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90 Cards in this Set
- Front
- Back
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What are ions?
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Electrically charged particles
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How are ions formed?
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When atoms loose or gain electrons
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The structure of ions are similar to what?
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Noble gases
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What sort of ions do metals form?
Non-metals? |
Positive (loss of electrons)
Negative (gain of electrons) |
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What holds ions together?
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The strong electrostatic forces of attraction between oppositely charged ions (ionic bond)
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What type of metals are found in Group 1?
What is found in Group 7? |
Alkali metals
Halogens |
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What are involved with an ionic bond?
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Metal and Non- Metal
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What are involved in a covalent bond?
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Non-Metals
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What do covalent bonds form?
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Molecules
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What holds an ionic lattice together?
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Strong electrostatic forces of attraction between oppositely charged ions
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When do ionic compounds conduct electricity?
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Molten or in a solution
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What is a mixture?
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Two or more elements/compounds that aren't chemically bonded, properties remain unchanged
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What is a compound?
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Two or more elements chemically bonded together, arrangement of outer shell changes
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What are the properties of simple molecular compounds?
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Low melting and boiling points due to strong covalent bonds but weak intermolecular forces
No overall charge so they can't conduct electricity |
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What is the term for giant covalent structures?
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Macromolecules
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Give 3 examples of giant covalent structures
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Diamond
Graphite Silicon Dioxide |
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What are the properties of a covalent bond?
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Low melting and boiling points due to the fact that they form molecules with strong covalent bonds but weak intermolecular forces of attraction
Insoluble in water Don't conduct electricity |
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What are diamond and graphite examples of?
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Allotropes, in this case carbon
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What are fullerenes?
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Hexagonal rings of carbon atoms
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What is an example of a fullerene?
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Buckminsterfullerene
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What are the properties of graphite?
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Soft and slippery due to the fact that graphite is arranged in layers
Conducts electricity because only 3 electrons are used to bond the carbon atoms together, leaving a delocalised electron to carry the current |
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Why can metals conduct electricity?
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Electrons in outer shell become delocalised because the atoms are so tightly packed so the layers overlap
This creates regular lattice of positive ions held together by electrons by electrostatic attraction |
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Why are alloys stronger than pure metals?
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Because the mixture of different shaped atoms disturbs the regular arrangement of layers meaning the layers can't slide
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Name some uses of shape memory alloys
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Dental braces
Spectacle frames |
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Name an example of a shape memory alloy
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Nitinol
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What varies the properties of polymers?
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What monomer was used to make the polymer
The catalyst used The temperature under which it was made |
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Why are LDPE and HDPE different?
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Different catalysts were used
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What does a thermo-softening polymer consist of?
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Individual polymer chains that are tangled together
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What are the properties of thermo-softening polymers?
Why do they have these properties? |
Can be softened and shaped when heated
Weak intermolecular forces between each polymer chain |
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What are isotopes?
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Elements that are the same but have a different number of neutrons
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How small is a nanometre?
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1 billionth of a metre
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What are diamond and graphite made from?
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Carbon atoms
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How is diamond structured?
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In a giant covalent structure
A lattice shaped like a pyramid |
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How many bonds does 1 carbon atom form to other carbon atoms in diamond?
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4
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Why is diamond such a hard substance?
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Due to the large number of strong covalent bonds
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How is graphite structured?
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In a giant covalent structure
Arranged in layers |
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How many bonds does 1 carbon form with other carbon atoms in graphite?
What does this mean? |
3
1 delocalised electron for every carbon atom which are free to move through the layers, creating an electric current |
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What properties does a layered structure create in graphite?
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The layers can slide over each other resulting in a soft and slippery substance that can be used as a lubricant
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What are the layers held together by in graphite?
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Weak intermolecular forces of attraction
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How are metals arranged?
What properties are created by this? |
Layers, regular lattice of positive ions held together by strong electrostatic forces of attraction
Malleable materials that can be bent and shaped |
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What are shape memory alloys?
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They are alloys that respond to changes in the environment and remember their shape
They can be deformed but will return to their original shape |
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What are the properties of thermo-setting plastics?
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Polymer chains joined by cross links
They don't melt |
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What is created when nanoparticles combine?
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Nanostructures
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What is nanoscience?
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The study of very small structures
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Why are the properties of nanoparticles different to the same material in bulk?
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Nanoparticles are more sensitive to light, heat and magnetism
Have a higher surface area compared to their volume |
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The research of nanoparticles may lead to what?
