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Chemistry

A Level

Why is the first ionisation energy of Potassium less than Sodium?

The first ionisation energy is the energy required to move one mole of electrons from one mole of atoms in its gaseous state.
The outer electron in Potassium is in the 4s orbital, which is further aw...

Answered by Abida R. • Chemistry tutor

25917 Views

Calculate the mass, in grams, of CH3CH2NH2 produced from 32.9 g of CH3CH2I reacting with an excess of NH3 assuming a 70.0% yield.

To tackle any question like this, you should first write out the reaction formula (I would do this on the whiteboard). You can see from this that the ratio between the reactant and product is 1:1. You can...

Answered by Rob B. • Chemistry tutor

3642 Views

Calculate the pH of the following solutions: 0.002 mol/dm^-3 KOH

pH by definition is given as -log₁₀(c_H+) or log₁₀(1/c_H+), where c_H+ is the concentration of the H+ ions in the solution.Similarly, pOH= -log₁₀

Answered by Csaba B. • Chemistry tutor

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Why do transition metals form coloured compounds?

Transition elements have 3d orbitals with the same energy level however when molecules/ligands form dative covalent bonds with a metal ion, the electron repulsion causes the 3d orbitals to split into lowe...

Answered by Chiamaka C. • Chemistry tutor

28973 Views

Identify which 2 of the following processes involve an exothermic change: melting, boiling, freezing, deposition and sublimation

An exothermic reaction involves an output of heat, so heat is lost overall. This would mean that boiling and melting are definitely not exothermic as they involving putting in heat. Free...

Answered by Ellen S. • Chemistry tutor

5237 Views