Ocean Water Chemistry

Earth’s Water Chapter 4.3Pages 127-131

Before Reading…

• Besides Salt, what are some important characteristics of Ocean water?– Think about how oceans differ from lakes

and rivers.

Pages 127 & 128½• Where does ocean salt come from?• What is Salinity?–What is the average salinity of ocean water?– List some places where Salinity varies. Why?– Describe 2 effects Salinity has on water.

Pages 127 & 128½• Where does ocean salt come from?• Chemicals from volcanoes and rocks

washed into the ocean• What is Salinity?• Total amount of dissolved salts in water–What is the average salinity of ocean

water?– 35g of salt per 1,000g (35ppt)

Pages 127 & 128½– List some places where Salinity varies.

Why?– Salinity is lower at the ocean surface and

mouths of rivers because of rain and a constant supply of fresh water. Salinity is high at the poles because water freezes, leaving the salt behind.

– Describe 2 effects Salinity has on water.– Salt makes the freezing point of water

lower and increases density, allowing more dense objects to float.

Page 129• Write the formula for Density.• Which to gases are important for

organisms living in ocean water?–Why is oxygen more abundant near the

ocean’s surface?

• How does temperature affect ocean water?

Page 129• Write the formula for Density.

D = m / V• Which two gases are important for organisms

living in ocean water?• Oxygen and Carbon dioxide– Why is oxygen more abundant near the ocean’s

surface?– Algae near the surface create oxygen from

photosynthesis

• How does temperature affect ocean water?• Colder water can hold more oxygen.

Page 130• What 2 properties change with Depth?• Temperature and Pressure– Define each of these properties– Temperature: amount of energy of nearby

molecules– Pressure: amount of force over a given area– How do they change as depth increases?– Temperature decreases while pressure increases

• Give another property that changes with depth.

• Density increases as depth increases.