Post on 13-Jan-2016
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ReleasedQuestions
ChemistryCA Standards Test
ReleasedQuestions
Measure temperature
Measure heat
Measure color of light
Observation Hypothesis Theory Law
(The Atomic Theory)A well-accepted idea.
Refer to yourPeriodic
Table
Chemical Families act the same.
Alkali metals (Li, Na, K…) are the easiest atoms to pull an electron off of.
Noble gases arethe hardest to pull anelectron off of.
Family 6 has6 valence electrons.
Most particles missed the nucleus
A few alpha particles hit something small and very dense!
single-atom
Cl2
F2
He
N2
The Diatomic Elements:
HONClBrIFor
BrINClHOF
The examples contain C, N, H, & O
nonmetals with nonmetals
Use your Periodic TableSame family as Silicon
Volume decreases x2Pressure increases x2
At STP, 1.0 mole = 22.4 L
So, half a mole = 11.2 L
The answer is STP (T=273 K & P=1.00 atm)
K -273 = ºC423 - 273Remember, no calculator…
The answer is NOT negative.
And
423 – 273 696!
These mix very well so you can dissolve alcohol in water or water in alcohol!
Hint: Read the question before looking at the table of information…
“Like Dissolves Like”
Polar solutes dissolve in polar solvents.
Nonpolar solutes dissolve in nonpolar solvents.
Polar and nonpolar do not mix (e.g. oil & H2O).
A Proportion!If 36.2 g dissolves in 100 g of H2O,How much dissolves in 50 g of H2O?
Liters 5
moles ? M 2.0
Hint: If the math confuses you, try each answer until you find the right one.
ppm is related to %
100 solvent
solute %
1,000,000 solvent
solute ppm
1,000,000 1,000
g 332
Heat = mass x (change in Temp) x specific heat
= 30 g (40.0ºC) (0.4 J/g ºC) = 30 (4)(4) J = 120 x 4 = 480 J
From the formula sheet:
HCl + NaOH H2O + NaCl (salt water)
Salt water is neutral!
Our’s looked more like this:
Which answer is NOT an electrolyte?
Nope… bases are slippery.
Nope… acids + bases form salts.
Nope… they become less acidic… they get neutralized!
Acidic = Low pH
Basic = High pH
Le Châtelier's Principle
Reactants Products
Increase pressure =
decrease in volume
Not enough room… switch to the side that takes up less room
(fewer moles of gas)
21
Add heat… shift left
Add liquid… no change
Shift left… make O2
Fewer moles of gas on the right. 5 2
Shift right… use up CO
No change… 2 2
Shift right… make CO2
Shift left: use up NO
H2O(l) H2O(g)
4
CH3CH2OH is C2H6O
C2H6O + 3O2 2CO2 + 3H2O
Molar mass of carbon-12:
12.00 g/mole
moles 0.5 g/mole 12
grams 6
massmolar
grams moles
Or… 12 grams = 1 mole so… 6 grams = .5 moles
Approximate:
195 g = 1 mole… so 97.6 g = .5 mole
1 mole = 6.02 x 1023 atoms… so .5 mole =
3.01 x 1023 atoms!
Look up Pt on the Periodic Table
1 mole CO2 and 2 moles H2O are formed.
Translate:
6.02 x 1023 = 1 mole
1.2 x 1024 = 2 moles
Use P.O.E.
Process
Of
Elimination
Molar Mass of CH4
12.0 + 4.0 = 16.0 g/mole
moles 6 g/mole 16
grams 96
massmolar
grams moles
Hint: Again… if the math is too much… try each answer out.
52 g Cr = 6.02 x 1023 atoms
13 g Cr = ¼ x 6.02 x 1023 atoms
= 1.5 x 1023 atoms
1 Fe2O3 = 2(55.85) + 3(16.00) = 112 + 48 = 160 grams
3 CO = 3(12.0 + 16.0) = 3(28) = 84 grams
So… 160 grams Fe2O3 is needed to react with 84 grams of CO!
6(2+16) = 6(18) = 60 + 48 = 108 grams
2(14+3) = 2(17) = 34 grams
108 g H2O 34 g NH3
so…
54 g H2O 17 g NH3
Hint: The numbers have to be simple because you won’t have a calculator.