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116 Cards in this Set
- Front
- Back
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How did Newlands and Mendeleev classify the elements? |
In order of their atomic weights |
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What is a group? |
A column in the periodic table containing elements with similar properties |
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Why were there errors in the early periodic table? |
Some elements had not yet been discovered |
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What does the group number show? |
The number of electrons in the outer shell of an atom |
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What are the elements of group 1 called? |
Alkali Metals |
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What ions do alkali metals form? |
+1 |
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What is the density of an alkali metal? |
Low density |
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How do alkali metals react with non-metals? What do they form? |
They form ionic compounds which are white solids and dissolve in water to produce colorless solutions |
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How do alkali metals react with water? |
They react violently and release hydrogen |
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What are hydroxides formed from? |
Alkali Metals |
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What happens when hydroxides dissolve in water? |
They give alkaline solutions |
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What are the properties of elements further down group 1? (2) |
They are more reactive They have a lower melting and boiling point |
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Why are group 1 elements more reactive, the further down you go? (4 Marks) |
The outer electron is further from the nucleus Weaker attraction to nucleus Inner electrons repel the outer electrons with more ease Electrons lost easily because bonds are easy to break because they need to lose an electron to gain a full outer shell |
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What are the properties of transition elements in comparison to alkali metals? (4) |
Higher melting points (except mercury) Higher densities Stronger and harder Much less reactive |
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What are the three other properties of transition metals? |
Have ions with different charges Form coloured compounds Are useful as catalysts |
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What are the elements of group 7 called? |
The halogens |
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What ions do group 7 elements form and what are they called? |
They form -1 charged ions called halide ions. |
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What are the properties of elements further down Group 7? (2) |
Less reactive Higher melting and boiling point |
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What are the conditions required for a more reactive halogen to displace a less reactive halogen? |
The halogen being displaced must in an aqeuous solution of its salt |
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Why are group 7 elements less reactive, the further down you go? (4 Marks) |
The outer electron is further from the nucleus Weaker attraction to nucleus Inner electrons repel the outer electrons with more ease Harder to gain electrons since they need an electron to have a full outer shell |
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Which type of water forms lather with soap? |
Soft Water |
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What does reacting hard water with soap do? |
Forms scum |
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What is the problem with hard water and scum? |
More soap is needed to form lather |
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What do soapless detergents NOT do? |
Form scum |
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What is hard water made of? |
Dissolved compounds of calcium or magnesium |
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How is hard water formed? |
When water comes into contact with rocks |
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What are the two types of hard water? |
Permanent hard water and temporary hard water |
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What is permanent hard water? |
Remains hard when boiled |
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What is temporary hard water? |
Becomes soft when boiled |
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How does temporary hard water become soft when boiled? |
Contains hydrogencarbonate ions that decompose on heating to produce carbonate ions which react with calcium and magnesium to form precipitates |
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Give the steps of measuring the hardness of water using titration with soap solution (5) |
Known volume of water is put into flask Soap solution is added Mixture is swirled to form lather Volume of soap required to form permanenent lather is recorded The harder the water, the greater the volume of soap solution required |
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How does hard water increase costs? |
More soap is required to form lather which costs more money |
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How is scale formed on kettles and heating systems? |
When temporary hard water is heated |
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What are the benefits of hard water? (2) |
Calcium compounds can be good for teeth and bones Can also help reduce heart disease |
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Give two ways in which hard water can be made soft by removing calcium and magnesium ions |
-Add sodium carbonate, which reacts with the calcium and magnesium ions to form a calcium carbonate and magnesium carbonate precipitate OR -Using ions exchange columns which replace calcium and magnesium ions with hydrogen or sodium ions |
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What is correct quality water?
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Water with low levels of salt and microbes |
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How is correct quality water produced? (3) |
Choosing an appropriate source Passing water through filter beds to remove solids Sterilising with chlorine |
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What can a water filter contain to improve taste and quality? (3) |
Carbon Silver Ion exchange resin |
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What are ion exhange resins? |
Substances packed into an ion exchange column that is used to filter water by replacing calcium and magnesium ions with sodium or hydrogen ions |
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What is the use of chlorine to purify water? |
Reduces microbes |
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What is the use of fluorine to purify water? |
Improve dental health |
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What is the consequence of using distillation to purify salt water?
