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Flashcards in 2.2* Deck (318)
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1

What is a hydrogen bond?

A weak interaction that can occur whenever molecules contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen atom.

2

What is a hydrolysis reaction?

A reaction that occurs when a molecule is split into two smaller molecules with the addition of water.

3

What is a monomer?

A small molecule which binds to many other identical molecules to form a polymer.

4

What is a polymer?

A large molecule made from many smaller molecules called monomers.

5

What do atoms consist of?

A nucleus ( protons and neutrons ) surrounded by shells of electrons.

6

When are its atoms stable?

When their outermost shell is full.

7

Describe covalent bonding.

Atoms of different elements have different amount of atoms in their outermost shells. For example, carbon has four electrons. By sharing electrons with other atoms, the atom's outermost shell can be 'filled' and it becomes strongly bonded with the other atom.

8

What is a condensation reaction?

Reaction that occurs when two molecules are joined together with the removal of water.

9

How is a covalent bond drawn?

By a single line (the equivalent of sharing one electron)

10

Explain the covalent bonding of methane.

Because carbons outer shell is filled by four electrons, carbon forms four covalent bonds.

11

How many covalent bonds do oxygen, hydrogen and nitrogen form?

Hydrogen forms a single covalent bonds, oxygen two covalent bonds and nitrogen three covalent bonds.

12

Describe the carbon-hydrogen bond.

The carbon-hydrogen bond is one of the most important in organic molecules . Hydrogen has one electron. Carbon can therefore bind with four hydrogen atoms. The carbon-carbon bond is also very important in hydrocarbon chains. Sometimes a double bond can form (the equivalent of sharing two electrons).

13

Explain the condensation which happens on your windows on a cold day.

When condensation happens on your windows on a cold day, water vapour in the air has changed state and settled on a window as liquid. The water vapour has been removed from the air.

14

When does a condensation reaction occur? And what can this allow?

A condensation reaction occurs when two molecules are joined together with the removal of water. In the same way, two molecules can be split apart with the addition of water.

15

What is a hydrolysis reaction?

When water is split by a condensation reaction.

16

When do almost all condensation reactions happen?

Almost all condensation reactions happen in the same way, when two OH- groups react together. The reaction involves the breaking and formation of covalent bonds.

17

Describe what is added in hydrolysis and taken away in condensation reactions.

H2O is added in hydrolysis and a covalent bond is broken. H2O is removed in condensation. A new covalent bond is formed. In both hydrolysis and condensation reactions the OH groups of molecule 1 and molecule 2 are close to each other.

18

Name the type of molecule, monomer, and polymer that contain C, H and O.

Molecule; Carbohydrate Monomer; Monosaccharides - e.g. glucose Polymer; Polysaccharides e.g. Starch

19

What is responsible for linking and splitting apart biological molecules in living things.

Condensation and hydrolysis reactions.

20

The units which are linked together in condensation reactions are called what?

Monomers

21

What happens when two monomers join together?

They form a dimer.

22

What happens when lots of monomers join together?

They form a polymer.

23

Name the type of molecule, monomer, and polymer that contain C, H, O, N, S

Molecule; Protein Monomer; Amino acids Polymer; polypeptides and proteins.

24

Name the type of molecule, monomer, and polymer that contain C, H, O, N, P

Molecule; Nucleic acid Monomer; Nucleotides Polymer; DNA and RNA

25

How much of the human body do hydrogen and carbon make up?

Hydrogen atoms make up 60% of the atoms in the human body. Carbon atoms make up 11% of the atoms in the human body.

26

What does does water consist of?

Two hydrogen atoms, each covalently bonded to one oxygen atom.

27

Why is water polar?

Because the oxygen atom has a greater number of positive protons in its nucleus, this exerts a stronger attraction for the shared electrons. This means the oxygen atom becomes slightly negative, and the hydrogen atoms become slightly positive. When this happens, we say the molecule is polar.

28

On a water molecule are the hydrogen positive or negative?

Positive end (poles) of molecule.

29

On a water molecule are the oxygen positive or negative?

negative end (pole) of molecule.

30

What is a hydrogen bond?

A weak interaction which happens wherever molecules contain a slightly negatively charged atom bonded to a slightly positively charged hydrogen atom.