Chemistry common errors Flashcards
Why is there a lid on containers for chromatography?
To prevent evaporation of solvent
What information does mass spectroscopy give?
Identifies solvents
What will the color of methyl orange indication be when solution turns less acidic?
It will turn from red to yellow
Ammonia + ______ acid = Ammonium nitrate
Nitric
Why do farmers put ammonium nitrate on their farmland?
To help plants grow
Does rate of reaction increases at the start of an experiment?
No
Why is gold used as catalyst in industrial processes?
It increases rate of reaction
It is not used up
Only a small amount of it is needed
Why is the positive electrode in the cell of electrolysis used up?
Because the electrode reacts with oxygen to form carbon dioxide
Why is diamond harder than graphite?
Because the layers of carbon a times in graphite can slide
There is only weak intermolecular forces between layers
However, in diamond, each carbon atom is covalently bonded to 4 others
So no atom is able to slide
Why does graphite conduct electricity but diamond does not?
Graphite has delocalized electrons
Which is a charged particle that moves throughout the structure
However, diamond doesn’t have delocalized electrons
What is the first step of the question: ‘The student wanted to find the volume of HCl that reacts with a known volume of NaOH’?
Measure the volume of NaOH with a graduated pipette
What is the use of silver and carbon in ion change resin?
Carbon removes chlorine (deemed by some to make to water taste better)
Silver kills bacteria in replacement of chlorine
What is the typical unit for bond energy?
Kilojoules
How do you calculate bond energy change?
Bonds broken (energy absorbed) - bonds formed (energy given out)
Why can hydrogen be used as a fuel?
More energy is needed to build bonds than to break them. The reaction is exothermic and energy is released when hydrogen reacts with oxygen in the air
