Water

• What is the chemical formula of water?

  H2O
• What atoms make up one water molecule?

  • 2 hydrogens
  • 1 oxygen
• What type of molecule is water regarding its special charge?

  Water is a polar molecule.
• What charge do oxygen atoms in water carry?

  Oxygen atoms in water are slightly negatively charged.
• What charge do hydrogen atoms in water carry?

  Hydrogen atoms in water are slightly positively charged.
• How do water molecules bond to one another?

  Water molecules bond through hydrogen bonds.
• Are hydrogen bonds strong?

  No, hydrogen bonds are weak.
• How does hydrogen bonding work in water molecules?

  Hydrogen bonding occurs when the partially negative oxygen is attracted to a partially positive hydrogen in another water molecule.
• What are two examples of metabolic reactions that involve water?

  • Hydrolysis
  • Condensation
• In hydrolysis, what happens to a bond and a water molecule?

  In hydrolysis, a bond is broken and a water molecule is used.
• In condensation reactions, what happens to a bond and a water molecule?

  In condensation reactions, a bond is formed and a water molecule is produced.
• What is the specific latent heat of vaporization?

  It is the heat energy required to change a unit mass of substance from liquid to gas.
• Why does water have a high specific latent heat of vaporization?

  Water has a high specific latent heat of vaporization due to lots of hydrogen bonding.
• Why is water's high specific latent heat of vaporization useful?

  It is useful in sweating because when water evaporates, energy is used up and cools the environment.
• What is specific heat capacity?

  Specific heat capacity is the amount of energy required to increase the temperature of 1 kg of a substance by 1°C.
• How does water's heat capacity compare?

  Water has a high heat capacity.
• Why is the high heat capacity of water useful?

  It is useful to disperse heat around the bodies of warm-blooded animals and makes water's stable temperature suitable for aquatic life/ecosystems.
• What type of solvent is water?

  Water is a good solvent.
• Why is water a good solvent?

  Water is a good solvent because it is a polar molecule and the charged ends of the water molecule attract ions of the opposite charge, allowing ions to dissolve easily in it.
• What is cohesion of water also known as?

  Cohesion of water is also known as surface tension.
• Why is water cohesive?

  Water is cohesive due to hydrogen bonding.
• When does surface tension occur?

  Surface tension occurs when water meets air.
• Why is water's cohesion useful?

  Water's cohesion is useful because it allows water to be pulled up the xylem vessel in plants and helps pond skaters walk on water.
• Why is water essential for plants?

  Water is essential for plants because it is necessary for photosynthesis.
• Why is water good in plant cells?

  Water provides structure in plant cells as it cannot be easily compressed.
• What is the structure of a water molecule?

  One oxygen atom and two hydrogen atoms
• Why is water considered a polar molecule?

  Due to unequal distribution of electrons
• What are the key properties of water?

  High specific heat, cohesion, solvent, metabolite
• How does water’s high specific heat capacity benefit organisms?

  It minimizes temperature fluctuations
• How does water's high latent heat of vaporization help organisms?

  It allows cooling through evaporation
• What is cohesion in water?

  Attraction between water molecules
• Why is cohesion important for plants?

  It enables water to be pulled up the xylem
• Why is water an excellent solvent?

  Its polarity allows it to dissolve ionic compounds
• Why is water described as a metabolite?

  It is involved in metabolic reactions
• What are hydrogen bonds?

  Weak interactions between water molecules
• How do hydrogen bonds affect water’s properties?

  They provide high cohesion and surface tension
• Why is surface tension important in water?

  It allows small organisms to move on water
• What is the role of iron ions (Fe²⁺) in biology?

  Component of haemoglobin for oxygen transport
• What is the role of phosphate ions (PO₄³⁻) in biology?

  Part of DNA, RNA, and ATP
• How do hydrogen ions (H⁺) affect biological systems?

  They determine the pH of solutions