Write out and complete the following sentences about this separation using words from the list below. condenser higher
crystallisation lower
distillation solid
flask volatile
heavy vapour
Fractional is used to separate a mixture of water and ethanol. The temperature at the top of the fractionating column is than the temperature at the bottom. The more liquid evaporates and moves further up the column. It eventually reaches the where the changes to a liquid.
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[Cambridge IGCSE® Chemistry 0620/21, Question 3(c, d), November 2012]
5
A student placed a crystal of silver nitrate and a crystal of potassium iodide in a dish of water. After an hour she observed that: ◆ the crystals had disappeared ◆ a yellow precipitate had appeared near the middle of the dish. dish of water yellow precipitate crystal of silver nitrate at the start
crystal of potassium iodide
after an hour
Use your knowledge of the kinetic particle theory and reactions between ions to explain these observations.
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[Cambridge IGCSE® Chemistry 0620/21, Question 6(a), November 2012]
6
Vanadium has two isotopes. 50 23
51 23
V
V
a Define the term isotope. b An atom contains protons, electrons and neutrons. Complete the table to show the number of protons, electrons and neutrons in these two isotopes of vanadium. Isotope
Number of protons
50 23
V
Number of electrons
23
[1]
Number of neutrons
23
51 23
V
28
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c Write out and complete these sentences using words from the list. cancer
extra
industry
influenza
medicine
Two types of isotopes are radioactive and are used in for treating patients with
non
-radioactive. Radioactive isotopes .
[Cambridge IGCSE® Chemistry 0620/21, Question 2(a–c), June 2011]
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Cambridge IGCSE Chemistry
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