Topic 2.2 - Water

Where do hydrogen bonds form?

• Between the slight negative charge of hydrogen and slight positive charge of oxygen within a water molecule

• Between the slight positive charge of hydrogen and slight negative charge of oxygen within a water molecule

• Between the slight positive charge of hydrogen and slight negative charge of oxygen in different water molecules

• Between the slight negative charge of hydrogen and slight positive charge of oxygen in different water molecules

Researchers have developed a skin patch which can detect and measure very small concentrations of ions, sugars, amino acids, proteins and hormones which remain when sweat evaporates. What allows the presence of these substances in sweat?

• Cohesion

• Hydrophobic interactions

• Solvent properties

• Thermal properties

Which property of water accounts for its moderating effects on the Earth’s climate?

• Cohesive

• Thermal

• Transparency

• Adhesive

Which can be explained by the solvent properties of water?

• Sodium chloride is transported as Na+ and Cl– in blood.

• Movement of water occurs under tension in the xylem.

• Water is the coolant in sweat.

• Ice floats on liquid water.

Which properties explain the ability of water to dissolve solutes?

I. Polarity of water molecules

II. High specific heat capacity of water

III. Hydrogen bonding

• I and II only

• I and III only

• II and III only

• I, II and III

Why is sweat a good coolant for the body?

• The arterioles that transfer water to sweat move closer to the skin surface when it is hot.

• Breaking H bonds between water molecules in sweat requires energy from body heat.

• Sweat contains minerals such as sodium chloride.

• Sweat is non-polar.

What is a consequence of the specific heat capacity for liquid water, ice and water vapour?

• Less energy is needed to warm water vapour than liquid water.

• Salt dissolves more readily in liquid water than in ice.

• Small insects can walk on liquid water.

• Ice floats on liquid water.