Chemistry Module 3 Flashcards
How does diamond form a giant covalent structure?
Each carbon atom forms 4 covalent bonds
What is diamond used for?
Jewellery and cutting tools
Why does diamond have a high melting point?
Lots of energy needed to break bonds, no free electrons so doesn’t conduct electricity either
What do the carbon atoms in graphite do?
Each carbon atom forms 3 covalent bonds which slide over each other to leave a mark-pencil
Why does graphite have a high melting point?
Lots of energy needed to break covalent bonds
Why does graphite conduct electricity?
3/4 electrons used in bonds, the free electrons conduct electricity
What are the properties of diamond/graphite giant molecular structures
Strong, high melting point, doesn’t dissolve in water, diamond doesn’t conduct electricity, graphite does
What are fullerenes?
Nanoparticles
Give a use of nanotubes
Large surface area so make good industrial catalysts
How do you test water purity?
Chromatography
How can you tell a pure substance?
Can’t be separated by chromatography as they have specific boiling/melting points
How can you tell an impure substance?
Melting point is too low, boiling point too high
Explain batch production and its advantages and disadvantages
Batch production only happens at certain times, cost effective as start up costs are low, labour intensive and hard to keep the quality
Explain continuous production and its advantages and disadvantages
Continuous production always runs- for Large scale manufacture ie Haber process, no time wasted as its automatic, consistent quality, huge start up costs, not cost effective to run at less than full power
Why are pharmaceutical drugs expensive?
Research and development, trialling, manufacture-materials-extract from plants
What is the equation for atom economy?
Total Mr of desired products divided by the total Mr of all products x 100
What is atom economy?
% of reactants changed to useful products
What does percentage yield compare?
Actual and predicted yield
What is the equation for percentage yield
Actual yield (g) divided by predicted yield (g) x 100
What does 0% percentage yield mean?
No product made
How is reactant lost?
Evaporation, filtration, transfer of liquids, not all reacts
What is an ionic bond?
When a + ion is attracted to a - ion and they join
What is the formula for hydrochloric acid?
HCl
What is the formula for calcium chloride?
CaCl2
What is the formula for calcium carbonate?
CaCO3
What is the formula for sulphuric acid?
H2SO4
What is the formula for magnesium sulphate?
MgSO4
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1 gram of water by 1 degree
What is the specific heat capacity of water?
4.2 j/g/ degrees c
What is the calorimetric method?
Put fuel in a spirit burner, weigh, measure water into a copper calorimeter, take temperature, put burner under calorimeter, light the wick, when the water temperature has risen by 20-30 degrees, blow out the wick and note the highest temperature of water.
What is the equation of energy given out per gram?
Energy released (j) divided by mass of fuel burned (g)
What is the equation for energy transferred?
Energy transferred= mass of water x shc of water x temp change
What is an exothermic reaction?
A reaction which gives out energy to the surroundings usually heat shown by a rise in temp
What is an endothermic reaction?
One which takes in energy from the surroundings usually heat shown by a fall in temp
How do you measure the amount of energy used?
Take the temp of reactants, mixing them and taking the temperature again
Give an example of an exothermic reaction
Adding acid to alkali
Give an example of am endothermic reaction
Dissolving ammonium nitrate
What kind of reaction is bond breaking?
Endothermic
What kind of reaction is bond making?
Exothermic
What happens to the mass in a chemical reaction?
Mass is conserved, no atoms are lost or gained
