a) Study the information in the table below and answer the questions that follow. (the letter do not represent the actual symbols of the elements)
(i) What is the general name to the group in which elements P,Q, and R belong?
(ii) What is meant by ionization energy?
iii) Explain why element P have the highest ionization energy.
(iv) When a piece of element Q is placed on water it melts and a hissing sound is produced as it moves on the surface of the water. Explain this observation.
(v) Write an equation for the reaction
between element Q and water.
(b) Distinguish between a strong and a weak base. Give an example of each.
c) Neutralization is one of the methods of preparing salts.
(i) What is meant by neutralization?
(ii) Describe how you would prepare crystals of sodium nitrate starting with
#200cm^3# of 2M sodium hydroxide.
(iii) Write an equation for the reaction that takes place when a solid sample of sodium nitrate is heated.
Answer:
a) i) Alkali metals
ii)Enthalpy change when 1 mole of electron is removed from 1 mole of gases atom.
iii)Its outer electron is close to the nucleus hence held strongly.
iv)-It melts because of the heat produced since the reaction is exothermic.
-the hissing sound is due to the production of hydrogen gas during reaction.
-it moves on the surface due to it being propelled by the hydrogen gas.
v)#2Q_((s))+2H_2O_((l))rightarrow2QOH_((aq))+H_2(g)#
b)A strong base is one which produces high concentration of hydroxide ions(#OH^(-)#)in water e.g sodium hydroxide and potassium hydroxide while a weak base is one which a low concentration of hydroxide ions in water e.g calcium hydroxide.
c)i)Reaction between an acid and acid and base to form a salt and water only.
ii)Add #200cm^3# of 2M nitric(V) acid to #200cm^3# of 2M sodium hydroxide. Heat the mixture to saturation. Allows the mixture to cool for crystals to form.
iii)#2NaNO_3(s)rightarrow2NaNO_2(s)+O_2(g)#
ii)Enthalpy change when 1 mole of electron is removed from 1 mole of gases atom.
iii)Its outer electron is close to the nucleus hence held strongly.
iv)-It melts because of the heat produced since the reaction is exothermic.
-the hissing sound is due to the production of hydrogen gas during reaction.
-it moves on the surface due to it being propelled by the hydrogen gas.
v)#2Q_((s))+2H_2O_((l))rightarrow2QOH_((aq))+H_2(g)#
b)A strong base is one which produces high concentration of hydroxide ions(#OH^(-)#)in water e.g sodium hydroxide and potassium hydroxide while a weak base is one which a low concentration of hydroxide ions in water e.g calcium hydroxide.
c)i)Reaction between an acid and acid and base to form a salt and water only.
ii)Add #200cm^3# of 2M nitric(V) acid to #200cm^3# of 2M sodium hydroxide. Heat the mixture to saturation. Allows the mixture to cool for crystals to form.
iii)#2NaNO_3(s)rightarrow2NaNO_2(s)+O_2(g)#
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in an experiment, soap solution was added to three separate samples of water. The table below shows the volumes of the soap solutions required to form lather with #1000cm^3# of each sample of water before and after boiling.
a) Which water sample is likely to be soft? Explain.
(b) Name the cause of change in the volume of soap solution used in sample III 
