Experiments
Rates and Equilibria
Energetics
Redox Reaction
Atomic Structure
100
What indicator is colourless in acid, and pink in an alkali?
Phenolphthalein
100
If the concentration of hydrochloric acid is doubled, what happens to the rate of reaction with magnesium?
It doubles.
100
What is an exothermic reaction?
A chemical reaction that releases energy to the surroundings.
100
What is the oxidation number of Cr in K2Cr2O7?
+6
100
Define relative atomic mass
average/mean mass of an atom of an element
relative to 1/12th of an atom of carbon-12
200
Why do we use a polystyrene cup and lid in calorimetry experiments?
To reduce heat loss to the surroundings.
200
Define activation energy
minimum energy
required for a reaction to occur
200
What is the sign of enthalpy change of combustion? positive or negative?
negative
200
What happens to the substance in an oxidation reaction?
its oxidation number increases/ it loses electrons/ it gains oxygen.
200
Write the full electron configuration for calcium.
1s2 2s2 2p6 3s2 3p6 4s2
300
What is a concordant result?
Two titres within 0.10 cm3 of eachother
300
What happens to the Emp on this curve if temperature decreases?
Decreases.
300
Define enthalpy of combustion
enthalpy change of burning 1 mole of a substance
completely in oxygen
under standard conditions
300
Who got oxidized? 2Na + Cl2 = 2NaCl
Na
300
What is wrong with this orbital diagram?
Electron in the third subshell needs to be spin up.
400
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Draw benzene :)
400
How do catalysts increase the rate of the reaction?
Provides an alternative pathway
Lowers the activation energy
400
Define bond enthalpy (energy)
The energy required to break 1 mole of a bond in gaseous state.
400
Is it a redox reaction?
NaHCO3 + CH3COOH = CH3COONa + CO2 + H2O
No
400
Explain how ions are detected in a mass spec.
Ions hit a negative plate, generating current
Current is proportional to abundance.
500
What is used to measure the volume of gas produced in a chemical reaction?
gas syringe
500
Describe dynamic equilibrium
forward rate = backwards rate
closed system
concentration of reactants and products stay constant
500
What is Hess's Law?
The enthalpy change is independent of the path taken
500
Zn + CuCl2 = ZnCl2 + Cu
Which one is oxidising agent?
CuCl2
500
Write the equation for the ionisation of glucose (C6H12O6) using electrospray ionisation.
C6H12O6 (g) + H+ -> C6H13O6 + (g)