4481348
Description
Flashcards by christianwalker1, updated more than 1 year ago
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Created by christianwalker1
about 10 years ago
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| Question | Answer |
| What are shape memory alloys? | Alloys which can return to its original shape after being deformed |
| why do metals conduct electricity? | they have delocalised electrons in their structure |
| what can fullerenes be used for? | drug delivery in the body, catalysts, nanotubes |
| what are the bonds like in thermosetting? | crosslinked so they do not melt when heated |
| what are the bonds like in thermo-softening? | individual tangled polymer chains |
| what do catalysts do? | speeds up a reaction and lowers cost |
| how does graphite conduct electricity? | one electron from each carbon atom is delocalised |
| what are the properties of graphite? | each carbon atom is linked to 3 other carbons, soft and slippery with no covalent bonds |
| what are the properties of diamond? | each carbon is linked to 4 others making it hard, giant structure, strong covalent bonds, high melting point |
| what are the properties of covalent compounds? | low melting points, low boiling points, gas/liquid at room temp, does not conduct electricity |
| why are covalent compounds liquid/gas at room temperature? | weak intermolecular forcess, can be overcome by small amounts of energy |
| what are isotopes? | atoms with different numbers of neutrons, same number of protons |
| what does gas chromatography do? | separates mixtures in a column |
| what are the advantages of gas chromatography? | fast sensitive accurate |
| what is an alloy and why is it hard? | made of 2 or more metals, molecules of different shapes distort layers |
| what happens during an endothermic reaction? | takes in energy from the surroundings, temperature falls |
| what happens during an exothermic reaction? | transfers energy to the surroundings, temperature rises |
| what does simple chromatography do? | used to indentify additives in foods |
| what is the pH of acids and alkalis? | acids 1-6 allalis 8-14 |
| what happens at the positive and negative electrode in electrolysis? | positive- attracts negative ions, loses electrons (oxidation) negative-attracts positive ions, gains electrons (reduction) |
| what are the masses and charges of protons, neutrons and electrons? | proton 1__ + neutron 1__0 electron v small__- |
| what is a precipitate and how can it be removed? | insoluble solid, filtration |
| what is the neutralisation equation? | OH- + H+ ---> H2O |
| how is an ionic compound formed? | metals lose electrons, become positive, non metals gain electrons, electrostatic attraction |
| what do catalysts do? | speed up a reaction and reduce costs |
| what are the bonds like in thermo-softening? | individual tangled polymer chains |
| what are the bonds like in thermo-setting? | cross-linked |
| how does surface are effect a reaction? | more surface area for reactants, more frequent collisions |
| how does pressure effect reaction? | less space for particles, more frequent collisions |
| how does increasing concentration effect reactions? | more particles, more frequent collisions |
| what does the mass spectrometer do? | identifies the substance, gives the Mr |
| how can the rate of reaction be increased? | temperature, concentration, pressure, catalysts, surface area |
| how does temperature effect rate of reaction? | increases speed of particles, more frequent collisions |
| how does a metal atom become an ion? | loses/transfers outer electron, becomes positive |
| how does a non- metal atom become an ion? | gains electrons, becomes negative |
| why are metal ions attracted to non-metal ions? | oppositely charged ions are attracted, metals are positive, non metals are negative |
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