- Write the balanced chemical equation for the following reaction and identify the type of reaction and define it. ‘Iron III oxide reacts with Aluminium and gives molten iron and aluminium oxide’.
- Name the following :
(a) A metal which is preserved in
kerosene
(b) A lustrous coloured non metal
(c) A metal which can melt while kept on
palm.
(d) A metal, which is a poor conductor of
heat.
3.
A reddish brown coloured metal, used in electrical wires, when powdered
and heated strongly in an
open china dish, its colour turns black.
When hydrogen gas is passed over this black substance, it regains its
original colour. Based on the above
information answer the following questions.
(i) Name the metal and the black
coloured substance formed.
(ii) Write balanced chemical
equations for both the reactions.
4. (a) Give an example for a combination
reaction which is exothermic.
(b) Name the phenomenon due to
which the taste and smell of oily food changes when kept for a long time in open. Suggest one method to prevent it.
5.
(a) Write the name given to bases
that are highly soluble in water ? Give
an example.
(b) How is tooth decay related to
pH ? How can it be prevented ?
(c) Why does bee sting cause pain and
irritation ? Rubbing of baking soda on
the sting area gives relief. How ?
6. (a) Why is calcium starts floating when
added to water ?
(b) Most
of the metals do not give hydrogen while reacting with nitric acid.Why ?
(c) Write equation for the reaction of iron
with steam. Name the compound of iron obtained.
7.
Identify the type of chemical reaction
and also write the chemical equation for the reaction that takes place
when a solution of potassium chloride is mixed with silver nitrate
solution. Write the chemical name of one
of the products obtained.
8.
What is rancidity? Mention any two ways by which rancidity can be prevented
?
9.
Differentiate between strong and weak acids. Identify the strong and weak acids from the
following list of acids. Hydrochloric acid, acetic acid, formic acid, nitric
acid.
10.
Write two observations that you will make when an iron nail is kept in
an aqueous solution of copper sulphate ? Write the chemical equation for this
reaction.
11.
A current carrying conductor produces a magnetic field around it. Is
there a similar magnetic field produced around a thin beam of moving
(i)
electrons
(ii)
neutrons. Justify your answer.
12. Write balanced chemical equation for the
reactions that take place during respiration. Identify the type of combination
reaction that takes place during this
process and justify the name. Give one more example of this type of reaction.
13.
A compound which is prepared from gypsum, has the property of hardening
when mixed with right quantity of water.
(i)
Identify the compound and write its chemical formula.
(ii) Write
the chemical equation for its preparation.
(iii)
List any two uses of the above compound.
14. Give
reasons for the following :
(i) Ionic
compounds have high melting point and boiling point.
(ii)
Ionic compounds conduct electricity in molten state.
(iii)
Ionic compounds are solids at room temperature and are somewhat hard.
- How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle ? Why the same process cannot be applied for them ?Explain giving equations, the extraction of sodium.
