U1L2 Flashcards

1
Q

What forms the atomic nucleus?

A

Neutrons and protons with electrons forming a cloud around the nucleus

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2
Q

What are covalent bonds?

A

Sharing of a pair of valence electrons by 2 atoms. In a covalent bond, shared electrons count as part of each atom’s valence shell

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3
Q

What is electronegativity?

A

An atom’s attraction for the electrons in a covalent bond. The more electronegative an atom, the more strongly it pulls shared electrons toward itself

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4
Q

Differentiate between polar and non polar covalent bonds?

A

Non polar covalent bonds are where atoms share electrons equally and polar covalent bonds are when one atom is more electronegative and the atoms do not share electrons equally

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5
Q

Ch4 would have which type of bond?

A

Non polar covalent bond

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6
Q

Is a water molecule polar or non polar

A

A water molecule is polar
- unequal sharing of electrons causes a partial positive or negative charge for each atom of a molecule

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7
Q

What are ionic bonds?

A

When atoms strip electrons from their bonding partners, both atoms have charges. A charged atom or molecule is called an ion

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8
Q

What are hydrogen bonds?

A

A hydrogen bond forms when a hydrogen atom covalently bound to an electronegative atom is also attracted to another electronegative atom. In living cells, electronegative partners are usually oxygen or nitrogen

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9
Q

Explain Van der waal’s interactions

A

Attractions between molecules that are close together as a result of asymmetrically distributed electrons in molecules or atoms which can result in “hot spots” of positive or negative charges

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10
Q

Why is molecular shape important?

A

Molecules recognize, interact and respond to each other based on molecular shape. Molecules with similar shapes can have similar biological effects (naturally produced endorphins and morphine)

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11
Q

Define chemical reactions

A

Making and breaking of chemical bonds. The starting molecules of a chemical reaction are called reactants and the final molecules are called products

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12
Q

Define photosynthesis and the equation

A

Important chemical reaction where sunlight provides energy that is used to convert carbon dioxide and water to glucose and oxygen
6CO2 + 6H2O = C6H12O6 + 6O2

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13
Q

Water is the…..

A

Biological medium of earth. Due to climate change, the ratio of liquid water to ice is changing affecting organisms in the arctic

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14
Q

How many hydrogen bonds can one water molecule participate in and why?

A

4
Regions of neighbouring water molecules with opposite partial charges are attracted to each other forming hydrogen bonds. Each water molecule can hydrogen bond to several others

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15
Q

Why is the oxygen atom important in a water molecule?

A

Water is a polar molecule due to the highly electronegative oxygen atom with the overall charge being unevenly distributed. Polarity allows water molecules to form hydrogen bonds with each other

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16
Q

What are the 4 emergent properties of water that contribute to earth’s suitability for life?

A

Cohesive behaviour
Ability to moderate temperature
Expansion upon freezing
Versatility as a solvent

17
Q

Explain the cohesion of water molecules

A

Hydrogen bonds hold water molecules together through cohesion which helps transport water against gravity in a plant

18
Q

Define surface tension

A

Measure of how hard it is to break the surface of a liquid. Water has an unusually high surface tension due to hydrogen bonding between the molecules at the air- water Interface and to the water molecules below

19
Q

Explain moderation of temperature by water

A

Water absorbs heat from warmer air and releases stored heat to cooler air. Water absorbs or releases a large amount of heat with little change in its own temperature

20
Q

What is specific heat?

A

Amount of heat that must be absorbed or lost for 1g of a substance to change temp

21
Q

Why does water have high specific heat?

A

Due to hydrogen bonding. Heat absorbed when hydrogen bonds break and heat is released when hydrogen bonds form. The high specific heat of 1 cal/g Celsius minimizes temperature fluctuations to within limits that permit life

22
Q

Why does ice float on liquid water?

A

Hydrogen bonds in ice are more “ordered” making ice less dense

23
Q

Explain hydrophilic and hydrophobic substances

A

Hydrophilic substance has an affinity for water while hydrophobic substance does not have an affinity for water

24
Q

Explain the process of ocean acidification

A

CO2 dissolved in sea water forms carbonic acid. As seawater acidifies, H+ ions combine with carbonate ions to produce bicarbonate. Carbonate is required for calcification (production of calcium carbonate) by many marine organisms such as corals

25
Q

Why is carbon important

A

Living organisms consist of mostly carbon based compounds since carbon is able to form large, complex and diverse molecules such as proteins, DNA and carbohydrates

26
Q

What is electron configuration?

A

Key to an atom’s characteristics since it determines kinds and number of bonds an atom will form with other bonds
(Carbon can form 4 covalent bonds)

27
Q

What shape does a carbon single bonded to 4 other atoms have?

A

Tetrahedral shape

28
Q

What are the “building codes” of living molecules?

A

Hydrogen, oxygen, nitrogen and carbon

29
Q

Define hydrocarbons

A

Organic molecules consisting of only carbon and hydrogen. Many organic molecules such as fats have hydrocarbon components. Hydrocarbons can undergo reactions that release a large amount of energy

30
Q

Define isomers and the 3 types of isomers

A

Compounds with same molecular formula but different structures and properties
Structural isomers: have different covalent arrangements
Cis-trans isomers: have the same covalent bond by differ in spatial arrangements
Enantiomers: mirror images of each other

31
Q

Why is it dangerous to not understand the function of an isomer of a molecule?

A

One isomer might be safe for use while the other isomer could cause serious damage to the body

32
Q

Define ATP and its importance

A

Adenosine triphosphate is the primary energy transferring molecule in the cell
ATP consists of an organic molecule called adenosine attached to a string of 3 phosphate groups. ATP stores potential energy that can be released in a reaction with water and used by the cell