Chemistry 溫習題目 2
The following table gives some information on three metals P, Q and R and their oxides.
Metal / P / Q / R
Method of storage / Under paraffin oil / In an air-tight container / In a safe container
Colour of metal oxide / White / White / Red
a) Oxides of P and Q give a golden yellow and a brick-red flame in the flame test respectively.
(i) Describe the steps of carrying out the flame test.
(ii) Suggest what P and Q might be.
b) Explain why P has to be stored under paraffin oil.
c) (i) Describe the observations when P is added to cold water.
(ii) Is the resultant solution acidic or alkaline? What is the colour change of the red litmus paper if it is dipped into the solution?
d) A colourless gas forms when Q is added to dilute hydrochloric acid.
(i) Draw a labelled diagram to show how the gas can be collected.
(ii) Suggest a test for the gas and state the positive result.
e) R reacts with oxygen on very strong heating.
(i) Suggest what R might be.
(ii) State ONE use of R.
f) Arrange P, Q, and R in decreasing order of reactivity.
g) Suggest the methods of extraction for P, Q, and R from their metal oxides.
- polarbearhmhLv 46 年前最愛解答
1) Moisten a clean platinum/nichrome wire with concentrated hydrochloric acid.
2) Dip the wire into a crushed sample.
3) Heat the end of the wire strongly with a non-luminous flame.
b) P reacts with air readily.
1) P melts to form a silvery ball.
2) It moves quickly on the water surface with a hissing sound.
3) It burns with a golden yellow flame.
The resultant solution is alkaline. Red litmus paper turns from red to blue.
(ii) Test the gas with a burning splint. Hydrogen gas burns with a pop sound.
(ii) Make thermometers.
f) P, Q, R
P: electrolysis of molten metal oxide
Q: electrolysis of molten metal oxide
R: direct heating