Chapter 2

Question 1

What is matter?

Answer 1

Matter is anything that takes up space and has mass
can exist as a solid, liquid, or gas
composed of elements
Main elements of living organisms: carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur

Question 2

Atomic Theory

Answer 2

states that elements consist of atoms

Question 3

Atomic symbol

Answer 3

name of the atom or element

Question 4

subatomic elements

Answer 4

Neutrons - neutral charge, found in nucleus
Protons - positive charge, found in nucleus
Electrons - negative charge - found outside of nucleus moving in orbitals

Question 5

Mass number

Answer 5

number of protons + neutrons

Question 6

Atomic number

Answer 6

same as the number of protons
also gives numbers of electrons if an atom is electrically neutral

Question 7

Isotopes

Answer 7

atoms of the same element that differ in the number of neutrons
same number of protons but different number of neutrons
unstable and may decay, emitting radiation

Question 8

Arrangement of elements in an atom

Answer 8

electrons constantly moving
for atoms up to number 20, 2 electrons fill first shell and 8 electrons fill each additional shell
the outermost shell is most stable with 8 electrons - octet rule

Question 9

Molecule

Answer 9

group of atoms bonded together

Question 10

compound

Answer 10

molecule contained atoms of more than one element

Question 11

2 types of bonds

Answer 11

ionic - attraction between opposite charges, when atoms transfer electrons from 1 another, ex: NACL

covalent - sharing electrons to complete outer shell,
- double covalent - 2 atoms share 4 electrons; double bonds are stronger than single bonds
Ex: CH4

Question 12

Reactants

Answer 12

molecules that participate in reactions

Question 13

Products

Answer 13

molecules formed by reactions

Question 14

Chemical Formulas and reactions

Answer 14

equation is balanced if the same number of each type of atom occurs on both sides of the arrow
Ex: 6CO2 + 6H2O –> C6H12O6 + 6O2

Question 15

structure of water

Answer 15

Polar covalent bond - atoms do not share electrons equally
Hydrogen bond is weak

Question 16

Properties of water

Answer 16

Solvency, cohesion and adhesion, high surface tension, high heat capacity, high heat of vaporization, varying density

Question 17

Solvency

Answer 17

Due to polarity and H-bonding, water dissolves many substances
hydrophilic - molecules attracted to water
hydrophobic - molecules not attracted to water

Question 18

Cohesion and Adhesion

Answer 18

cohesion - ability of water molecules to cling to each other due to hydrogen bonding
adhesion - ability of water molecules to cling to other polar surfaces
allows water to be an excellent water transport system

Question 19

High surface tension

Answer 19

water molecules cling more tightly to each other than to the air above
mainly due to hydrogen bonding

Question 20

heat high capacity

Answer 20

many hydrogen bonds linking water molecules allow water to absorb heat without greatly changing its temperature
temperature of water rises and fall slowly
takes a great deal of energy to break H bonds for evaporation

Question 21

varying density

Answer 21

water expands as it freezes
ice acts as an insulator

Question 22

Acids and Bases

Answer 22

acidic solutions (<7) - acids release hydrogen ions or take up hydroxide ions
ex: lemon juice, vinegar, coffee
basic solutions (>7)- take up hydrogen ions or release hydroxide ions
ex: milk of magnesia, ammonia

Question 23

Buffers and pH

Answer 23

chemical or combinations of chemicals that keeps pH within normal limits
resists pH change by taking up excess hydrogen ions or hydroxide ions