Water

• AThe oxygen atoms form ionic bonds with bicarbonate ions
• BThe oxygen atoms in water attract bicarbonate ions
• CThe hydrogen atoms form hydrogen bonds with bicarbonate ions
• DThe hydrogen atoms in water attract bicarbonate ions

• AHeat loss through evaporation of sweat
• BEnzyme function
• CAquatic ecosystems withstanding extreme temperature change
• DHumans living in sub-zero temperatures

• AWater-loving; polar or charged molecules that can form hydrogen bonds with water
• BWater-hating; non-polar molecules that cannot form hydrogen bonds with water
• CThe attraction between water molecules and other water molecules
• DThe attraction between water molecules and other polar or charged surfaces

• AHydrogen bonds are strong, permanent bonds that do not break
• BHydrogen bonds form between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another
• CHydrogen bonds form between the slightly negative hydrogen of one water molecule and the slightly positive oxygen of another
• DHydrogen bonds are covalent bonds within a water molecule

• AHigh surface tension
• BHigh specific heat capacity
• CCohesion between water molecules
• DAbility to dissolve non-polar molecules
• ELow viscosity

• AWater is a universal solvent due to its polarity
• BNon-polar molecules dissolve easily in water
• CSodium chloride and urea are highly soluble in water
• DHydrophobic molecules join together due to hydrophobic interactions
• EOxygen is completely insoluble in water

True or false?

True or false?

True or false?

• Water and solutes became trapped within a membrane
• Chemical reactions began occurring within the membrane-bound structure
• The first cells evolved in a watery environment
• This led to the evolution of cells

• AHydrogen bonds form between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of an adjacent water molecule.
• BHydrogen bonds are strong, permanent bonds that hold water molecules together permanently.
• CWhen few hydrogen bonds are present they are constantly breaking and reforming.
• DHydrogen bonds form because water is a non-polar molecule.
• EHydrogen bonds are responsible for water's high specific heat capacity.

• ABase-pairing between two strands of DNA
• BThe bond joining one nucleotide to its neighbour in a strand of DNA
• CThe hydrogen bonds between strands of cellulose that give it tensile strength
• DInteractions between mRNA and tRNA during protein synthesis
• EThe covalent bond between oxygen and hydrogen within a single water molecule

• AHigh surface tension
• BHigh specific heat capacity
• CCohesion between water molecules
• DAbility to dissolve non-polar substances such as fats
• EAbility to act as a solvent for polar and charged molecules

• AWater has a specific heat capacity of 4200 J/kg/°C.
• BThe high specific heat capacity of water is due to the many hydrogen bonds present.
• CWater's thermal conductivity is almost 30 times higher than that of air.
• DThe specific heat capacity of water is lower than that of air.
• EA lot of thermal energy is required to break the hydrogen bonds in water, so its temperature does not fluctuate greatly.

• Water evaporates from the leaves, pulling the column of water upwards.
• Hydrogen bonds between water molecules create cohesion.
• Water is drawn into the roots and moves into the xylem.
• Water molecules adhere to the cellulose in the xylem walls.

• Oxygen
• Sodium chloride
• Cholesterol
• Hydrophobic amino acid

True or false?

• AThe energy required to raise the temperature of 1 kg of a substance by 1°C.
• BThe energy required to change one mole of liquid into one mole of gas.
• CThe energy required to change one mole of solid into one mole of liquid.
• DThe ability of a substance to conduct heat.

• ABase-pairing between two strands of DNA
• BThe forces that hold water molecules together
• CThe bond that joins one nucleotide to its neighbour in a strand of DNA
• DInteractions between water and the polar R groups of certain amino acids

• AI only
• BI and II
• CII, III and IV
• DIII only

• AThe covered cup cools more slowly because water has a high specific heat capacity, similar to how sweating cools the body.
• BThe uncovered cup cools more slowly because water has a high latent heat of vaporisation, similar to how sweating cools the body.
• CThe covered cup cools more quickly because water has a low specific heat capacity, similar to how sweating cools the body.
• DThe uncovered cup cools more quickly because water has a high latent heat of vaporisation, similar to how sweating cools the body.

• AHalf as much energy; the liquid has fewer hydrogen bonds than water
• BTwice as much energy; the liquid has more hydrogen bonds than water
• CThe same energy; the liquid has the same number of hydrogen bonds as water
• DOne quarter as much energy; the liquid has no hydrogen bonds at all

• ADensity decreases because water molecules move slower and pack less closely
• BDensity increases because the molecules lose kinetic energy and move closer together
• CDensity stays the same because water is incompressible
• DDensity decreases because hydrogen bonds break and the structure collapses

• AWater molecules are cohesive and adhere to the polar glass but not to the non-polar oil
• BWater molecules are adhesive and cohere to the non-polar oil but not to the polar glass
• CThe oil has a higher specific heat capacity than glass, so the water evaporates more slowly
• DThe glass is hydrophobic and the oil is hydrophilic, so water behaves differently on each

• AIt is likely to be polar.
• BIt probably forms hydrogen bonds between its molecules.
• CIt is likely to be non-polar.
• DIt probably has weak intermolecular forces.
• EIt could support stable aquatic habitats.

• AEvaporation of water from the cloth removes heat from Cup A.
• BWater has a high latent heat of vaporisation, so it absorbs a lot of energy when evaporating.
• CThe wet cloth increases the specific heat capacity of the water inside Cup A.
• DThe wet cloth acts as an insulator, reducing heat loss by conduction.
• ECup B loses heat faster because it has a lower specific heat capacity.

• ADetergent molecules disrupt hydrogen bonds between water molecules at the surface.
• BSurface tension is reduced by the detergent.
• CDetergent increases the density of water, so the pond skater can no longer float.
• DDetergent molecules are non-polar and break covalent bonds within water molecules.
• EThe pond skater relies on the high surface tension of water to support its weight.

True or false?

True or false?

Specific heat capacity is a measure of the energy required to raise the temperature of 1 kg of a substance by ____ °C.

The property is ____.

In a water molecule, the oxygen atom attracts electrons more strongly than hydrogen, creating a weak negative region (δ−) on the oxygen and a weak positive region (δ+) on the hydrogen atoms. This separation of charge is called a ____.

• A5040 J/kg/°C
• B4620 J/kg/°C
• C3780 J/kg/°C
• D4200 J/kg/°C

• A1200 J/kg/°C
• B1100 J/kg/°C
• C900 J/kg/°C
• D1000 J/kg/°C

• A30 times
• B27 times
• C33 times
• D36 times

• A75600 J
• B84000 J
• C100800 J
• D92400 J

• A1890 J/kg/°C
• B2310 J/kg/°C
• C2100 J/kg/°C
• D2520 J/kg/°C