Chapter 12: Properties of Water Flashcards
What is the shape and type of bonding that a water molecule has?
V-shaped, contains polar covalent bonds
Why are water molecules polar?
An overall dipole exists as a result of the unsymmetrical nature of the polar O-H bonds, and the difference in electronegativity of oxygen and hydrogen
What are the strength of the forces that attract water molecules to each other?
As a result of the bonds between hydrogen and oxygen, the forces that attract water molecules to each other are strong hydrogen bonds
How many bonds can water molecules form with other water molecules?
Each water molecule can form up to four hydrogen bonds with other water molecules
What does the strength of the hydrogen bonds of water mean in terms of energy required to disrupt these bonds?
Relatively large amounts of energy are required to disrupt the bonds and seperate the molecules from each other, giving water relatively high melting and boiling points
What is the trend in boiling and melting point of group 16 hydrides?
They increase down the group, due to the increasing strength of dispersion forces
What is the exception in the trend of group 16 hydrides?
Water has significantly higher melting and boiling points due to its strong hydrogen bonds
Why is ice less dense than liquid water?
Its unique geometric arrangement of water molecules in a rigid, hexagonal structure with definite gaps, as a result of hydrogen bonding
What is heat capacity defined as?
A measure of a substance’s capacity to absorb and store heat energy
What does the specific heat capacity of a substance measure?
The quantity of energy in joules needed to increase the temperature of 1 gram of substance by one degree Celsius
Why is the specific heat capacity of water relatively high?
Due to the ability of the hydrogen bonds between water molecules to absorb and store heat energy
What is the correlation between grams and millilitres?
The mass of a sample of liquid water in grams is equal to its volume in millilitres
How can the heat energy required to increase a given mass of substance by a particular temperature be calculated?
Heat Energy (joules) = Specific Heat Capacity x Mass of Substance x Temperature Change
What is latent heat?
The energy absorbed by a fixed amount of substance as it changes state from a solid to a liquid or a liquid to a gas, which does not result in a change in temperature
What is the latent heat of vaporisation of a substance?
The heat energy required to change 1 mole of the substance from a liquid to a gas at its boiling point
