Chapter 10 Flashcards
(41 cards)
What is the most abundant liquid on earth?
Water.
What liquid covers 70% of the planet?
Water.
What states does water exist in one Earth?
Solid, liquid, gas.
Where is the water cycle said to begin?
With evaporation.
What is the main human activity that contributes to the water cycle?
The combustion of fossil fuels, which produces steam.
What is the photosynthesis overall process equation?
6H2O(l) + 6CO2(g) –(chlosophyll, sunlight)–> C6H12O6(s) + 6O2(g)
What is the photosynthesis word equation?
Water + Carbon dioxide –(chlorophyll, sunlight)–> Glucose + Oxygen
What is the respiration word equation?
Glucose + Oxygen –> Water + Carbon dioxide
What is the respiration overall equation?
C6H12O6(s) + 6O2(g) –> 6H2O(l) + 6CO2(g)
Name three functions of water?
- Provides a system to transport nutrients and soluble waster - can act as a solvent and dissolve materials which helps in transporting materials to living things.
- Provides a system to transfer heat - has the capacity to store a large amount of heat energy.
- Provides a system to cool the body - when water is evaporated from the skin it absorbs heat from the body.
What does the evaporation stage produce?
Water free of dissolved substaces.
Describe two points about waters bonds?
- The oxygen-hydrogen bonds are polar with the oxygen atoms having a larger share of electrons because of its higher electronegativity
- Foces between water are hydrogen bonds which are stronger in comparison to other intermolecular bonds
Why does water have higher melting point?
- As an ice crystal water molecules are structured with each molecule forming hydrogen bonds with four other molecules
- For ice to melt energy must be provided to increase the kinetic energy of the water molecules where they can break free of the crystal lattice
- High melting temperature indicates the high amount of energy needed
Why does water have a higher boiling point?
- When water is boiled the molecules are separated from each other
- Energy is needed to overcome these hydrogen bonds between the molecules
What is latent heat fusion of water?
The amount of energy needed to change a fixed amount of water from a solid to a liquid at 0 degrees celsius.
What is latent heat of vaporisation of water?
The amount of energy needed to change a fixed amount of water from a liquid to a gas at 100 degrees celsius.
Whats denser liquid or water and by how much?
Water is 10% denser than ice.
What does the specific heat capacity of a substance measure?
The amount of heat energy needed to increase the temperature of that substance by 1 degree celsius.
What is the specific heat capacity of water?
4.2 joules.
What does a higher specific heat capacity mean?
The more effectively it will store heat energy.
What is the formula for heat capacity?
HE = SHC x mass(g) x change in temp (degrees celsius)
Why does water expand when its frozen?
- Molecules slow down when they are cooled and form an ice lattice
- Each water molecule forms a bond with 4 surrounding water molecules
- This is an open arrangement with the molecules being more widely spaced in ice than water
Why is water denser than ice?
- Molecules in ice are widely spread
- Molecules in water move more closely together and the density decreases
What are three characteristics of solutions?
- They are homogeneous, the solute and solvent cant be distinguished from eachother
- Dissolved particles are too small to see
- Proportion of dissolved solute varies from one solution to another
