Solution and Properties and Applications

What is the concentration of 3 moles of HCl in 3 L of water.

• 1

• 3

• 6

• 9

Answer explanation

Remember the formula:

Mole = Concentration x volume

Hence, concentration = mole / volume

How many liter of water would you need to make a 1 M solution if you have 6 moles of Sodium Hydroxide? 

• 2

• 3

• 4

• 6

Answer explanation

Mole = concentration x volume

Volume = Mole / concentration

A saturated solution is...

• No more solute can be dissolved

• More solute can be dissolved

• The solvent and solution

• Precipitate forms

Answer explanation

Undersaturated - more solute can dissolve in solvent

Saturated - no more solute can dissolve in solvent

Supersaturated - excessive of solute as not all dissolve in the solvent

What change will have least effect on solubility of solid?

• increase in temperature

• decrease in pressure

• increase in surface area

• decrease in temperature

Answer explanation

Remember the 3 main factors of solubility:

1. Intermolecular forces of attraction

2. temperature

3. pressure (applicable to gases)

Which change will decrease the solubility of a gas in water?

• decrease in pressure and decrease in temperature

• decrease in pressure and increase in temperature

• increase in pressure and decrease in temperature

• increase in pressure and increase in temperature

Answer explanation

Think of methane hydrate (methane dissolve in water) - this is applicable with high pressure and low temperature.

This question is in vice-versa. It is asking for decrease in solubility, hence is low pressure and high temperature.

At which temperature would 100 g of liquid water contain the most dissolved nitrogen?

• 20 degree celsius

• 15 degree celsius

• 10 degree celsius

• 5 degree celsius

Answer explanation

Low temperature increase the solubility of gas in solvent

What is the solubility of KCl at 80 degree celsius? (unit: g of salt in 100 g H₂O)

• 20

• 30

• 40

• 50

Answer explanation

Tips:

1. Look the KCl curve.

2. Check the x-axis, look at 80 degree celsius and draw a straight line.

3. The line that touches KCl gives the answer when look at the y-axis.

The ionic compound has solubility of 10 (g of salt in 100 g H₂O) at temperature of 30 degree celsius. What is the ionic compound?

• NaCl

• KClO₃

• CaCl₂

• NaNO₃

Answer explanation

Check the x-axis and y-axis of the given values. Draw straight line to both. The point where the two lines meet falls on KClO₃ curve.

Is KCl solution undersatured, saturated or supersaturated? Given at temperature of 80 degree celsius, 40 g of salt is dissolved in 100 g of H₂O

• Undersaturated

• Saturated

• Supersaturated

Answer explanation

Undersaturated - more solute can dissolve in solvent

Saturated - no more solute can dissolve in solvent

Supersaturated - excessive of solute as not all dissolve in the solvent

Is NaCl solution undersaturated, saturated or supersaturated? Given 40 g of salt dissolved in 100 g of H₂O at 100 degree celsius.

• undersaturated

• saturated

• supersaturated

Answer explanation

Undersaturated - more solute can dissolve in solvent

Saturated - no more solute can dissolve in solvent

Supersaturated - excessive of solute as not all dissolve in the solvent