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Description
Flashcards by Gabi Germain, updated more than 1 year ago
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Created by Gabi Germain
over 10 years ago
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| Question | Answer |
| What are compounds? | Atoms of two or more elements are chemically combined |
| Which two processes may chemical bonding involve? | Transferring or sharing |
| What does transferring electrons involve? | Lose electrons become positively charged |
| What do ions have the same electronic structure as? | Noble gases |
| What do alkali metals (group 1) react with to form ionic compounds? | Non metal elements |
| What do halogens (group 7) react with to form ionic compounds? | Alkali metals |
| What charge do halide ions have? | A single negative charge |
| What is an ionic compound? | A giant structure of ions |
| How are ionic compounds held together? | By electrostatic forces between oppositely charged ions (forces act in all directions) this is ionic bonding |
| When atoms share pairs of electrons which type of bonding is it? | Covalent bonding |
| What are giant covalent structures known as? | Macromolecules |
| What do metals consist of? | Giant structures of atoms arranged in a regular pattern |
| What happens to the electrons in the highest energy shell of metal atoms? | They are delocalised and are free to move through the whole structure |
| What are there electrostatic forces between? | Positive ions and the delocalised electrons |
| What do metals conduct and why? | Heat and electricity because of the delocalised electrons |
| Why can metals be bent and shaped? | The layers of atoms in metals are able to slide over each other |
| What are alloys? | A metal mixed with one or more other elements |
| What do the different sized atoms do to alloys? | Distorts the layers in the structure so it's difficult to slide over so are harder than normal metals |
| What can shape memory alloys do? | Return to their original shape after being deformed |
| What does nano science refer to? | Structures between 1-100nanometres |
| Why may nano science lead to the development of new catalysts or computers? | They show different properties to the same material in bulk with high SA:V |
| What are thermosetting polymers? | Polymer chains with cross links between them so they don't melt when heated |
| What are thermosoftening polymers? | Consist of individual tangled polymer chains |
| What do the properties of polymers depend on? | What they are made from and the conditions where they are made |
| Hats the difference between high and low density polymers? | High has chains close together |
| What are substances that consist of simple molecules? | Gases, liquids or solids that have relatively low boiling and melting points |
| Why don't simple molecules conduct electricity? | Because they have no overall charge |
| What are the weak forces between simple molecules called? | Intermolecular forces |
| When melted what can ionic compounds do? | Conduct electricity ions free to move |
| In diamond how many carbons are each carbon covalent lay bonded with? | Four so it's very hard |
| In graphite how many carbons is each carbon covalent key bonded with? | 3 |
| Why is graphite soft and slippery? | Because there are no covalent bonds between layers |
| Why can graphite conduct electricity? | One electron from each carbon is delocalised |
| What are fullerenes? | Carbon with different numbers of carbon atoms |
| Want are fullerenes used for? | Drug delivery in the body, lubricants, catalysts and nano particles for reinforcing materials |
| What can atoms that share electrons form? | Giant structures or macromolecules |
| What do macromolecules structures have? | High melting points and strong covalent points |
| What structure do ionic compounds have? | Regular structures with high electrostatic forces in all directions so it takes large amounts of energy to break bonds |
| What are isotopes? | Atoms of the same element that have different numbers of neutrons |
| How can artificial colours be detected? | Paper chromatography |
| What is a mass spectrometer? | Gives the molecular mass of each of the substances separated in the column |
| 3 reasons why the predicted amount if product was not formed? | Because it's reversible, some reactants may react in ways different from expected and products lost when reaction mixture seperated |
| What does gas chromatography do? | Allows the separation of a mixture if compounds which travel through the column at different speeds the output is linked to a mass spectrometer |
| when do chemical reactions occur? | When particles collide with the activation energy needed |
| What are five things that increase the rate of the reaction? | Temperature, concentration, pressure, surface area and catalysts |
| What happens when chemical reactions occur? | Energy is transferred to the surroundings |
| What does an exothermic reaction do? | Transfers energy to the surroundings |
| What does an endothermic reaction do? | It takes in energy from the surroundings |
| If a reversible reaction is exothermic in the forward direction what is it in the backwards direction? | It is endothermic |
| What are two examples of bases? | Metal oxides and hydroxides |
| Salt solutions can be crystallised to produce what? | Solid salts |
| Which ions make a solution acidic? | H+ |
| Which ions make a solution alkaline? | OH- |
| Ammonium dissolves in solution to form what type of solution? | An alkaline solution to produce ammonium salts |
| What can ammonium salts be used for? | fertilisers |
| What three things can acids be reacted with to make salts? | Bases, carbonates and metals |
| What two things does the type of salt produced depend on? | The acid used and the metal in the base or alkali |
| What is another way salts can be formed? | By mixing appropriate solutions of ions so that a precipitate is formed |
| During electrolysis what happens to positive ions? | they move towards the negative electrode and go through reduction |
| What two things can electrolysis be used for? | to electroplate objects and break down a solution into elements |
| What is an electrolyte? | The substance broken down by electrolysis |
| what does the product formed depend on in electrolysis? | Its reactivity |
| What is aluminium manufactured from? | Cryolite and aluminium oxide |
| Where does aluminium form in electrolysis? | at the negative electrode and oxygen at the negative electrode |
| What is the positive electrode made from in aluminium manufacturing? | carbon so CO2 is formed |
| What does the electrolysis of sodium chloride solution produce? | hydrogen and chlorine |
| What can sodium hydroxide be used for? | soap |
| What is chlorine from electrolysis of sodium chloride solution used for? | Bleach and plastics |
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