4. Temperature and Density of Seawater Flashcards
Explain why salinity increases the density of seawater.
Because when salinity increases, it means there is more salt content within the seawater, increasing the density of seawater.
Multiple Choice:
Addition of river water or rainwater ……………salinity, excess evaporation causes salinity to ………………
A.) Increase, increase
B.) Decrease, increase
C.) Decrease, decrease
D.) Increase, decrease
Addition of river water or rainwater ……………salinity, excess evaporation causes salinity to ………………
B.) Decrease, increase
Salt water is more dense at its freezing point.
True/False
True
Salt water is more dense at its freezing point.
What is the formula for finding density?
Where:
d= density
m= mass in grams
V= volume in millilitres
1mL (volume of liquid) is equivalent to how many cm3?
1mL (volume of liquid) = 1cm3 (volume of solid)
Explain why ice floats on seawater? Discuss it in terms of density.
(Really long)
Ice floats on seawater because it is less dense than seawater. Ice has a crystal lattice structure, where hydrogen bonds make the molecules more spread out and therefore less dense. Seawater is more dense as it is in liquid form where the molecules are more closer together, plus there is also lots of salt content, making it more dense. Therefore, the less dense rises and more dense sinks. Hence, ice (less dense) floats on seawater (more dense).
What is the effect on the volume of the ocean if all the ice at the North Pole melted? (Long)
If all the ice at the North Pole melted, the volume of the ocean would decrease. This is becuase when water is in ice form, it is less dense as the hydrogen bonds create a lattice structure and the molecules are more spread out. When it melts into liquid form, the hydrogen bonds break from the lattice structure, making the molecules more dense and therefore decreasing in volume.
Explain why fresh water is most dense at 4 degrees? Explain why it becomes less dense.(Long)
As water cools (in liquid form), it becomes more dense as the molecules contract due to the cold. However lower than 4degrees it becomes less dense as it starts to freeze. As it starts to freeze, hydrogen bonding creates a lattice structure and hence it becomes less dense.
When water is heated (to gas form), the molecules are spread more apart, meaning it becomes less dense.
True/False
In freshwater, when temperature increases, density also increases.
False, when temperature increases, density decreases. (Molecules more spread apart)
What is the relationship bewteen density and salinity?
As density increases, salinity also increases.
What are the units given for density?
g/ mL
What happens to the density of seawater as temperature increases?
As temperature increases, density decreases.
