Exothermic and Endothermic Processes

When a colourless liquid is put on the dry blue cobalt chloride paper, it truns into _____ colour.

Write the test of colourless liquid using cobalt chloride.

Write an equation for combustion of methane.

Carbon dioxide can be detected by the lime water test.

What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(i) The temperature of the solution increases.
(ii) The temperature of the solution decreases.
(iii) The temperature of the solution remains the same.
(iv) Salt formation takes place.

Choose the odd one. Give reasons for your choice.

Carbon dioxide         sunlight                oxygen

Combustion is a slow chemical process.

During the process of respiration heat is absorbed.

Plants make sugar from water and carbon dioxide during photosynthesis.

Leaves carry out _____ to prepare food.

The gas which turns lime water milky is.

Which is the best domestic fuel?

Select the correct answer from A, B, C, D and E for each statement given below:

The basic gas obtained when two gases react in presence of a catalyst & the reaction is exothermic.

[A: Hydrogen B: Copper [II] oxide C: Oxygen D: Copper [II] hydroxide E: Ammonia]

Name the method used for the preparation of the following salts from the list given below.
(i) Sodium nitrate
(ii) Iron (III) chloride
(iii) Lead chloride
(iv) Zinc sulphate
(v) Sodium hydrogen sulphate
List
(A) Simple displacement
(B) Neutralisation
(C) Decomposition by acid
(D) Double decomposition
(E) Direct synthesis

Plants prepare food in the form of simple _____.

Plants produce their own food during the process of _____.

An exothermic reaction is one in which the reacting substances

The formation of the oxide ion ${\mathrm{O}}^{2-}\left(\mathrm{g}\right)$ requires first, an exothermic and then, an endothermic step as shown below:

$\mathrm{O}\left(\mathrm{g}\right)+{\mathrm{e}}^{-}={\mathrm{O}}^{-}\left(\mathrm{g}\right); ∆{\mathrm{H}}^{\mathrm{o}}=-142\mathrm{ }\mathrm{kJ}\mathrm{ }{\mathrm{mol}}^{-1}$

${\mathrm{O}}^{-}\left(\mathrm{g}\right)+{\mathrm{e}}^{-}={\mathrm{O}}^{2-}\left(\mathrm{g}\right),\mathrm{ }∆{\mathrm{H}}^{\mathrm{o}}=844\mathrm{ }\mathrm{kJ}\mathrm{ }{\mathrm{mol}}^{-1}$. This is because