C456 OCR Twenty-First Century

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  • Created by: Tami
  • Created on: 12-11-16 12:13
How did Mendeleev arrange his periodic table?
He arranged them into GROUPS (Vertical periods) and PERIODS (horizontal rows).He arranged them based on their relative atomic masses and patterns in their properties.Mendeleev left gaps for undiscovered elements and predicted their properties.
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How did Döbereiner arrange his periodic table? Why was his periodic table rejected?
He arranged them into triads that linked patterns of the relative atomic masses of three elements. The first and last element had a mean average of the middle element.This was rejected because most elements did not fit this pattern.
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How did Newlands arrange his periodic table? Why was his period table rejected?
Newlands noticed 'octaves' patterns that every eighth pattern had similar properties.This was rejected because most elements did not fit this pattern.
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What is the charge and mass of a proton?
It has a positive charge (+) and a mass of 1
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What is the charge and mass of an electron?
It has a negative charge (-) and a mass of almost zero (negligible).
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What is the charge and mass of a neuron?
It has a no charge and a mass of 1.
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What is the formula of relative atomic mass?
Number of protons + number of neurons--> relative atomic mass
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How many electrons does the first shell/energy level hold? How many do the shells/energy levels after the first one hold?
The first shell holds 2 electrons. The shells after hold 8 electrons
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In a periodic table, what does a group show?
The different groups show how many electrons in the outer shell.
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In a periodic table, what does a period show?
The different groups show how many shells an element has.
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What is Group 1? and what is the trend in that groups?
Alkali metals are soft metals that have shiny surfaces when cut but tarnish easily.They increase reactivity as they go down the group.
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Why do group 1 alkali metals increase reactivity as they go down?
The outer electron is easier to lose as the atom gets bigger, because the outer electron is further away from the nucleus, this means there is more shielding due to more shells in bigger atoms.This means they have less attraction forces.
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What is the equation for a group 1 alkali metal and water?
metal+water-->metal hydroxide + hydrogen
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What is the equation of a group 1 alkali metal and chlorine?
metal+chlorine-->metal chloride
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How do you test for an alkali?
Universal Indicator. The PH of alkalis is above 7, it has the colour purple and blue.
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What are Group 7 elements called and what is the trend in the group?
Group 7 are called halogens.They reduce reactivity as they go up the group.
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Why do Group 7 elements decrease reactivity as they go down the group?
Group 7 elements decreases down the group because, as you go down the group: The atoms get larger. The outer shell gets further from the nucleus (more shells) Attraction between the nucleus and electrons gets weaker,an electron is less easily gained.
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When Group 1 alkali metals (or any metal) react with group 7 halogens what do they produce?
Metal halides
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What is a displacement reaction and when does it take place?
A displacement reaction is when a more reactive halogen takes the place of a less reactive halogen in a compound. E.G potassium bromide + chlorine --> potassium chloride + bromine
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What are ionic compounds?
Charged particles/ions arranged in a regular pattern called a crystal lattice.
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Properties of ionic compounds?
They are salts that are soluble in compounds. When they are melted or dissolved they conduct electricity.They have high melting and boiling points.
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Why can't ionic compounds conduct electricity in solids?
They cant conduct electricity as solids because the ions are unable to move in a lattice.
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What happens to ionic compounds in electrolysis?
The positive ions moves to negative electrode and gain electrons to become atoms. While negative ions go to the positive electrode and they lose electrons to become atoms.
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Hydrosphere definition
All the water on the earth including oceans, seas, lakes and rivers
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What is an ionic bond?
The strong force of attraction between positively charged and negatively charged ions.
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What is a lithosphere?
The rigid outer layer of the Earth made up of crust and upper mantle.It contains rocks and minerals
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What are minerals?
solids with atoms or ions arranged in a regular arrangement or lattice.
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What is reduction?
When something loses oxygen
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What is oxidation?
When something gains oxygen
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What are ores?
Rocks that contain metal minerals.
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How can copper oxide be extracted from its ore?
They can be extracted by heating them with carbon E.G (Copper Oxide+Carbon-> Copper+Carbon dioxide)
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What is a redox reaction?
When both oxidation and reduction both take place in a reaction.
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What is a giant covalent structure (give examples)?
A covalent structure with many covalent bonds in a regular pattern. E.g Diamond and graphite contain many carbon atoms covalently bonded in a giant covalent structure.
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What are small covalent molecules (give examples)?
These contain only a few atoms held together by strong covalent bonds between atoms. An example is carbon dioxide (CO2). However the inter-molecular forces between the atoms are weak (2CO2 can easily break into CO2)
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Describe the properties of diamonds?
Each carbon atom is covalently bonded to four other carbon atoms in tetrahedral 3-D lattice.It has a giant covalent structure. High Melting and boiling points. Doesn't dissolve in water or conduct electricity.
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Describe the properties of graphite?
