Chapter 1.1 Chemistry For Life

Question 1

Define anion

Answer 1

Negative ion formed when an atom gains electrons

Question 2

Define cation

Answer 2

Positive ion, formed when an atom loses electrons

Question 3

What is ionic bonds ?

Answer 3

Attractive forces between oppositely charged ions

Question 4

How is a covalent bond formed ?

Answer 4

When atoms share electrons to have full outer shell

Question 5

What is a dipole ?

Answer 5

Separation of charge in a molecule when the electrons in covalent bonds are not evenly shared

Question 6

What is a polar molecule ?

Answer 6

A molecule containing a dipole

Question 7

What is a hydrogen bond?

Answer 7

Weak electrostatic intermolecular bonds formed between polar molecules that contains at least 1 hydrogen atom

Question 8

What is atom made up of?

Answer 8

Nucleus which contains protons and neutrons as well as electrons

Question 9

Why does an atom with full outer shell not take part in chemical reactions?

Answer 9

Because it is stable so there’s no need to get electrons or to give electrons

Question 10

What happens in order for atoms to have ionic bonding?

Answer 10

Atoms must gain or lose electrons

Question 11

Is ionic bonds easy to break?

Answer 11

No. Ionic bonding has a strong intermolecular forces between the atoms

Question 12

What happens in covalent bonding ?

Answer 12

Atoms share electrons to have a full outer shell

Question 13

True or false. Covalent bond is weak

Answer 13

False. Covalent bonds are very strong.

Question 14

What does it mean when molecules in covalent bonds are polarised?

Answer 14

The electrons in the covalent bonds are not evenly shared so the molecule has a part that is slightly negative and slightly positive part.

Question 15

In order for molecules to have polarity what atom is needed?

Answer 15

Hydrogen atoms

Question 16

What happens when ionic substances dissolve in water ?

Answer 16

The ions separate

Question 17

Does most ionic substances exist as a positive or negative ions in the cell?

Answer 17

Yes. This is because cells are 60-70% water. So ionic substances can dissolve

Question 18

Give formula for nitrate ions

Answer 18

-

NO3

Question 19

Give formulae for phosphate ions

Answer 19

-3

PO4

Question 20

Give formula for chloride ions

Answer 20

-

Cl

Question 21

Give formula for hydrogen carbonate

Answer 21

-

HCO3

Question 22

What is nitrate ions needed for?

Answer 22

Needed for plants for the formation of amino acids

Question 23

What is phosphate ions needed for ?

Answer 23

Needed for all living organisms in the formation of ATP and ADP as well as DNA and RNA

Question 24

What is chloride ions needed for ?

Answer 24

Needed in nerve impulses and many secretory systems

Question 25

What is hydrogen carbonate ions needed for?

Answer 25

Needed for buffering the blood to prevent it from becoming too acidic

Question 26

Give formula for sodium ion

Answer 26

+ | Na

Question 27

Give formula for calcium ions

Answer 27

2+ | Ca

Question 28

Give formula for hydrogen ions

Answer 28

+ | H

Question 29

Give formula for magnesium ions

Answer 29

2+ | Mg

Question 30

What is sodium ions needed for ?

Answer 30

Needed in nerve impulses and many secretory systems

Question 31

What is calcium ions needed for ?

Answer 31

Needed for the formation of calcium peerage for the middle lamella between two cell walls in plants and for bone formation and muscle contraction in animals

Question 32

What is hydrogen ions needed for?

Answer 32

Needed in cellular respiration and photosynthesis and in numerous pumps and systems in organisms as well as pH balance

Question 33

What is magnesium ions needed for?

Answer 33

Needed for production of chlorophyll in plants

Question 34

What allows substance to be able to move around the body

Answer 34

Water

Question 35

What is the chemical formula for water?

Answer 35

H2O

Question 36

Is water a polar molecule?

Answer 36

Yes. Electrons held closer to the oxygen atom than hydrogen atom so oxygen atom have a slightly negative charge

Question 37

What bond does water molecules form?

Answer 37

Hydrogen bonds

Question 38

What happens in hydrogen bond ?

Answer 38

The slightly negative oxygen atom will attract the slightly positive hydrogen atom

Question 39

Why does water have high melting and boiling point compared with other substances that have molecules of similar size?

Answer 39

As there are many hydrogen bonds it takes lots of energy to break the bond

Question 40

What 2 things does hydrogen bond play important role in ?

Answer 40

1. Protein structure | 2. Structure and functioning of DNA

Question 41

Is water a water solvent ?

Answer 41

Yes. Water is a polar molecule so any ionic substances will dissolve.

Question 42

True or false. Many covalent substances are polar

Answer 42

True and sometimes dissolve in water

Question 43

Can covalent substances dissolve in other covalently bonded solvents (ethanol)

Answer 43

No

Question 44

What makes water a excellent transport medium?

Answer 44

The fact that many different substances can dissolve in it

Question 45

At what temperature does water reaches its maximum density?

Answer 45

4°C

Question 46

What happens to water as it becomes cooler than 4 Celsius

Answer 46

The molecule become more widely spaced

Question 47

True or false. Ice is more dense than water

Answer 47

False. Ice is less dense than water

Question 48

Is water a insulating player?

Answer 48

Yes it prevents underneath water from freezing

Question 49

Why can animals live underwater?

Answer 49

Water is a insulating layer so it stops underneath water to freeze

Question 50

Does water have a high specific heat capacity?

Answer 50

Yes. Water is slow to absorb and release heat. And it helps to maintain the temperature throughout the year

Question 51

Does hydrogen bond require a lot of energy to be broken

Answer 51

Yes

Question 52

Can water be compressed

Answer 52

No.

Question 53

What does it mean when water molecules are cohesive ?

Answer 53

The water molecules can stick together

Question 54

Why is the fact that water molecules are cohesive important?

Answer 54

It’s important for the movement of water from roots to the leaves of the plant

Question 55

What does it mean when water molecules are adhesive?

Answer 55

They are attracted to different molecules

Question 56

Why is it important for water molecule to be adhesive?

Answer 56

Important in plant transport and in surface tension

Question 57

Why does water have a high surface tension?

Answer 57

Because of the hydrogen bonds. The attraction between the water molecules are greater than air