chemical reactions (everything) Flashcards
what is a chemical reaction?
a process that leads to the chemical transformation of one set of chemical substances to another.
two types of changes + their definition
phyical: same identity
chemical: formation of new substance
descriptors of chemical changes (examples: 4)
1) exploding
2) Burning
3) Decomposing
4) Oxidizing
Obserable evidence of chemical changes (5)
- Preciptate (a solid form of 2 solutions, usually cloudy and has to be insoulable)
- Colour change
-Smell change - Gases
-Temp
why is changes in energy not a definite indicator
what is change in energy?
–> Physical changes can have changes in energy: (Ie boiling, melting, dissolving)
Release/absorbtion of eneergy: Light,
what is a catalyst?
–> substance that makes a chemical reaction occur faster w/o itself being consumed in the reaction
what is synthesis?
two reactants combining t make a larger more complex pattern.
3 types of synthesis reactions:
1) metal + nonmetal –> ionic compound
2) metallic oxide + water –> base (hydroxide)
3) nonmetal oxide + water –> acid (usually an oxyacid)
synethsis memorization (acids)
3) nonmetal oxide + water –> acid (usually an oxyacid)
CO2 ?
N2O3 ?
SO2 ?
SO3?
P2O5 ?
CO2 + H2O –> CARBONIC ACID CO3
N2O3 + H20 –> HNO2 (NITROUS ACID)
SO2 + H2O –> H2SO3 (SULFOURUS ACID
SO3 + H2O –> H2SO4 (SULFURIC ACID)
PSO5 –> H3PO4 (PHOSPHIC ACID)
what is decompostion?
a chemical reaction, one large compound breaks down to smaller substances:
AB –> A + B
8 types of decomposition reactions?
1) compound –> element + element (binary compounds) (can be both molecular or ionic)
2) nitrate (NO3) –> nitrite (NO2) + oxygen
3) Chlorate (CLO3) –> Chloride (CL) + O2
4) Carbonates (CO3) –> Oxide + CO2
5) Bicarbonate (HCO3) –> Carbonate (CO3) + Carbon Dioxide + Water
6) Hydrates —> Compound + Water
7) Hydroxide –> Metal Oxide + Water
8) Acids —> Nonmetal oxide + Water
Decomposition of acids (Memorization)
H2CO3 –>
H2SO4 —>
H2SO3 —>
H3PO4 —>
HNO3 —>
H2CO3 –> CO2 + H2O
H2SO4 —> SO3 + H20
H2SO3 —> SO2 + H2O
H3PO4 —> P2O5 + H2O
HNO3 —> NO2 + O2 + H2O
What is single displacement? (And what does it use?)
An element displaces another in a compound, producing a new compound and a new element.
The element that displaces, must be more reactive that the element it wants to replace.
Metals: usage of the activity series. (Higher on the reactivity series = more reactive) (First bracket = can relace H in water) (Second bracket = must replace hydrogen in acids)
Nonmetals: Use of periodic trends. (F, Cl, Br, I…) (Halogens)
When does no reaction happen?
Single displacement: When the element that displaces another is not reactive enough
Double displacement: When a precipitate, water or gas is not formed
(2 elements are both aqeous, therefore no reaction happened)
what is double displacement?
elements in two compounds displace each other to form 2 new compounds.
AB + CD —> AD + CB
When does double displacement form a precipitate, water or gas?
Precipitate (what is special with NH4 and OH)
Precipitate: 2 solutions forming a solid (usuage of the soulability table)
(NH4OH DOES NOT EXISIT therefore: NH4CL + KOH –> NH3 (g) + H2O (l) + KCL (s)
Neutralization reactions form water:
(ACID + BASE)
(ACID + Metal oxide)
—> Forms water and a salt
(The ionic compound is always aqeous)
Gas formation:
1) Carbonates
CO3 + acids –> Salt + CO2(g) + WATER (l)
2) Sulfite
SO3 + Acids –> Salt + SO2(g) + H2O (l)
3) Sulfide
(__S) + Acid –> Salt + H2S(g)
which acids immediatly dissociate after being formed?
1) carbonic acid (H2CO3 –> CO2 + H2O)
2) Sulfurous acid (H2SO3 –> SO2 + H2O)
what does C + 2H2 –> usually form?
CH4
(Methane)
What is combustion/burning?
WHat is fuel?
___ + O2
-> Anything can burn if it is hot enough and has sufficent oxygen
Fuel is a hydrocarbon (CH)
What is complete combustion?
Produces CO2 (g) + H2O(g)
-> Hot blue flames
-> Excess amount of oxygen (outside, etc)
“Fuel lean”
What is incomplete combustion?
Produces CO(g) + H2O + C(s) + CO2(g)
C is soot
->Yellow flame
-> Limited amout of oxygen
->Cooler than complete combusition
Usually burning in an inclosed spaced
Produces a black smoke (indicating that fuel is not burning efficently)
“Fuel rich”
Why is incomplete combustion bad?
–> Only a portion of energy is being used
–> Soot particles are toxic
–> CO is toxic, colourless, testeless, odourless
what is a acidic oxide?
-> hydrogen ions when dissolved when mixed w water
-> conducts electrcity
-> tastes sour
-> turns litmus paper red
what is a basic oxide?
-> red litmus paper blue
-> hydroxide ions when mixed with water
-> conducts elecricity
-> bitter
