stuff to know

Question 1

Is it necessary to add sulfuric acid during the oxidation of alcohols

Answer 1

yes because acidified potassium dichromate is used as an oxidising agent

Question 2

After forming a carboxylic acid under reflux, why does it have to be distilled further?

Answer 2

at the top of the reflux column, there still is some acidified potassium dichromate so needs to be distilled

Question 3

Why do hydrogen atoms not appear in an electron density map produced by X-ray diffraction?

Answer 3

they have low electron density

Question 4

Explain the convergence of lines in a hydrogen emission spectrum

Answer 4

energy levels are closer together at higher energy

Question 5

How does changing concentration affect electrode potential?

Answer 5

Changes in temperature, pressure or concentration will effectively change the position of the redox equilibrium and hence the electrode potential of the half-cell. If the position of equilibrium is shifted in favour of the reduction reaction, the electrode potential becomes more positive and cell potential increases

Question 6

Explain the presence and relative abundance of multiple peaks on the mass spectrometry

Answer 6

• represents the isotopes of element
• the molecule is diatomic so the largest peak represents both elements
• the last peak is the least abundant

Question 7

Equipment to measure volume in titrations

Answer 7

• graduated pippette
• volumetric pipette
• burette