Search our library of Chemistry A Level questions

Top answers

Chemistry

A Level

Calculate the relative atomic mass of an atom.

You will need to multiply the mass of each isotope (the same atom with a different mass number) by the percentage abundance of that isotope. Then, add all these values together and divide by 100. This wil...

Answered by Emily D. • Chemistry tutor

2111 Views

The equilibrium N2O4 (g) -->--< 2NO2 (g) is set up when N2O4 dissociates. When 0.0370 moles of N2O4 dissociates at 25 degrees in a 0.5dm3 sealed container, 0.0310 moles of N2O4 remains at equilibrium. Calculate the value of Kc for this reaction.

The first step is to formulate the Kc expression. Kc is the "concentration of the products / concentration of the reactants". We show concentration is in moldm^-3 by using square brack...

Answered by Harry M. • Chemistry tutor

4730 Views

What chemical tests are appropriate to identify Butanoic acid, Propanal and 2-methyl propan-2-ol?

Firstly, to identify butanoic acid, adding a small amount of NaHCO₃or any metal carbonates would allow effervescence tobe produced. The effervescence produced is CO₂. To make sure ...

Answered by Athena I. • Chemistry tutor

12301 Views

What type of stereoisomer is shown by butan-2-ol and how can we prove it?

The answer is optical isomerism. Optical isomerism exists when a carbon has 4 different groups attached to it. In Butan-2-ol, the second carbon has a hydroxy group, ethyl group, a methyl group and a hydro...

Answered by Athena I. • Chemistry tutor

12891 Views

The molecular formula of TCDD is C12H4O2Cl4. Chlorine exists as two isotopes 35Cl (75%) and 37Cl (25%). How many molecular ion peaks are there? What is the mass of the most abundant one?

Because chlorine exists as two isotopes, two molecular ions will be present, and their relative heights will correspond to the abundances of the isotopes. The tallest peak will be 3 times the height of th...

Answered by Ana D. • Chemistry tutor

7278 Views