AICE MARINE SCIENCE REVIEW EXAM
QUESTIONS AND ANSWERS GRADED A+
2025/2026
Unit 1: Water
1.1.1 explain the changes of state in water, between solid, liquid, and gas, in terms of the kinetic
particle theory - ANS The kinetic particle theory explains changes in the state of water as
transitions between solid, liquid, and gas. In a solid state, water molecules are closely packed
and vibrate around fixed positions due to minimal kinetic energy. As heat is applied, the kinetic
energy of the molecules increases, causing them to break free from their fixed positions and
transition into the liquid state, where they have more freedom of movement but still remain
close together. Further heating causes molecules to gain even more kinetic energy, overcoming
intermolecular forces completely, leading to the gas phase where molecules move freely and
independently.
1.1.2 describe the structure of the atom, including the nucleus containing protons and
neutrons, surrounded by electrons arranged in shells - ANS Atoms consist of a nucleus
containing protons and neutrons, surrounded by electrons arranged in energy levels or shells.
1.1.3 understand that seawater is a mixture of different elements and compounds - ANS Sea
water is a mixture composed of various elements and compounds dissolved in water. It contains
ions such as sodium (Na+), chloride (Cl-), magnesium (Mg2+), sulfate (SO4^2-), calcium (Ca2+),
and carbonate (CO3^2-),
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,1.1.4 describe (including through the use of diagrams) the covalent bonding in a water
molecule, limited to the sharing of electron pairs between atoms - ANS Covalent bonding in a
water molecule involves the sharing of electron pairs between atoms. In a water molecule
(H2O), each hydrogen atom shares a pair of electrons with the oxygen atom, resulting in the
formation of two covalent bonds. This sharing of electrons allows each atom to achieve a stable
electron configuration.
1.1.5 Identify covalent molecules - ANS Covalent molecules include water (H2O), carbon
dioxide (CO2), oxygen (O2), sulfur dioxide (SO2), and glucose (C6H12O6). In these molecules,
atoms are bonded together through the sharing of electron pairs.
1.1.6 describe the ionic bonding in sodium chloride, limited to the loss and gain of electrons to
form ions and the subsequent attraction between positive and negative ions - ANS Ionic
bonding in sodium chloride (NaCl) occurs through the transfer of electrons from sodium atoms
to chlorine atoms, resulting in the formation of positively charged sodium ions (Na+) and
negatively charged chloride ions (Cl-). These oppositely charged ions are then attracted to each
other through electrostatic forces, forming an ionic bond.
1.1.7 identify ionic substances, including sodium chloride and calcium carbonate - ANS Ionic
substances, such as sodium chloride (NaCl) and calcium carbonate (CaCO3), consist of ions held
together by ionic bonds
1.1.8 state the chemical name and formula of salts found in sea water,including sodium chloride
(NaCl), magnesium sulfate (MgSO4) andcalcium carbonate (CaCO3) - ANS Salts found in sea
water include sodium chloride (NaCl), magnesium sulfate (MgSO4), and calcium carbonate
(CaCO3).
1.1.9 explain the formation of hydrogen bonds in water - ANS Hydrogen bonds in water occur
due to the attraction between the positively charged hydrogen atoms of one water molecule
and the negatively charged oxygen atoms of neighboring water molecules. These bonds are
weaker than covalent bonds but contribute to the unique properties of water.
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, 1.1.10 explain how hydrogen bonding in water affects the properties ofwater, limited to solvent
action, density, and specific heat capacity - ANS Hydrogen bonding in water affects its
properties in several ways:
- Solvent action: Hydrogen bonds allow water to dissolve many substances, making it an
effective solvent.
- Density: Hydrogen bonding causes water to have a maximum density at 4°C, leading to the
unusual property of ice floating on water.
- Specific heat capacity: Hydrogen bonds give water a high specific heat capacity, meaning it can
absorb or release large amounts of heat with minimal temperature change, which is important
for temperature regulation in living organisms and for moderating climate.
1.2.1 explain the terms solute, solvent, solution and solubility - ANS Solute refers to the
substance being dissolved, solvent is the substance doing the dissolving, and solution is the
resulting mixture. Solubility is the maximum amount of solute that can dissolve in a solvent at a
given temperature and pressure.
1.2.2 describe how soluble salts, such as sodium chloride, dissolve in water by the dissolution of
ions - ANS Soluble salts like sodium chloride dissolve in water by breaking into ions (Na+ and
Cl-) due to the solvent's polarity. Water molecules surround and pull apart the salt crystals,
allowing ions to disperse evenly throughout the solution.
1.2.3 explain the effect of water temperature on the solubility of salts - ANS Water
temperature affects solubility: generally, higher temperatures increase solubility, while lower
temperatures decrease it.
1.2.4 define the term salinity as the concentration of dissolved salts in seawater -
ANS Salinity is the concentration of dissolved salts in seawater, typically measured in parts
per thousand (ppt).
1.2.5 (PA) investigate the effect of salinity on the freezing point of water - ANS Higher salinity
lowers the freezing point of water due to the presence of dissolved salts.
