Water quality 1

As gas partial pressure increases, gas solubility in water:

• Does not change

• Increases

• Decreases

• Temperatura does not affect gas solubility en water

As temperature decreases, gas solubility in water:

• Decreases

• Increases

• Temperature does not affect gas solubility

• Increases or decreases, depends on the type of gas

As temperature increases, solids solubility in water:

• Always decreases

• Always increases

• Can increase or decrease, it depends on the type of solid

• Temperature does not affect solids solubility

Which of the following units are used to express turbidity in water

• mg CaCO₃/L

• mg Ca⁺⁺/L

• NTU

• Pt-Co

Which of the following elements / compounds increases water alkalinity?

• SO₄^2-

• HCO₃^-

• H⁺

• OH⁺

Which of the following give hardness to water?

• Na⁺

• H⁺

• HCO₃^-

  CO₃^2-

  OH^-

• Ca⁺⁺

  Mg⁺⁺

Select the wrong answer.

Permanent hardness...

• ...can be reduced by boiling the water

• ...can be reduced by ion exchange softening

• ...implies that a higher amount of soap and detergents is needed for cleaning.

• ...creates difficulties at cooking some vegetables.