Tag: conservation of water and recycling

Questions Related to conservation of water and recycling

The density of pure water is:

  1. 0.1 g/cm$^{3}$

  2. 1 g/cm$^{3}$

  3. 100 g/cm$^{3}$

  4. 1 kg/cm$^{3}$


Correct Option: B
Explanation:

Density is the ratio of mass per unit volume.
The density of pure water is $1 g / cm^{3}$ or $1000 kg / m^{3}$.

Specific heat of water is:

  1. very low

  2. medium

  3. sometimes high and sometimes low

  4. none of the above


Correct Option: D
Explanation:

The specific heat of water is $1$ $calorie/gm^oC=4.186$ $Joule/gm^oC$, which is higher than another common substance.

So, none of the above statement is true for specific heat of water.

The density of water is:

  1. $1\ g/cm$$^3$

  2. $20\ g/cm$$^3$

  3. $2\ g/cm$$^3$

  4. $0.1\ g/cm$$^3$


Correct Option: A
Explanation:

The density of water is $1 g/cm^{3}$. Density is a ratio of Mass to the Volume. 1 meter long, 1 meter wide, 1 meter high storage tank can store 1,000 kg mass of water. So the density of water is 1. Therefore 1 kg water= 1 litre water(approximately).

Pure water has a pleasant taste.

  1. True

  2. False


Correct Option: B
Explanation:

Pure water is tasteless. As it does not have any impurities(minerals, salts). So, the above statement pure water has a pleasant taste is false.

Water has the maximum density at $ 0^{\circ}C$.

  1. True

  2. False


Correct Option: B
Explanation:

Pure water has maximum density at $4^oC$ when water is heated from $0^oC$ its volume decrease because its density increases and we can see this effect up to $4^oC$.

The boiling point of water is inversely proportional to the atmospheric pressure.

  1. True

  2. False


Correct Option: B
Explanation:

The boiling point of water is not proportional to the atmospheric pressure. As the elevation increases, atmosphere decreases because air is less dense at high altitudes. Because the atmospheric pressure is lower, the vapour pressure of the liquid needs to be lower to reach boiling point. Therefore, less heat is required to make the vapour pressure equal to the atmospheric pressure.

The density of water at  $0^{\circ} C $ is less than the density of water at $ 4^{\circ}C $.

  1. True

  2. False


Correct Option: A
Explanation:

The density of water at $0^oC$ is less than the density of water at $4^oC$. When water is heated from $0^oC$ its volume decreases because its density increase we can see this effect up to $4^oC$, afterward density decreases.

Ice floats over water as its density is less than that of water.

  1. True

  2. False


Correct Option: A
Explanation:

Ice floats over water as its density is about $9\%$ less dense than liquid. The orientation of hydrogen bonds causes molecules to push further apart which lowers its density (cage like structure).

The water pipes burst in cold countries in winter due to anomalous expansion of water.

  1. True

  2. False


Correct Option: A
Explanation:

The water pipes burst in cold countries in winter due to anomalous expansion of water. In cold countries, when temperature falls below $0^{\circ}$C, aquatic life can survive due to anomalous expansion of water. When the temperature of surrounding reaches upto $4^{\circ}$C, the upper surface of the pond will have maximum density and so it sinks to the bottom of the pond.

Distilled water is a good conductor of electricity.

  1. True

  2. False


Correct Option: B
Explanation:

Pure water or distilled water does not conduct electricity. In distilled water there are no impurities, there are no ions, there are only neutral (no charge) water molecules and these neutral molecules do not have charge, So, distilled water does not conduct electricity.

Weight of $1$ $mole$ of hydrogen $=1$ $g$
Weight of $1$ $mole$ of Oxygen $=16$ $g$
Water $=H _2+\cfrac{1}{2}O _2\longrightarrow H _2O$
So, the ratio of mass of Hydrogen to oxygen $=\cfrac{2}{16}=1:8$