3 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
QUESTIONS AND ANSWERS GRADED A+
2025/2026
Unit 1: Water
1.1.1 explain the changes of state in water, between solid, liquid, and gas, in terms of the kinetic
particle theory - ANS The kinetic particle theory explains changes in the state of water as
transitions between solid, liquid, and gas. In a solid state, water molecules are closely packed
and vibrate around fixed positions due to minimal kinetic energy. As heat is applied, the kinetic
energy of the molecules increases, causing them to break free from their fixed positions and
transition into the liquid state, where they have more freedom of movement but still remain
close together. Further heating causes molecules to gain even more kinetic energy, overcoming
intermolecular forces completely, leading to the gas phase where molecules move freely and
independently.
1.1.2 describe the structure of the atom, including the nucleus containing protons and
neutrons, surrounded by electrons arranged in shells - ANS Atoms consist of a nucleus
containing protons and neutrons, surrounded by electrons arranged in energy levels or shells.
1.1.3 understand that seawater is a mixture of different elements and compounds - ANS Sea
water is a mixture composed of various elements and compounds dissolved in water. It contains
ions such as sodium (Na+), chloride (Cl-), magnesium (Mg2+), sulfate (SO4^2-), calcium (Ca2+),
and carbonate (CO3^2-),
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,1.1.4 describe (including through the use of diagrams) the covalent bonding in a water
molecule, limited to the sharing of electron pairs between atoms - ANS Covalent bonding in a
water molecule involves the sharing of electron pairs between atoms. In a water molecule
(H2O), each hydrogen atom shares a pair of electrons with the oxygen atom, resulting in the
formation of two covalent bonds. This sharing of electrons allows each atom to achieve a stable
electron configuration.
1.1.5 Identify covalent molecules - ANS Covalent molecules include water (H2O), carbon
dioxide (CO2), oxygen (O2), sulfur dioxide (SO2), and glucose (C6H12O6). In these molecules,
atoms are bonded together through the sharing of electron pairs.
1.1.6 describe the ionic bonding in sodium chloride, limited to the loss and gain of electrons to
form ions and the subsequent attraction between positive and negative ions - ANS Ionic
bonding in sodium chloride (NaCl) occurs through the transfer of electrons from sodium atoms
to chlorine atoms, resulting in the formation of positively charged sodium ions (Na+) and
negatively charged chloride ions (Cl-). These oppositely charged ions are then attracted to each
other through electrostatic forces, forming an ionic bond.
1.1.7 identify ionic substances, including sodium chloride and calcium carbonate - ANS Ionic
substances, such as sodium chloride (NaCl) and calcium carbonate (CaCO3), consist of ions held
together by ionic bonds
1.1.8 state the chemical name and formula of salts found in sea water,including sodium chloride
(NaCl), magnesium sulfate (MgSO4) andcalcium carbonate (CaCO3) - ANS Salts found in sea
water include sodium chloride (NaCl), magnesium sulfate (MgSO4), and calcium carbonate
(CaCO3).
1.1.9 explain the formation of hydrogen bonds in water - ANS Hydrogen bonds in water occur
due to the attraction between the positively charged hydrogen atoms of one water molecule
and the negatively charged oxygen atoms of neighboring water molecules. These bonds are
weaker than covalent bonds but contribute to the unique properties of water.
2 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
, 1.1.10 explain how hydrogen bonding in water affects the properties ofwater, limited to solvent
action, density, and specific heat capacity - ANS Hydrogen bonding in water affects its
properties in several ways:
- Solvent action: Hydrogen bonds allow water to dissolve many substances, making it an
effective solvent.
- Density: Hydrogen bonding causes water to have a maximum density at 4°C, leading to the
unusual property of ice floating on water.
- Specific heat capacity: Hydrogen bonds give water a high specific heat capacity, meaning it can
absorb or release large amounts of heat with minimal temperature change, which is important
for temperature regulation in living organisms and for moderating climate.
1.2.1 explain the terms solute, solvent, solution and solubility - ANS Solute refers to the
substance being dissolved, solvent is the substance doing the dissolving, and solution is the
resulting mixture. Solubility is the maximum amount of solute that can dissolve in a solvent at a
given temperature and pressure.
1.2.2 describe how soluble salts, such as sodium chloride, dissolve in water by the dissolution of
ions - ANS Soluble salts like sodium chloride dissolve in water by breaking into ions (Na+ and
Cl-) due to the solvent's polarity. Water molecules surround and pull apart the salt crystals,
allowing ions to disperse evenly throughout the solution.
1.2.3 explain the effect of water temperature on the solubility of salts - ANS Water
temperature affects solubility: generally, higher temperatures increase solubility, while lower
temperatures decrease it.
1.2.4 define the term salinity as the concentration of dissolved salts in seawater -
ANS Salinity is the concentration of dissolved salts in seawater, typically measured in parts
per thousand (ppt).
1.2.5 (PA) investigate the effect of salinity on the freezing point of water - ANS Higher salinity
lowers the freezing point of water due to the presence of dissolved salts.
3 @COPYRIGHT 2026 ALLRIGHTS RESERVED.
