Basic questions of chemistry

12 May Basic questions of chemistry

  1. The diagram shows the structures of various compounds.
    (a) Use the letters A to F to answer the following.Each compound may be used once, more than once or not at all.(i) Which one of these compounds is most likely to contribute to acidrain? ………………………………………..(ii) Which one of these compounds is an amphoteric oxide?………………………………………..(iii) Which two of these compounds have giant structures?……………………………… and ………………………………(iv) Which one of these compounds when molten, releases a reddish brown gas at the anode on electrolysis?………………………………………..(b) What is the empirical formula of compound F?

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    (c) Graph 1 shows how the average temperature at the Earth’s surface may have changed over the last 150 thousand years.

    Graph 2 shows how the percentage of carbon dioxide in the atmosphere may have changed over the last 150 thousand years.


    Carbon dioxide is a greenhouse gas. Scientists think that an increase in the greenhouse gases will result in global warming.

     

    (1) Explain how graphs 1 and 2 support this statement.

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    (2) Describe two consequences of global warming.

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    2 .        Helium, neon, argon, krypton and xenon are noble gases.

    (a)        State a use for argon.

     

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    (b)        Use ideas about electronic structure to explain why the noble gases are unreactive.

     

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    (c)        Complete the table to show the number of particles in two isotopes of argon. [1]

    (d)        Explain why potassium comes after argon in the Periodic Table even though it has a relative atomic mass which is lower than that of argon.

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    (e)        Compounds of xenon with fluorine were first made in the 1960s.

    Xenon gas reacts with fluorine gas at 400 °C to form xenon tetrafluoride gas, XeF4. Write a balanced chemical equation, with state symbols, for this reaction.[1]

     

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    They were held horizontally at the same height and then released.

    (f)        Balloons filled with helium, neon, argon and krypton were tied to a bar.The position of three of the balloons 5 seconds after release is shown in the diagram.

     


    Predict the position of the balloon filled with krypton and give a reason of your choice.
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    Did you answer the Secondary Chemistry Tuition Question correctly?

    1.a.i. A/B
    ii. E
    iii. E & C
    iv. C

    b. CH2Br
    c.i. Increase in amount of CO2, increase in earth temp
    ii. Ice melts  sea level rises; cause drought in some areas  plants & animal die of hunger / thirst

    2.a. Light bulb
    b. Full valence electrons, inert as in no electron available to react
    c.

     

    d. Proton of K 19 > Ar 18
    e. Xe (g) + 2F2 (g) à XeF4 (g)
    f. Sink below Ar

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