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Chemistry

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You have 3.51g of hydrated zinc sulphate. You heat up the zinc sulphate until all the water has evaporated from it. The weight after heating is 1.97g. Find how many H2O molecules per zinc sulphate molecule there are in the hydrated form of it.

Write down the equation: ZnSO4xH2O --> ZnSO4 + xH2O 2. Calculate the masses: 3.51g --> 1.97g + 1.54g 3. Calculate the number of moles, using the molar mass of water and zinc sulphate: 1.97g = ...

Answered by Olivier S. • Chemistry tutor

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What is entropy and how is it used in chemistry?

Entropy (S) is a measure of disorder in a system. Any process, in this case a chemical reaction, is said to entropically favoured if the overall disorder in the system increases. This is usually when ther...

Answered by Kashf S. • Chemistry tutor

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What is the trend in atomic radius of the elements across Period 3 and why does this occur?

The atomic radius of the elements decreases from sodium to argon. This is because the number of protons increases (sodium has 11, argon has 18) so the nuclear charge increases. Therefore, the attraction b...

Answered by Chloe G. • Chemistry tutor

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Explain in detail what do you understand by catalyst, what makes them so useful and give two example of catalytic processes including the name catalyst used.

Catalyst are chemical or biological substances that speeds up the rate of reaction without being used up in the overall process. It provides an alternative route for a reaction occur with a lower activati...

Answered by Priyanka A. • Chemistry tutor

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What is the difference between benzene and cyclohexene?

Benzene, aromatic and unsaturated compound which alternating double bonds. Benzene only reacts with bromine when a catalyst is present. Cyclohexene will react with bromine readily, a saturated molecule wi...

Answered by Imogene B. • Chemistry tutor

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