MEDIUM
Diploma
IMPORTANT
Earn 100

Atom economy is one of the key aspects of green chemistry. Define “atom economy”.

Important Questions on Biochemistry

MEDIUM
Diploma
IMPORTANT

Calculate the atom economy of the following reaction:

4CH3OH + 2CO + O2  2(CH3O)2CO + 2H2O

MEDIUM
Diploma
IMPORTANT

In green chemistry, the use of dangerous materials is generally avoided. Discuss the advantages and disadvantages of using ethanoic acid instead of sulphuric acid as a neutralizing agent for treating alkaline waste.​​​​​​​

HARD
Diploma
IMPORTANT

At pH 7, a solution of alanine contains both the zwitterion and negatively charged (anionic) forms of alanine. Deduce the structural formula of each of these forms.

HARD
Diploma
IMPORTANT

State equations which show the buffer action of the alanine solution when a small amount of strong acid is added and a small amount of strong base is added.

HARD
Diploma
IMPORTANT

An amino acid buffer has been prepared by mixing 0.60 dm3 of 0.20 mol dm3 HCl and 0.40 dm3 of 0.50 mol dm3 glycine solutions. Calculate the pH of the original buffer solution. 

Assume that the densities of all solutions are 1.0 kg dm3 and the volume of the buffer solution does not change when small amounts of strong acid or base are added.

HARD
Diploma
IMPORTANT

An amino acid buffer has been prepared by mixing 0.60 dm3 of 0.20 mol dm3 HCl and 0.40 dm3 of 0.50 mol dm3 glycine solutions. Calculate the pH of the solution after the addition of 1.0 cm3 of 1.0 mol dm3 HCl

Assume that the densities of all solutions are 1.0 kg dm3 and the volume of the buffer solution does not change when small amounts of strong acid or base are added.

HARD
Diploma
IMPORTANT

An amino acid buffer has been prepared by mixing 0.60 dm3 of 0.20 mol dm3 HCl and 0.40 dm3 of 0.50 mol dm3 glycine solutions. Calculate the pH of the solution after the addition of 0.40 g of solid NaOH

Assume that the densities of all solutions are 1.0 kg dm3 and the volume of the buffer solution does not change when small amounts of strong acid or base are added.

MEDIUM
Diploma
IMPORTANT

Compare the behaviour of enzymes and inorganic catalysts, including reference to the mechanism of enzyme action and the ways in which this can be inhibited.