Available Answers

1. 1.

   Choose the correct answer from the options given below.

   1. Which of the following cycle includes evaporation and condensation?
      1. Oxygen
      2. Nitrogen
      3. Carbon
      4. Water
   2. Which gas is prepared using sodium hydrogen carbonate?
      1. Carbon dioxide
      2. Nitrogen
      3. Carbon monoxide
      4. Water vapour
   3. Which of the following is not a combination reaction?
      1. Reaction between hydrogen and sulphur
      2. Heating hydrogen with chlorine
      3. Heating calcium carbonate
      4. Burning magnesium in air
   4. Which element is a member of the second period and the 13th group of the periodic table?
      1. Boron
      2. Nitrogen
      3. Carbon
      4. Silicon
   5. Which one of the following is charged and cannot exist independently?
      1. Atom
      2. Polyatomic ion
      3. Molecule
      4. Neutron
2. 2.

   Give one word or a phrase for the following statements.

   1. The representation of a chemical reaction using symbols and formulae.
   2. The release of air pollutants into the air.
   3. Elements or compounds that are formed as a result of a chemical reaction.
   4. A mixture of two normally immiscible liquids.
   5. A mixture of solute and solvent.
3. 3.

   Convert the following word equations into the corresponding chemical equation.

   1. hydrogen + chlorine -------► hydrogen chloride
   2. iron(ii) + sulphur ---^heat---► iron (II) sulphide
   3. carbon dioxide + water -------► carbonic acid
   4. water  ---^{electric current}---► hydrogen + oxygen
   5. limestone ^_---heat_---► calcium oxide + carbon dioxide
4. 4.

   Name the following.

   1. A sublime solid
   2. An atom or a group of atoms that has gained or lost electrons
   3. Chemical formula of plaster of Paris
   4. A method to separate ammonium chloride from sand
   5. The outer-most shell of an atom
5. 5.

   Match the columns

   Column A	Column B
   1. SO4 2- 2. Mass number 3. Lustrous non-metal 4. Aerated drinks 5. A metal in combined state	CO2 + H2O ---high pressure---► H2CO3 Mineral Polyatomic ion Total number of protons and neutrons Iodine

6. 6.

   Liquids take the shape of the container. Give a reason.