Unit 1 Chemistry Of Life

Question 1

What percentage of living matter is made up of carbon, hydrogen, oxygen, and nitrogen?

Answer 1

96%

Carbon, hydrogen, oxygen, and nitrogen are the four essential elements of life.

Question 2

What are the remaining 4% of essential elements for life?

Answer 2

Calcium, phosphorus, potassium, sulfur

These elements are crucial for various biological functions.

Question 3

What mnemonic can help remember important biological elements?

Answer 3

SPONCH CaFe or CHNOPS

These mnemonics represent essential biological elements.

Question 4

What is the result of nitrogen deficiency in plants?

Answer 4

Yellowing of leaves

Question 5

What is the result of iodine deficiency in organisms?

Answer 5

Enlarged thyroid gland

Question 6

What are molecules composed of?

Answer 6

Groups of atoms bonded together

Question 7

What is the significance of molecular shape in biological interactions?

Answer 7

Molecules recognize and interact with each other with specificity based on molecular shape

Question 8

What are the starting molecules in a chemical reaction called?

Answer 8

Reactants

Question 9

What are the final molecules in a chemical reaction called?

Answer 9

Products

Question 10

What is chemical equilibrium?

Answer 10

Reached when the forward and reverse reaction rates are equal

Question 11

What is the biological medium on Earth?

Answer 11

Water

Question 12

What percentage of most cells is made up of water?

Answer 12

70-95%

Question 13

What property of water allows it to form hydrogen bonds?

Answer 13

Polarity

Question 14

What are the four properties of water that facilitate life?

Answer 14

• Cohesive behavior
• Ability to moderate temperature
• Expansion upon freezing
• Versatility as a universal solvent

Question 15

What is cohesion in relation to water molecules?

Answer 15

Hydrogen bonds hold water molecules together

Question 16

What is surface tension?

Answer 16

A measure of how hard it is to break the surface of a liquid

Question 17

What is water’s high specific heat?

Answer 17

The amount of heat needed to change the temperature of 1 gram of water by 1ºC

Question 18

What is a solution?

Answer 18

A liquid that is a homogeneous mixture of substances

Question 19

What is a solvent?

Answer 19

The dissolving agent of a solution

Question 20

What is a hydrophilic substance?

Answer 20

A substance with an affinity for water

Question 21

What is a hydrophobic substance?

Answer 21

A substance that does not have an affinity for water

Question 22

What are van der Waals interactions?

Answer 22

Weak attractions between molecules or atoms due to fleeting charge differences

Question 23

How is molarity defined?

Answer 23

Molarity (M) = mols/ liter

Question 24

What happens to water molecules that leads to acidic and basic conditions?

Answer 24

Dissociation of water molecules

Question 25

What is an acid?

Answer 25

Any substance that increases the H+ concentration of a solution

Question 26

What is a base?

Answer 26

Any substance that reduces the H+ concentration of a solution

Question 27

What does the pH scale measure?

Answer 27

The relative concentration of hydrogen ions in a solution

Question 28

What is the pH of neutral solutions?

Answer 28

pH 7

Question 29

What are buffers?

Answer 29

Substances that minimize changes in concentrations of H+ and OH- in a solution

Question 30

What is acid precipitation?

Answer 30

Rain, snow, or fog with a pH lower than 5.6

Question 31

What causes acid precipitation?

Answer 31

Mixing of different pollutants with water in the air

Question 32

What is ocean acidification?

Answer 32

CO2 from the atmosphere dissolves in water to form carbonic acid

Question 33

What is the dilution equation used for?

Answer 33

To change the concentration of a solution

Question 34

Fill in the blank: A solution with two moles of solute dissolved in 1 L of solvent has a molarity of _______.

Answer 34

2M

Question 35

True or False: Most biological fluids have pH values in the range of 6 to 8.

Answer 35

True