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High amounts of energy is required, so costs are high |
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What is calorimetry? |
Burning a substance and using the heat given off to heat up water which is measured to know the energy released by the substance |
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Give the formula for energy released and give what each letter means |
Q = mcΔT Q = Energy released m = mass of water c = specific heat capacity of water ΔT = rise in temperature |
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How is energy measured? |
Joules (J) |
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How is the amount of energy released or absorbed in a chemical reaction calculated for reactions with solids in water or neutralization reactions? |
By measuring the temperature change of the solution when the reagents are mixed in an insulated container. |
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What do energy level diagrams show? (3) |
Relative energies of reactants and products Activation Energy Overall energy change of a reaction |
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Turn over to see an example of an exothermic energy level diagram |
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What does the curve in the middle of an energy level diagram represent? |
The activation energy |
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How can the activation energy be lowered? |
Using a catalyst |
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What does a catalyst do to an energy level diagram? |
The curve in the middle is lower than it was as the activation energy has been reduced |
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What does the letter A represent? |
Activation Energy |
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What does the letter B represent? |
Energy Change |
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What does the letter C represent? |
Energy Released |
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What happens during a chemical reaction in terms of energy? |
Energy is supplied to break bonds Energy is released when bonds are formed |
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In an exothermic reaction, the energy released from forming new bonds is greater than the... |
energy needed to break existing bonds |
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In an endothermic reaction, the energy released from forming new bonds is greater than the... |
energy released from forming new bonds |
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How do you calculate energy transferred using bond energy data given in the exam? (2) |
By adding the different bond energies on each side of the equation Eg. H-H = 436 kg/mol so 2 molecules of H-H = 436 + 436 Then you do (sum of bond energies of reactant (left side) minus sum of bond energies of product (right side)) |
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Exothermic and endothermic reactions have positive or negative energy changes? |
Exothermic = Negative energy change Endothermic = Positive energy change |
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Give the equation for the combustion of hydrogen |
hydrogen + oxygen = water |
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What are hydrogen fuel cells used for? |
To produce electricity to power vehicles |
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What are the two tests for testing an unknown positive ion solution? |
Flame test Reaction with Sodium Hydroxide |
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What is the colour of lithium compounds in a flame test? |
Crimson Flame |
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What is the colour of sodium compounds in a flame test? |
Yellow Flame |
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What is the colour of potassium compounds in a flame test? |
Lilac Flame
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What is the colour of calcium compounds in a flame test? |
Red Flame
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What is the colour of barium compounds in a flame test? |
Green Flame |
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What are the two precipitate types that can be formed during a reaction with sodium hydroxide and positive ions? |
Coloured precipitate
White precipitate |
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What is a precipitate? |
A solid substance that comes out of a solution during a reaction |
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What positive ions form a white precipitate when reacted with sodium hydroxide? |
Aluminum, calcium and magnesium ions |
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Which of the three positive ions that form a white precipitate when reacted with sodium hydroxide dissolves in excess sodium hydroxide? |
Aluminum ions |
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How do you differentiate between calcium and magnesium ions? |
Carry out a flame test, the calcium will burn with a red flame |
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What positive ions form a coloured precipitate when reacted with sodium hydroxide? |
Copper(II), Iron(II) or Iron (III) ions |
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What colour precipitate does copper (II) form when reacted with sodium hydroxide? |
Blue Precipitate |
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What colour precipitate does Iron (II) form when reacted with sodium hydroxide? |
Green Precipitate |
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What colour precipitate does Iron (III) form when reacted with sodium hydroxide? |
Brown Precipitate |
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What is the test for if carbonates are present? (3 steps) |
Add dilute acid Fizz should be produced. If not, carbonate doesn't exist The fizz gas can be bubbled through limewater, which turn cloudy (precipitate is formed) if carbonate is present. |
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What is the test for if halides (chloride, bromide and iodide) are present? (3 steps) |
Add dilute nitric acid Add silver nitrate If precipitate is formed, halide exists |
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What colour precipitate do chloride ions form when reacted with dilute nitric acid? |
White Precipitate |
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What colour precipitate do bromide ions form when reacted with dilute nitric acid? |
Cream Precipitate |
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What colour precipitate do iodide ions form when reacted with dilute nitric acid? |
Yellow Precipitate |
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What is the test for if sulfates are present? (3 steps) |
Add dilute hydrochloric acid Add barium chloride solution White precipitate is formed if sulfates exist |
