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Chemistry

A Level

How to predict the bond angle and shape of a molecule of NH3

An atom of nitrogen has 5 valence electrons in its outer shell. Each hydrogen atom in ammonia bonds to the central nitrogen atom and contributes an electron each. This means there are 8 electrons in total...

Answered by Daidria P. • Chemistry tutor

4536 Views

Back in 1950s, it was common to have as house cleaning items bleaching solution (containing sodium hypochlorite) and ammonia (used to remove, for example, hair dye stains). However, many people ended up in hospital after using them both, why?

Hypochlorite reacts with ammonia to yield chloramine and water. (emphasise to the students that hypochlorite is an oxidising agent, getting reduced to chloride ions). chloramine is a very toxic gas, since...

Answered by Radu B. • Chemistry tutor

2880 Views

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

1738 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

4027 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

10651 Views