Name 6 |
New catalysts
New computers New coatings New highly selective sensors Stronger and lighter construction materials Cosmetics e.g sun creams and deodorants |
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What are fullerenes used for?
Name 4 |
Deliver drugs in the body
Lubricants Catalysts Nanotubes (reinforce materials) |
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What is the relative formula mass?
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Total mass of a compound
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How do you calculate the percentage mass?
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Relative mass of element in compound
_________________________________________ x100 Relative formula mass of compound |
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What is the empirical formula?
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Simplest whole number ratio of each kind of atom
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What is a mole?
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Number of particles (atoms or molecules) in a substance
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What is 1 mole equal to?
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The relative formula mass
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How big is a mole?
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6x10^23
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How do you calculate the number of moles in a substance?
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Mass of substance
_________________________ Mass of one mole (RAM) |
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What is chromatography used for?
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Identify substances within an unknown substance
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What are the steps of chromatography?
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1. Sample of unknown substance is placed on the start line of a piece of paper
2. Paper dipped in solvent 3. Solvent dissolves the sample and carries the substances contained in the sample up the paper. The position of the substances on the paper identifies what it is 4. The paper is then compared with known substances to identify what was within the unknown substance |
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What is the yield?
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Amount of product obtained
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Why is it not possible to obtain the maximum amount of product?
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If reaction is reversible it might go to completion
Some product could be lost when separated from reaction mixture Reactants may act differently to what was expected Some of the product may stick to the apparatus |
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How do you calculate the percentage yield?
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Yield from Reaction
_________________________ x100 Maximum yield possible |
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What factors affect the rate of reaction?
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Use of catalyst
Surface Area Concentration Temperature |
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How do you calculate the rate of reaction?
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Amount of reactants used/product formed
_____________________________________________ Time |
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What is an exothermic reaction?
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Temperature rise
Transfers heat energy to the surroundings |
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Give some examples of an exothermic reaction
Name 3 |
Neutralising alkalis with acids
Oxidation Combustion |
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What products use exothermic reactions?
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Hand warmers
Self-heating cans |
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What is an endothermic reaction?
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Fall in temperature
Heat is taken from surroundings |
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Give examples of an endothermic reaction
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Thermal decompostition
Electrolysis |
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What products use endothermic reactions?
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Instant sports injury ice packs
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What does a mass spectrometer measure?
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Relative molecular mass
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What does a catalyst do?
Name 4 |
Reduces amount of energy needed for successful collision (activation energy)
Makes more collisions successful Speeds up reaction Provides surface for molecules to attach to, increasing chance of collisions |
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Why is surface area important in terms of the rate of reaction?
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Smaller pieces have a larger surface area in comparison to their volume
More particles are exposed and available for collisions which means a faster reaction |
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What is an alkali?
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Bases dissolved in water
Soluble base |
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What colour do alkalis turn red litmus paper?
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Blue
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What colour do acids turn blue litmus paper?
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Red
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When an acid is dissolved in water, what's produced?
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Hydrogen ions (H+)
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When an alkali is dissolved in water, what's produced?
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Hydroxide ions (OH-)
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What is produced when hydrogen and hydroxide ions react?
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Water
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Acid + Metal Oxide=?
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Salt + Water
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Acid + Metal Hydroxide=?
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Salt + Water
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Acid + Metal=?
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Salt + Hydrogen
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How can you predict the name of the salt produced in a neutralisation reaction?
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The first part of the name is always the first part of the base
The second part of the name is related to the first part of the acid e.g Hydrochloric Acid + Copper Oxide = Copper Chloride |
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What is ammonia?
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An alkaline gas
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What industry is it used in?
Why? |
Production of fertilisers
Increases nitrogen content |
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Ammonia neutralises nitric acid to produce what?
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Ammonium nitrate- This is used in fertilisers
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Why are nitrogen based fertilisers so important?
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Increases the yield of crops
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What problems can nitrates cause?
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Upset the natural balance of water
Contaminate drinking water |
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What is electrolysis?
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Breaking down of a compound containing ions into its elements using an electrical current
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What is the substance called which is broken down in electrolysis?
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Electrolyte
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What is a redox reaction?
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Where both reduction and oxidation reactions occur
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What is a reduction reaction?
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When positively charged ions gain electrons at the negative electrode
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What is an oxidation reaction?
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When negatively charged ions lose electrons at the positive electrode
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