Each carbon atom is covalently bonded to three others in sheets (strong). The forces between the layers are weak and this allows the layers to slide over each other.There are free electrons in graphite allowing it to conduct electricity
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What is relative atomic mass?
The mass of an atom compared to the mass of carbon which is given the value 12
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What is relative formula mass of a compound?
The sum of the relative atomic masses of all atoms or ions in its formula. E.G H2O= (2x1)+16=18
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What is gram formula mass?
The relative atomic mass or relative formula mass in grams (g)
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What is the formula to find out the percentage of metal in a mineral?
percentage of metal in mineral = (total mass of metal atoms ÷ gram formula mass) x 100
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What is electrolysis?
Passing an electric current through an ionic compound when it is molten of dissolved in liquid
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What is an electrolyte?
An ionic compound is called the electrolyte because it can conduct electricity
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What happens to electrolytes as electricity passes through them?
The electrolytes break down/ decompose as the electricity passes through it.
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What can't aluminium be extracted from aluminium oxide using carbon?
Electrolysis is used to extract more reactive metals (like aluminium) because their oxides cannot b reduced by carbon.
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What happens to Cl- during electrolysis?
Cl- moves to the positive electrode (anode) and then it loses an electron to form a neutral Cl atom
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Properties of metals
They are malleable,strong, have high melting points and are good conductors of electricity.The atoms are held together by metallic bonds in a giant lattice.Metallic bonds are strong (lots of energy needed to melt and reshape metals)
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Why do metals conduct electricity?
Metal atoms lose their outer shell electrons to for positive ions in solid metal.The outer shell electrons form a sea of free electrons that can carry a current.
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Why are pure metals malleable?
All the atoms are the same and they can roll over each other. This means that metals can be reshaped even though they have strong metallic bonds.
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Give examples of three poisonous metals?
Lead, mercury and cadmium.
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What are the faults with processing rocks to produce metals like copper?
-Large amounts of rocks need to be processed to produce small quantities of metal. -Processing large amounts of rock uses a lot of energy
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What is copper used for ?
electrical wiring, circuits,pipes and building materials
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Faults with the extraction of metals?
Some minerals contain compounds of metals with sulfur.During extraction of metals sulfur dioxide is made.Sulfur dioxide produces acid rain and damages plants and fish.
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What is chemical synthesis (give examples of its uses)?
Using simple substances to make new, useful chemical compounds.E.g for food additives, fertilisers, dyes, paints, pigments and medicines
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What colour does an alkali turn when univeral indicator is added and What PH are alkalis?
Alkalis turn blue when universal indicator is added, they have a PH above 7
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What colour does an acid turn when universal indicator is added and what PH is an acid?
Acids turn red when universal indicator is added and they have a PH less than 7
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Word equation for acid reacting with metal?
metal + acid --> salt + hydrogen (Calcium+ hydrochloric acid --> calcium chloride + hydrogen)
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Word equation for acid reacting with metal oxide/metal hydroxide?
metal oxide/hydroxide + acid --> salt + water (magnesium oxide + sulfuric acid --> magnesium sulfate + water)(Sodium hydroxide + nitric acid --> sodium nitrate + water)
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Word equation for reacting a metal carbonate with an acid?
metal carbonate + acid --> salt+ water+carbon dioxide (calcium carbonate + hydrochloric acid--> calcium chloride + water+carbon dioxide)
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What is a titration?
It is used to measure the volume of acid and alkali that exactly react together. An indicator is added so you can see when neutralisation takes place, the indicator changes colour at the end-point of the titration.
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What is the process called when an acid reacts with an alkali.
neutralisation
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Word equation for neautralisation?
acid+ alkali--> salt + water
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What is an endothermic reaction?
A reaction in which heat energy is taken in. The reactants have less energy than the products.(The temperature of surrounding falls)
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What is an exothermic reaction?
A reaction that gives out heat energy. The reactants have more energy than the products. (The temperature of surrounding rises)
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Formula of percentage yield
Percentage yield =actual yield ÷ theoretical yield x 100
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What is the rate of reaction?
The amount of a product produced or the amount of reactant used up.
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What increases rate of reaction?
Temperature increase , high concentration of reactants in solution, small particle size (if they are small they have a bigger surface area) and catalyst
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What is a catalyst?
A substance that speeds up a chemical reaction but is not used up. It provides area for the reaction to take place on.
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What must happen for a reaction to take place?
Particles must collide. The most collisions that happen, the faster the reaction.
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Other cards in this set

Card 2

Front

How did Döbereiner arrange his periodic table? Why was his periodic table rejected?

Back

He arranged them into triads that linked patterns of the relative atomic masses of three elements. The first and last element had a mean average of the middle element.This was rejected because most elements did not fit this pattern.

Card 3

Front

How did Newlands arrange his periodic table? Why was his period table rejected?

Back

Preview of the front of card 3

Card 4

Front

What is the charge and mass of a proton?

Back

Preview of the front of card 4

Card 5

Front

What is the charge and mass of an electron?

Back

Preview of the front of card 5
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