Core component 1 - Water Flashcards Preview

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Flashcards in Core component 1 - Water Deck (13)
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1
Q

Describe the structure of a water molecule and how they can join together

A

The water molecule is a dipole (polar molecule) - has a positively charged end and a negatively charged end. Hydrogen bonds can form between the positive charge on a hydrogen and the negative charge on the oxygen atom of another water molecule.

2
Q

How can water act as a solvent?

A

Because water molecules are dipoles, they attract charged particulars such as ions and other polar molecules, such as glucose. However, non- polar molecules such as lipids do not dissolve in water.

3
Q

Why is it useful that water can act as a solvent?

A

1) Living organisms can obtain their key elements from aqueous solution.
2) Water can act as a transport medium
3) Substanes can dissolve in water, so chemical reactions can take place in solution.

4
Q

How does water act as a metabolite?

A

1) Reactant in photosynthesis and hydrolysis

2) Product of aerobic respiration and condensation reactions

5
Q

What is a high specific heat capacity?

A

This means a large amount of heat energy is needed to raise its temperature.

6
Q

Why is it useful that water have a high specific heat capacity?

A

1) This prevents large fluctuations in water temperature
2) Important to keep aquatic habitats stable - so organisms do not have to adapt to extremes of temperature and enzymes within cells can work efficiently

7
Q

What does high latent heat of vaporisation mean?

A

This means a lot of heat energy is needed to change it from a liquid to a vapour

8
Q

Why is high latent heat of vaporisation an important feature of water?

A

1) It’s important in temperature control - heat is used to vaporise water from sweat on the skin or from a leaf’s surface. As the water evaporates, the body cools.
2) So much energy would be required to vaporise all the water that aquatic habitats rarely evaporate away.

9
Q

What is cohesion ?

A

When the water molecules attract each other forming hydrogen bonds. There are so many molecules and they stick together in a lattice - this is called cohesion.

10
Q

Why is cohesion an important feature of water?

A

It allows columns of water to be drawn up xylem vessels in plants.

11
Q

How does water have a high surface tension at normal temperatures?

A

In a pond, for example, cohesion between water molecules molecules at the surface produces surface tension.

12
Q

Why is high surface tension an important feature of water?

A

Insects, such as the pond skater, can live on the top of the water providing support

13
Q

What else does water provide which is useful?

A

Buoyancy

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