chemistry Flashcards
what are the difference between ion and atoms?
ions have charges 3+, 2-, etc
atoms have no charge + or -
what are atoms?
the smallest particles, which characterize as chemical elements
what is dalton’s theory?
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
what is thompson’s theory?
raisin-bun model
- discovered every atom contains electrons
- are embedded in a cloud of positive charge
what is rutherford’s theory?
solar system model
- discovered all atoms have positive nucleus, contains protons
- electrons rotate around the nucleus
what is bohr’s theory?
energy level model
- electrons associate with specific energy levels
what are isotopes?
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
when are ions most stable?
are most stable when gaining or losing electrons from outer rings
cations
lost electrons to become positive
anions
gained electrons to be negative
molecular
non-metal + non-metal
- cannot be conducted by H20
ionic
metal + non-metal
- can be conducted by H20
naming non-metals
- use Latin prefixes
- use -ide at end
*metals do not use these
reactions
physical change = solid > liquid
chemical change = C + O = CO2
energy change = endothermic & exothermic
endothermic
absorb heat (cold)
exothermic
release heat (hot)
C(s) + O 2(g) → CO 2(g)
formation
AB → A + B
decomposition
Zn + 2HCl -> ZnCl2 + H2
single replacement
BaCl2 + K2CO3 → BaCO3 + 2KClA
double replacement
HNO 3(aq) + Ba(OH) 2(aq) → H 2O(ℓ) + Ba(NO 3) 2(aq)
neutralization (always have H2O or HOH)
CH4 (g) + 02 (g) → CO2 (g) + H2O (g)
hydrocarbon combustion
ionic naming
- cross and drop
- write charges of each element
- reduce to lowest terms
ex). Mg 2+ & Cl - → MgCl2
ionic compounds
1). crystal lattice: solid state
2). solid state does not conduct electricity
3). high melting point: needs lots of energy to break bonds
molecular compounds
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
acid and bases
- only dissolved in water
- always written and aq
- both conduct electricity
acid rules
- produces H+ (hydrogen)
- turns limtis paper red
- lower than 7 pH level
base rules
- produces OH- (hydroxide)
- turns limtis paper blue
- higher than 7 pH level
law of conservation of energy
“energy can be converted from one form to another, but total energy remains the same.”
physical change
change in substance where chemical compositions stays the same
chemical reactions
creates new reactions
ex). C + O → CO2
