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Chemistry

A Level

Explain why atomic radius decreases across a period

As you go along a period, there is an increasing number of protons in the nucleus of each atom meaning that the nucleus has an increasing positive charge.This means that the electrons are puller closer to...

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In the reaction CO(g) + 2H2(g) <--> CH3OH(g), explain why an increase in pressure increases the yield of methanol

Increasing the pressure shifts equilibrium towards the side with fewer moles of gas, so in this reaction the equilibrium will move to the right. Hence, a shift towards the right hand side...

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Explain why phenol is nitrated more readily than benzene.

Phenol has a lone pair of electrons on the O group which can be delocalised into the benzene Pi system2) This delocalisation increases the electron density in the pi system compared to benzene3) Thi...

Answered by Daniel B. • Chemistry tutor

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Explain why water molecules form on average two hydrogen bonds per molecule, whereas ammonia molecules (NH3) form only one.

A hydrogen bond requires both a lone pair of electrons on a O, N or F atom and a hydrogen atom. In water there are two lone pairs and two hydrogen atoms, allowing the formation of two hydrogen bonds. In a...

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what is electronegativity and explain the trend in electronegativity as we go down the group?

Electronegativity is the power of an atom to attract electrons in a covalent bond towards itself. As we go down the group, electronegativity decreases because the atomic radii increases. The atomic radii ...

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