Bio Test #3

Question 1

How are compounds formed?

Answer 1

Atoms interact with each other forming compounds

Question 2

Compound

Answer 2

Made of 2 or more elements in specific proportions

Ex: H2O & H2CO3

Question 3

What are compounds held together by?

Answer 3

When atoms form compounds they are held together by atomic bonds

Question 4

What are 2 types of bonds?

Answer 4

Covalent & ionic

Question 5

Covalent

Answer 5

Electrons are shared

Question 6

Ionic

Answer 6

Transfer electrons (from one atom to another)

Question 7

Why do atoms form bonds?

Answer 7

Atoms form bonds according to how electrons are arranged in their orbitals

Question 8

Noble gases

Answer 8

Atoms are chemically stable when orbitals of its highest level are filled with maximum number of electrons

Question 9

Molecule

Answer 9

The simplest part of a substance that retains all the properties of that substance

Question 10

In an ionic bond, what is done when both elements have unfilled outer orbitals?

Answer 10

They transfer electrons making them both more stable and both gain a charge that keeps them together

Question 11

Hydrogen Bond

Answer 11

Force of attraction between partially positive charge of one molecule and the partially (or full) negative charge of another molecule

Question 12

What does partially positive or negative mean?

Answer 12

Electrons turn so they are not always positive or negative

Question 13

Polar Molecules

Answer 13

Molecules with uneven distribution of charges

Question 14

How are hydrogen bonds compared to covalent & ionic?

Answer 14

Hydrogen bonds are not as strong as ionic or covalent bonds, they break more easily

Question 15

How many hydrogen bonds can form from each H2O molecule?

Answer 15

4

Question 16

How does a water molecule behave like an electromagnet?

Answer 16

Having the positive end attract a negative ion or negative end of another polar molecule and vice versa

Question 17

Why does a water molecule behave like an electromagnet?

Answer 17

Because of its polarity

Question 18

What are properties water exhibit because if its electromagnetism?

Answer 18

Transparency, adhesion, cohesion, solvent, thermal, transport medium, & medium for metabolic reaction

Question 19

Transparency

Answer 19

Light can pass through ware

Question 20

Adhesion

Answer 20

Because of water polarity, water molecules can interact with molecules of other substances. This attraction makes capillary action possible

Question 21

Capillary Action

Answer 21

Property of water to pull itself up through a small opening against the force of gravity. Important in plants to get water from the soil to the leaves

Question 22

Cohesion

Answer 22

Because of hydrogen bonds water molecules interact with other water molecules- creating surface tension which allows some animals to use it as a habitat (example: mosquito larvae, spiders can walk on it, “Jesus Lizard”

Question 23

Solvent Properties

Answer 23

Because of water polarity, water can break bonds between other substances (dissolve substance)

Question 24

Is water a universal solvent?

Answer 24

Water is a very strong solvent, but it is not a universal solven because if it were, we could not drink it, swim it, hold it in ourselves, store it in a bottle, etc. however water can break bonds between many substances such as: salt & glucose

Question 25

Thermal properties

Answer 25

Heat capacity, boiling & freezing point, cooling effect of evaporation

Question 26

Heat capacity

Answer 26

Water has a large amount of energy & is needed to raise water temperature of 1 degree Celsius. This is due to water polarity because a lot of energy is needed to break hydrogen bonds between water molecules. As hydrogen bonds break molecules move faster & this generates heat. Allowing water to be stable & use blood to move heat around the body

Question 27

Boiling & freezing point

Answer 27

Water having a high boiling point allows for water to change from liquid to gas by breaking all hydrogen bonds. When water freezes it becomes less dense because as molecules slow down, they form hydrogen bonds & spread apart. However the ice that forms at the surface of a lake/ river, creates an insulation layer that allows the water underneath not to freeze

Question 28

Cooling effect of evaporation

Answer 28

Water can evaporate at temperatures lower than boiling temp. In order for some water molecules to evaporate from the surface, hydrogen bonds need to be broken. The energy used to break the bond is taken from the water itself. Evaporation allows water to cool because When water loses energy it’s temp goes down

Question 29

Why is water a good transport medium?

Answer 29

Because of water solvent properties and how dense water is

Question 30

Transport medium

Answer 30

Because of its density water can support mass of large & small organisms which live and move in it. Also currents in water help carry nutrients, spores, & organisms from one place to the next. Water is also used in cells & organisms to transport all kinds of nutrients & molecules from one place to the next (ex: water is an important part of digestion, blood, & both vascular tissues

Question 31

Medium for metabolic reactions

Answer 31

Water is the medium in which most reactions take place & is capable of breaking bonds between compounds & once those compounds are free, they can react with other compounds. Water is not the only medium for reactions, but in most living organisms it is where most metabolic reactions occur