7.2 Water

Out of 100% of water that cover the Earth's surface, only ___ makes up fresh water.

• 97.5%

• 1.97%

• 0.5%

• 2.5%

Kidneys contain about

• 82% water

• 31% water

• 50% water

• 90% water

Water is a universal solvent because it...

• It can be found anywhere
• It freezes when it gets cold
• floats when frozen
• Dissolves most substances

Why is water the most important substance on the planet?

• It Dilutes
• Drives Climate
• Sustains Life
• It's Pretty

The furring of kettles or boilers is as a result of the decomposition of Ca(HCO₃)₂ in hard water into

• NaHCO₃

• NaOH

• CaCl₂

• CaCO₃

The boiling point of water is

Temporary hardness is so called because it is easily removed by

• adding sodium hydroxide

• filtration

• neutralisation

• boiling

Which of the following is water pollutant?

• unburnt hydrocarbon

• pesticides

• ozone

• methane

NaAl₂Si₄O₁₂ is

• zeolite

• sodium alkyl benzene sulphonates

• sodium aluminate

• calcium stearate

Kieserite

• Na₂CO₃.10H₂O

• CaSO₄.2H₂O

• MgSO₄.H₂O

• CaMg(CO₃)₂