Water Chemistry

Question 1

Everything is composed of what?

Answer 1

Matter

Question 2

What is an element?

Answer 2

purest form of matter, matter which cannot be divided into more than one substance

Question 3

Matter occurs in three states? What are they?

Answer 3

-solid (iron), liquid (mercury), gas (oxygen)
-getting them to change states = requires energy
-Water → exists in all three forms of matter in the same place at the same time

Question 4

atom

Answer 4

the smallest division of an element which retains all the properties of that element

Question 5

chemistry

Answer 5

studies of types of matter along with how they interact

Question 6

the three parts of an atom are…?

Answer 6

protons, neutrons, and electrons

Question 7

protons

Answer 7

positively charged particles

Question 8

neutrons

Answer 8

particles with no charge

Question 9

electrons

Answer 9

negatively charged particles that exist around the nucleus of the atom

Question 10

what do protons and neutrons do togeather in an atom?

Answer 10

together protons + neutrons make up the atoms nucleus

Question 11

What are orbitals?

Answer 11

-spaces electrons occupy
-form orbitals/layers or shells around the nucleus → each layer can only have a certain number of electrons in the shell
- 1st orbital around nucleus of any atom can hold up to 2 electrons
- 2nd orbital → can hold up to 8 electrons
- 3rd orbital → can hold up to 8

Question 12

Where do reactions happen?

Answer 12

-outermost orbital → valence electrons → those in outer most layer → this is where reactions happen

Question 13

What happens when you change the number of protons in an element?

Answer 13

-hard to change # of protons → if you change number of protons you have changed what the element is

Question 14

Valence electrons

Answer 14

those in the outermost layer/shell

Question 15

Electrically neutral

Answer 15

-number of protons equals the numbers of electrons
-pluses and minuses equal each other
-does not mean it is necessarily stable, can be reactive

Question 16

how does one read the periodic table of elements

Answer 16

-has all chemical symbols of all elements
-number in top corner → how many protons + electrons the element: atomic number***

Question 17

what is a molecule?

Answer 17

2 or more atoms may combine to form this
-a compound is a substance made of molecules from 2 or more elements in set proportions

Question 18

What are ionic bonds?

Answer 18

one atom donates or accepts an electron from another atom
-electrons = transferred from one atom to another
-creates ions → charged particle/atoms
-can be positively or negatively charged
-Atoms prefer to have a full orbital of electrons in their outermost shell
-easier to pick one or two up then get rid of seven
ex. Salt (NaCl)

Question 19

What are covalent bonds?

Answer 19

• Electrons are shared between different atoms
  -ex: water -> hydrogen atoms share electrons with oxygen → each hydrogen brings its electron to the oxygen that wanted to have a full compliment of 8 electrons in its outer shell
• have slightly negative end on oxygen end + slightly positive end on hydrogen side –> polar covalent bonds hold water together

Question 20

Hydrogen Bonds

Answer 20

-form between slightly negative oxygen end of one molecule and the slightly positive hydrogen end of a different water molecule
-give water unique characteristics such as
1. being universal solvent
2. Cohesion + Adhesion
3. has a high specific heat and a high heat of vaporization
4. less dense as a solid than as a liquid (ice floats)

Question 21

Water is the universal solvent means what?

Answer 21

-it will dissolve most other polar or ionic compounds
-molecules = very small → wiggle in to subatomic spaces
- water = stable + polar
- as a molecule → stays as it is
- polar → slight positive + negative end → things held together by ionic/polar bonds dissolve well in water
- polar nature makes it good solvent
- bad at dissolving lipids → grease/fat

Question 22

What is Cohesion and Adhesion?

Answer 22

-sticks to itself → cohesion
-sticks to other things → adhesion
- another structure with polarity → water → sticks to it
- Water molecules cling to other molecules through hydrogen bonds
- gives water a high surface tension → water molecules hold on to themselves tightly → make a bubble top

Question 23

What does water having a high specific heat mean?

Answer 23

-hard to make water change states → takes/releases a lot of energy
-High specific heat → the amount of heat required to raise the temperature of a specific amount of a substance 1 Celsius
-water = hight heat capacity of any liquid except ammonia → takes a lot of energy to make water change its state
- Lots of energy required to break hydrogen bonds before molecules begin to move faster and temperature can increase
- water= good insulator → stores heat
- get water to change state → bust up hydrogen bonds → water resists that state change

Question 24

What does water’s high heat of vaporization mean?

Answer 24

• heat necessary to convert liquid water to water evaporation
  
  • water → good coolant
  • same amount of heat is released when water condenses from vapor to liquid
  • heat transfer of the earth is dependent on this

Question 25

Why does Ice float?

Answer 25

–
- most things when they get from solid to liquid get more dense → not water
- ice floats because of hydrogen bonds
- liquid water → molecules = packed in tight
- chill water → molecules pack in tighter → become denser
- once 0 degrees is hit → change state to solid water → when state change is made → spread themselves out at fixed intervals
- due to bond angle of molecules → have to space out in frozen form at set intervals
- spaced out farther apart at set intervals → effect → ice floats → fewer molecules per liquid area
-ecologically important because of the mixing of nutrients