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Why is the boiling point of PH3 lower than that of NH3?

PH3 is not hydrogen bonded whereas NH3 is hydrogen bonded. Hydrogen bonding is the strongest type of covalent bonding.
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Answered by Anita T. • Chemistry tutor
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Were Stalin's strengths the main reason why Stalin took control of the Soviet Union in the years 1924-28?

It can be argued to a large extent that Stalin's strengths were the main reason why Stalin took control of the Soviet Union in the years 1924-28. It is also important to consider other relevant factors such ...
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Answered by Rachel O. • History tutor
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Describe how environmental factors affect the growth of roots and shoots in plants. (6 marks)

Plants are able to respond to the environment in multiple ways. Shoots grow upwards, towards light, in a process called phototropism. Roots, on the other hand, grow downwards into the earth towards moisture ...
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Answered by Holly L. • Biology tutor
5055 Views

How can I improve my exam technique?

A common problem amongst Biology students is the difficulty in knowing the content well, but not being able to translate this knowledge into marks when it comes to the exam. Your exam technique is vitally im...
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Answered by Lucy D. • Biology tutor
7366 Views

Derive Keplers 3rd law

Equate gravitational force (GMm/r^2) to centripetal force (mv^2/r). Rearrange to get v^2=GM/r. Due to the approximated circular orbit v=2pir/T so v^2=4pi^2r^2/T^2. Therefore GM/r=4pi^2r^2/T^2. Rearranging gi...
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Answered by Michael S. • Physics tutor
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