Chemistry Of Watwr Flashcards
What are the physical properties of water
- high heat capacity
- high melting and boiling points in comparison to other similar molecules
- a slow rate of evaporation and low volatility
- lower density in the solid state than in the liquid state
- effective as a solvent
- high surface tension
- strong capillary function
At What temperature does water reach its highest density
4 degrees
Explain why water in the solid state has a lower density then water in the liquid state
As water in the liquid state cools to temperatures below 0 degrees. The water changes to the solid phase and forms ice crystals. Hydrogen bonds are very strong and are held in a crystal lattice. Each water molecule in the ice crystal is bonded to four hydrogen bonds in a tetrahedral structure in three dimensional hexagonal rings. Repetition of these rings yields and open structure which causes the density of ice to be lower then water
How does the nature of water protect nature
Ice has a lower density than water and thus floats on water and to some extent prevents the water from freezing as it traps heat. Was it not for this fact the ice would’ve sunken to the bottom and everything would freeze
Why does water have higher melting and boiling points
Hydrogen bonds
How does the high melting and boiling points of water support life
If water did not have hydrogen bonds it would’ve melted at -100 degrees and boiled at -91 degrees. Thus all water on earth would be water vapour and life ok earth would be impossible as humans and animals need water to drink to survive and aquatic animals water is their habitat
What cause ice to melt in water and become cold
Ice absorbs heat from water and melts and because heat absorbed by one substance is released by another hence water releases the heat which results in cooking
What is temperature
The measure of the average speed and average kinetic energy of the particles of a substance
What is the heat capacity of a substance
The energy that is transferred to the substance to increase the temperature
What is specific heat capacity
The amount of heat that is needed to increase the temperature of 1 kilogram of a substance by 1 degree
What happens when water evaporates
When water evaporates, the surface molecule with the highest kinetic energy overcomes intermolecular forces. The remaining molecules having lower average kinetic energy remain behind. Hence since the average kinetic energy of the substance is less the temperature also decreases and cooling takes place
How does water evaporating sustain life
When it’s too hot out body released water which evaporates and leads to cooling on our body and preventing overheating
How does water as a solvent sustain life
The nutrients we eat are dissolved in water and transported by our bodies to be absorbed by cells. Plants are dependent on the nutrients dissolved in water from the soil
What is surface tension
The resistance that a liquid offers against a force that is threatens to enlarge its surface
What causes surface tension in water
Water molecules inside water liquid undergoes reasonably symmetrical attractive forces due to other similar molecules surrounding it on all sides. Water molecule on the surface however only experience sideways and downwards forces. These pull away as many water molecules as far away as possible from the surface of the water. Thus there are the least number of water molecules on the surface causing it to be more densely than the rest of the water. This causes the surface of water to have surface tension
