paper. 5) The result of chromatography analysis is called a chromatogram. A chromotagram with four spots means there are at least four different substances in the sample mixture.
Evaluate the information provided by paper chromatograms, including the calculation of Rf values.	One use of chromatography is to separate out the mixture of colouring agents in food. An (Rf) value is the ratio between the distance traveled by the dissolved substance and the distance traveled by the solvent. (Rf) values are used in the food industry and in forensic science.
Topic 4 Groups in the periodic table	Topic 4 Groups in the periodic table
Classify elements as alkali metals, halogens, noble gases, and transition metals based on their position in the periodic table?	1) Alkali metals- (group 1). 2) Halogens- (group 7). 3) Noble gases- (group 0) . 4) Transition metals (centre block of the periodic table).
Describe the structure of metals?	They have a regular arrangement of positive ions surrounded by a sea of delocalised electrons.
Describe and explain the properties of metals?	1) They conduct electricity well. This makes them great for making electrical wires. 2) They're malleable, this means they can be bent or hammered into different shapes.
What are the typical properties of transition metals?	1) They have high melting points. 2) They form very colourful compounds.
Elements and compounds can be classified as?	1) ionic 2) simple molecular covalent 3) giant molecular covalent 4) metallic Each type of substance has different physical properties.
Describe an alkali metal?	1) They're soft. 2) They have low melting points.
Describe the reactions of lithium, sodium and potassium with water to form hydroxides?	The reaction makes an alkaline solution. The reaction of an alkali metal with water produces hydrogen, this is why you can see fizzing.
Describe the pattern in reactivity of the alkali metals lithium, sodium and potassium with water?	1) Lithium takes longer than sodium or potassium to react, so its the least reactive. 2) Potassium takes the shortest time to react of these three elements, so its the most reactive. 3) The elements in group 1 get more reactive as the atomic number increases.
What are the colours and physical states of the halogens at room temperature?	1) Chlorine is a fairly reactive, poisonous, dense green gas. 2) Bromine is a dense, poisonous, orange liquid. 3) Iodine is a dark grey crystalline solid.
Describe the reaction of halogens with metals to form metal halides?	Halogens react with most metals, including iron and aluminium, to form salts called metal halides. 2Al(s)+3Cl2(g)=2AlCl3(s) (Aluminium Chloride). 2Fe(s)+3Br2(g)=2FeBr3(s) (Iron(IIII) bromide).
What do halogens react with?	Halogens react with hydrogen to produce hydrogen halides which dissolve in water to form acidic solutions.
What is the displacement reactions of halogens reacting with halide ions in solution?	When halides dissolve in water, the halide ions are free to react. If a more reactive halogen reacts with a solution containing halide ions it will 'push out' the less reactive halogen.
Describe the relative reactivity of the halogens?	The relative reactivity of the halogens are shown by their displacement reactions with halide ions in aqueous solution.
Why are the noble gases chemically inert?	They don't react with much at all because they have a full outer shell. This means they're not desperate to give up or gain electrons.
How did the chemists discover the noble gases?	1) They noticed that the density of nitrogen made in chemical reactions was different to the density of nitrogen taken from the air. 2) They hypothesised that the nitrogen obtained from the air must have other gases mixed in with it. 3) They also discovered different noble gases through a series of experiments.
What are the uses of noble gases?	1) Argon is used to provide an inert atmosphere in filament lamps (light bulbs). 2) Argon is non-flammable so it stops the very hot filament lamps from burning away. 3) Helium is used in airships and party balloons. Has a low density than air, so it makes balloons float.
What are the patterns in the properties of the noble gases?	The boiling point and the densities of the noble gases increase as you move down the group. (Helium, neon argon, krypton, xenon and radon).
Topic 5 Chemical reactions	Topic 5 Chemical reactions
How would you measure the temperature changes during any of these four reactions? 1) salts dissolving in water 2) neutralisation reactions 3) displacement reactions 4) precipitation reactions	You can measure the amount of energy produced by a chemical reaction in solution by taking the temperature of the reactants, mixing them in a polystyrene cup and measuring the temperature of the solution at the end of the reaction.
What is an exothermic reaction?	Gives out energy to the surroundings in the form of heat, shown by a rise in temperature. Burning fuels gives out a lot of heat. Also explosions are exothermic.
What is an endothermic reaction?	Takes in energy from the surroundings in the form of heat, shown by a fall in temperature. Including photosynthesis or dissolving ammonium nitrate in water.
The breaking and making of bonds are what?	1)The breaking of bonds are endothermic 2) The making of bonds are exothermic.
