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Biology OCR (3, biological molecules) > Water > Flashcards

Flashcards in Water Deck (38)
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1

Draw the structure of an oxygen atom

2

Draw the structure of a hydrogen atom

11`

3

Draw a dot and cross diagram for a water molecule

1

4

Is a water molecule polar or non-polar?

Polar

5

What does it mean if an atom is delta negative?

The electrons in the molecule spend more time closer to that atom

6

What does it mean if an atom is delta positive?

The electrons in the molecule spend more time far away from that atom

7

In a water molecule which of the atoms are delta positive and which are delta negative?

Oxygen = delta negative Hydrogen = delta positive

8

What is a polar molecule?

There are regions of negativity and regions of positivity in the molecule (the electrons are not evenly distributed).

9

A molecule which consists of just an oxygen and a hydrogen (OH) is known as what?

A hydroxyl

10

What functional group does water molecules consist of?

A water molecule contains two hydroxyl groups

11

Why do water molecules stick together?

The partial charges of the hydrogen and oxygen atoms attract each other to create hydrogen bonds. These bonds allow each water molecule to interact with each other (essentially sticking them together)

12

Draw a diagram of two water molecules, along with the partial charges and the hydrogen bonds

2

13

What are hydrogen bonds?

Hydrogen bonds are electrostatic attraction between two partial charges of a polar molecule. They are relatively weak and so are easy to break and reform along with the constantly moving water molecules.

14

What are hydrogen bonds?

Hydrogen bonds are electrostatic attraction between two partial charges of a polar molecule. They are relatively weak and so are easy to break and reform along with the constantly moving water molecules.

15

Because hydrogen bonds are weak, how do they actually keep the water molecules together?

There is a very large number of hydrogen bonds between the water molecules. These large numbers are what keep the molecules together and create the properties of water.

16

How is an oxygen atom and a hydrogen atom bonded

Via a covalent bond

17

What are the 7 properties of water that make it useful?

  • Solvent
  • Surface tension
  • Density
  • Latent heat capcity
  • Specific heat capacity
  • Cohesion
  • Adhesion

18

What is specific heat capacity?

The amount of energy needed to raise 1 gram of a substance by 1 degree

19

Why does water having a high specific heat capacity make it useful?

It means that the temperature of water can remain relatively constant. Water is able to absorb a lot of heat in the summer without reaching as high of a temperature itself. Water is then able to release this heat energy in the winter as it cools.

20

Explain how the property of water having a high specific heat capacity keeps the fishes alive?

The water is able to remain at a constat temperature. This protects the enzymes that are involved in the metabolism of fish from being damage by extreme temperatures.

21

What is cohesion of water?

Water molecules stick to each other.

22

What is adhesion of water?

Water molecules stick to other substances

23

Explain how the property of cohesion can be useful in plants?

Plants are able to draw water up through their roots because the water molecules stick together and pull each other along

24

How is the property of adhesion useful for plants?

It allows the plant to pull water up through the roots because the water molecules stick to the walls of the xylem in plants.

25

Why is water a good solvent?

Water is a polar molceule and so is a great solvent for other polar molecules. 

26

Because water is a solvent what substances is it able to transport?

  • Nutrients
  • Excretory products
  • Hormones
  • Digestive juices

27

How does the property of water being a greate solvent make it useful?

It means that water is great at transporting stuff and braking down big molecules in hydrolysis.

28

What does cohesion result in?

Water having a high surface tension

29

How is the property of cohesion useful?

It means that water is able to resist external forces.

30

How is the property of cohesion useful for pond skaters?

It means that they can walk on water