2.2 Properties of Water

Question 1

Why is water a polar molecule?

Answer 1

1. The oxygen nucleus attracts electrons more strongly than the hydrogen nucleus (electrons go around oxygen more that hydrogen)
2. This causes electrons to be closer to the oxygen nucleus, creating a partial negative charge near the oxygen atom and a positive charge between the hydrogen atoms

Question 2

What is a hydrogen bond?

Answer 2

The attraction between a hydrogen atom with a partial positive charge and another atoms with a partial negative charge

Question 3

What leads to oxygen’s speacial properites?

Answer 3

Its polarity leads it to form multiple hydrgen bonds with other water molecules

Question 4

What are water’s special properites?

Answer 4

Univeral Solvent, Cohesion and Adhesion, Changes in density, high surface tension, and high heat capacity

Question 5

What is cohesion?

Answer 5

the attraction between molecules of the smae substance

Question 6

What creates water’s surface tension?

Answer 6

Hydrogen bonds make water very cohesive and causes water molecules to be drawn to together in drops on smooth surfaces

Question 7

What is adhesion?

Answer 7

the attraction between molecullles of different substances

Question 8

Adhesion in water causes:

Answer 8

the surface of water in a cylinder to dip slightly in the middle bedcuase adhesion between water and the glass is stronger that the cohesion between water molecules

(also leads to capillary action)

Question 9

What is a mixture?

Answer 9

a material composed of 2 or more elements or compounds that re physically mixed together but not chemically combined

ex: salt and sand mixed

Question 10

what is a solution?

Answer 10

all compounds are evely distributed

Question 11

what is the solute

Answer 11

the substance that is dissolved

Question 12

what is the solvent

Answer 12

the substance in which the solute dissoves (water)

Question 13

what is a suspension?

Answer 13

materials that don’t dissolve when placed in water but separate into pieces so small that they do not settle out

Question 14

what is pH scale?

Answer 14

measurment system to indicate the concentration of hydrogen ions in a solution

Question 15

What is an Acid

Answer 15

any compound that forms H+ ions in a solution

Question 16

What is a base?

Answer 16

a compound that produces hydroxide ions (OH-) is solutions

Question 17

What is a buffer?

Answer 17

a weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in pH

Question 18

Why are buffers important?

Answer 18

to maintain homostasis in organisims

Question 19

Hydrogen bonds are:

Answer 19

very weak

Question 20

Water is a polar molecule so it forms many:

Answer 20

hydrogen bonds

Question 21

What are common partially negative atoms involved in hydrogen bonding?

Answer 21

oxygen, nitrogen, and flourine

Question 22

How does hydrogen bonding work between water molecules?

Answer 22

The slightly postive ends of a water molecule attract the slightly negative end of another water molecule

Question 23

What is the specific heat of water?

Answer 23

4,184 joules of energy are required to raise 1 kg of water 1 degree celsius

Question 24

Why is it important for water to have a high specific heat?

Answer 24

Water is 60-70% of the body so it is resistant to ectreme temperature changes, helps to maintain homeostasis

Question 25

Living things are composed of what 2 mixtures?

Answer 25

Solutions and suspensions

Question 26

How does salt dissolve in warn water creating a solution?

Answer 26

The Na+ ions bond with the negative ends of water’s polar molecule, the Cl- ions relate to the positive end

Question 27

What pH scale is water, lemon juice, and bleach?

Answer 27

Water- neutral
Lemon Juice- acid
Bleach- base

Question 27

How does milk of magnisia help with an acidic stomach?

Answer 27

it is a base to it neturalizes the acid