What is the overall heat energy change for a reaction?	Exothermic: The heat energy released in forming bonds in the products is greater than the energy used in breaking old bonds in the reactants. Endothermic: The energy required to break old bonds in the reactants is greater than the heat energy released when new bonds are formed in the products.
Draw and interpret simple graphical representations of energy changes occurring in chemical reactions	Draw and interpret simple graphical representations of energy changes occurring in chemical reactions
Investigate the effect of temperature, concentration and surface area of a solid on the rate of a reaction such as hydrochloric acid and marble chips	Investigate the effect of temperature, concentration and surface area of a solid on the rate of a reaction such as hydrochloric acid and marble chips
How do you investigate the reaction of Marble chips and Hydrochloric acid?	1) Measure the volume of gas evolved with a gas syringe and take readings at regular intervals. 2) Make a table of readings and plot a graph with time on the x-axis and volume on the y-axis. 3) Repeat the experiment with exactly the same volume of acid, and exactly the same mass of marble chips, but with the marble more crunched up ( so it has a bigger surface area). 4) Then repeat with the same mass of powdered marble instead of marble chips. 5) The experiment can also be used to test how the concentration of acid affects the rate of reaction. The concentration of the HCl is changed each time whilst the other factors remain the same.
How do the rates of chemical reactions vary?	The rates of chemical reactions vary from very fast, explosive reactions to very slow reactions.
Describe the effect of changes in temperature, concentration and surface area of a solid on the rate of reaction	Describe the effect of changes in temperature, concentration and surface area of a solid on the rate of reaction
What is the effect of using finer particles of a solid?	An increase in surface areas causes more collisions, so the rate of reaction is faster.
Do all collisions lead to a reaction?	Not all collisions lead to a reaction, especially if particles collide with low energy.
What is a catalyst?	A catalyst is a substance which changes the speed of a reaction, without being used up in the reaction.
What is the effect of a catalyst on the rate of reaction?	1) A catalyst works by lowering the energy required by the reactants to react. 2) This makes it easier for the reaction to happen and increases the rate of reaction. 3) This means that a lower temperature can be used, without the rate of reaction dropping.
What do catalytic converters in cars have?	1) Have a high surface area to increase the rate of reaction of carbon monoxide and unburnt fuel from exhaust gases with oxygen from the air to produce carbon dioxide and water. 2) work best at high temperatures.
Topic 6 Quantitative chemistry	Topic 6 Quantitative chemistry
Calculate relative formula mass given relative atomic masses	Calculate relative formula mass given relative atomic masses
Calculate the formulae of simple compounds from reacting masses and understand that these are empirical formulae	Calculate the formulae of simple compounds from reacting masses and understand that these are empirical formulae
How do you find the empirical formula?	1) List all the elements in the compounds. 2) Underneath them, write their experimental masses. 3) Divide each mass by the A, for that particular element. 4) Turn the numbers you get into a simple ratio by multiplying or dividing them by well-chosen numbers. 5) When the ratio is in its simplest form, this tells you the empirical formula of the compound.
Determine the empirical formula of a simple compound, such as magnesium oxide	Determine the empirical formula of a simple compound, such as magnesium oxide
Calculate the percentage composition by mass of a compound from its formula and the relative atomic masses of its constituent elements	Calculate the percentage composition by mass of a compound from its formula and the relative atomic masses of its constituent elements
Use balanced equations to calculate masses of reactants and products	Use balanced equations to calculate masses of reactants and products
What is the yield of a reaction?	The yield of a reaction is the mass of product obtained in the reaction.
What is the actual yield of a reaction?	The actual yield of a reaction is usually less than the yield calculated using the chemical equation (theoretical yield).
Calculate the percentage yield of a reaction from the actual yield and the theoretical yield?	Percentage yield= actual yield (grams)/ theoretical yield (grams) * 100.
why do reactions not give the theoretical yield?	1) incomplete reactions 2) practical losses during the preparation 3) competing, unwanted reactions.
What are the disadvantages of reactions producing waste products?	1) They are not commercially useful 2) They can present economic, environmental and social problems for disposal.
Chemists in industry work to find the economically most favourable reactions where?	1) The percentage yield is high. 2) All the products of the reaction are commercially useful. 3) The reaction occurs at a suitable speed.
Describe atoms of a given element?	Having the same number of protons in the nucleus is unique to that element.

Next up

GCSE EDEXCEL CHEMISTRY ADDITIONAL [C2]

Description

Resource summary

Similar

	Created by Jake Turner Retros almost 9 years ago