chemistry

Question 1

what are the difference between ion and atoms?

Answer 1

ions have charges 3+, 2-, etc
atoms have no charge + or -

Question 2

what are atoms?

Answer 2

the smallest particles, which characterize as chemical elements

Question 3

what is dalton’s theory?

Answer 3

billiard ball model
- all matter is made up of atoms, that are solid and uniform spheres
- atoms can join together which other elements to make compounds

Question 4

what is thompson’s theory?

Answer 4

raisin-bun model
- discovered every atom contains electrons
- are embedded in a cloud of positive charge

Question 5

what is rutherford’s theory?

Answer 5

solar system model
- discovered all atoms have positive nucleus, contains protons
- electrons rotate around the nucleus

Question 6

what is bohr’s theory?

Answer 6

energy level model
- electrons associate with specific energy levels

Question 7

what are isotopes?

Answer 7

atoms of the same element that have the same protons but different neutrons

ex). Carbon-12 = mass 12 || protons 6
carbon-13 = mass 13 || protons 6

Question 8

when are ions most stable?

Answer 8

are most stable when gaining or losing electrons from outer rings

Question 9

cations

Answer 9

lost electrons to become positive

Question 10

anions

Answer 10

gained electrons to be negative

Question 11

molecular

Answer 11

non-metal + non-metal
- cannot be conducted by H20

Question 12

ionic

Answer 12

metal + non-metal
- can be conducted by H20

Question 13

naming non-metals

Answer 13

• use Latin prefixes
• use -ide at end

*metals do not use these

Question 14

reactions

Answer 14

physical change = solid > liquid
chemical change = C + O = CO2
energy change = endothermic & exothermic

Question 15

endothermic

Answer 15

absorb heat (cold)

Question 16

exothermic

Answer 16

release heat (hot)

Question 17

C(s) + O 2(g) → CO 2(g)

Answer 17

formation

Question 18

AB → A + B

Answer 18

decomposition

Question 19

Zn + 2HCl -> ZnCl2 + H2

Answer 19

single replacement

Question 20

BaCl2 + K2CO3 → BaCO3 + 2KClA

Answer 20

double replacement

Question 21

HNO 3(aq) + Ba(OH) 2(aq) → H 2O(ℓ) + Ba(NO 3) 2(aq)

Answer 21

neutralization (always have H2O or HOH)

Question 22

CH4 (g) + 02 (g) → CO2 (g) + H2O (g)

Answer 22

hydrocarbon combustion

Question 23

ionic naming

Answer 23

• cross and drop
• write charges of each element
• reduce to lowest terms

ex). Mg 2+ & Cl - → MgCl2

Question 24

ionic compounds

Answer 24

1). crystal lattice: solid state
2). solid state does not conduct electricity
3). high melting point: needs lots of energy to break bonds

Question 25

molecular compounds

Answer 25

1) low melting point: does not need much energy to melt
2). non-electrolytes: does not conduct electricity
3). do not decompose into other elements

Question 26

acid and bases

Answer 26

• only dissolved in water
• always written and aq
• both conduct electricity

Question 27

acid rules

Answer 27

• produces H+ (hydrogen)
• turns limtis paper red
• lower than 7 pH level

Question 28

base rules

Answer 28

• produces OH- (hydroxide)
• turns limtis paper blue
• higher than 7 pH level

Question 29

law of conservation of energy

Answer 29

“energy can be converted from one form to another, but total energy remains the same.”

Question 30

physical change

Answer 30

change in substance where chemical compositions stays the same

Question 31

chemical reactions

Answer 31

creates new reactions
ex). C + O → CO2