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Chemistry

A Level

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

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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

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What is the easiest way to calculate E cell values?

This is a calculation which students often find tricky. One fail-safe method for doing this calculation is considering E cell = E (reduced) - E(Oxidised). A more positive electrode potential means that a ...

Answered by Rajinder D. • Chemistry tutor

41710 Views

Why does the first ionisation energy increase across period 3?

The 1st ionisation energy is defined as the energy required to remove the outermost electron from one mole of gaseous atoms, forming one mole of gaseous 1+ ions. Moving from left to right the proton numb...

Answered by Hamish P. • Chemistry tutor

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