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What is titration used for? |
The volumes of acid and alkali solutions that react with each other to become neutralised |
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Give the steps for titration |
Add a known volume of alkali into a conical flask using a pipette Add a few drops of indicator Pour acid into burette and record the reading on the burette Open the tap and add a small amount of acid and swirl the conical flask to mix Keep adding acids at regular intervals until the alkali is neutralised Repeat 3 times for accurate results |
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What two pieces of data are required to find the concentration of a reactant in titration |
The concentration of the other reactant The results from a titration experiment |
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How many cm3 is 1 decimetre cubed? |
1000cm3 |
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What is a mole? |
The mass of a substance in terms of its relative formula mass in grams. eg. 1 mole of a substance is its RFM in grams eg. RFM of NaOH = 40. So 1 mole of NaOH is 40g |
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Give the steps for calculating the concentration of a solution in moles/dm3 (6) |
Write acid on the left and alkali on the right Write conc. x volume on the left Write conc. x volume on the right Fill in the empty conc. and volumes on both sides Leave the unknown conc. and volumes as 'x' Put an equals sign between the left ad right sides and solve the equation |
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Give the steps for calculating the concentration of ethanoic acid in grams/dm3 if the Mr of ethanoic acid is 60 (3) |
60 = 60g per mole Use the value of moles/dm3 in a previous question multiply the moles/dm3 by the Mr which is 60 in this case |
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Go on the internet now and do some practice titration calculations |
Go on the internet now and do some practice titration calculations |
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What are the raw materials for the Haber process? |
Nitrogen and Hydrogen |
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Where is Nitrogen obtained from? |
From the air |
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Where is Hydrogen obtained from? |
Natural gas or other sources |
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What are the conditions required for the Haber process? |
Iron catalyst 450 degrees Celsius Pressure of 200 atmospheres |
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Give the equation for the Haber process |
Nitrogen + Hydrogen <--> ammonia |
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What happens when the reaction cools down? (2) |
Ammonia liquefies and is removed Remaining hydrogen and nitrogen are recycled |
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What is equilibrium? |
When a reversible reaction occurs in a closed system and reactions occur at the same rate in each direction |
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The relative amounts of all the reacting substances at equilibrium depend on the __________________________ |
conditions of the reaction |
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What happens when temperature is raised in a reversible reaction? |
Yield from endothermic reaction increases
Yield from exothermic reaction decreases |
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What happens when temperature is lowered in a reversible reaction? |
Yield from endothermic reaction decreases Yield from exothermic reaction increases |
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Why is a 450 degrees temperature required for the Haber process? (3) |
Producing Ammonia is exothermic so a lower temperature means higher yield. However, the temperature can't be too low otherwise the rate of reaction will be very slow. SO 450 degrees is optimum |
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Why is a high pressure required for the Haber process? |
Because in gaseous reactions like the Haber process, an increase in pressure will favour the reaction that produces the least number of molecules in the equation: N2 + 3H2 <--> 2NH3 |
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Give the answer to a 6 mark question: Explain why conditions in the Haber process are the way they are |
It is a high pressure because in gaseous reactions like the Haber process, an increase in pressure will favour the reaction that produces the least number of molecules. This means that the higher the pressure, the higher the yield and rate of reaction. A low temperature equals a high yield but a low rate of reaction whereas a high temperature equals a high rate of reaction but a low yield. This means that the temperature of 450 degrees is a compromise between yield, rate of reaction and costs. The iron catalyst further increases rate of reaction which lowers costs and speeds up the process |
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What functional group do alcohols belong to? |
-OH |
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Give three examples of alcohols |
Methanol, ethanol and propanol |
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Give properties of methanol, ethanol and propanol (3) |
Dissolve in water to form neutral solution React with Sodium to produce hydrogen Burn in air |
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Give two uses for all alcohols, and one use for ethanol |
Fuels and solvents Alcoholic drinks |
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What functional group do carboxylic acids belong to? |
-COOH |
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Give three examples of carboxylic acids |
Methanoic acid, ethanoic acid and propanoic acid |
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Give the properties of carboxylic acids |
Dissolve in water to produce acidic conditions React with carbonates to produce CO2 React with alcohols in the presence of an acid catalyst to produce esters Do not ionise completely when dissolved in water so are weak acids |
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What is the property of a weak acid compared to a strong acid |
Higher pH value than aqueous solutions of strong acid with the same concentration |
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What functional group do esters belong to? |
-COO- |
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Give an example of an ester |
Ethyl Ethanoate |
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How is Ethyl Ethanoate produced? |
From ethanol and ethanoic acid in presence of acid catalyst |
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What are the properties of an ester? (2) |
Volatile compounds Distinctive smells |
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Give two uses of esters |
Flavourings Perfumes |
