Chem Quiz 4 (contains ch4 oxidation state assignments and redox reactions and ch5 thru slide 33)
Assign the oxidation state for Al: Al2O3,
+3
Assign the oxidation state for Mn: MnO4-
+7
Assign the oxidation state for Fe : Fe3O4
+8/3
Assign the oxidation state for H: NaH
-1
Assign the oxidation state for O2: H202
-1
if 0.473 g Mg reacts with excess hydrochloric acid, what volume of H2(g) will be produced if its measured at 753 mm and 23 degrees C Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g)
.477L
Assign the oxidation state: P4
0
The oxidation state (OS) of an individual atom in a free element is 0.
1
a sample of oxygen gas at 0.500 atm and 0 C occupies the volume of 11.2 L. What volume will the gas occupy at 6.00 atm and room temperature (25C)
1.02L
an experiment shows that a 0.495g of an unknown gas occupies 127mL at 98 degrees C and 754 torr pressure. Calculate the molar mass of the gas.
1.20x10^2g/mol
what is the density of oxygen gas (O2) at 298K and 0.987 atm?
1.29 g/L
a balloon is filled with hydrogen to a pressure of 1.35 atm and has a volume of 2.54 L. if the temperature remains constant what will the volume be when the pressure is increased to 2.50 atm?
1.37 L
a sample of gas is inside a 1.0L flask attached to a mercury manometer. Initially, the flask is 0 degrees C and 1 atm. What is the pressure of the gas if the sample is heated to 100 degrees C?
1.37 atm
The total of the OS in all atoms in i. Neutral species is 0. ii. Ionic species is equal to the charge on the ion.
2
In there compounds, the alkali metals and the alkaline earths ALWAY have OS of +1 and +2 respectiviley
3
In compounds, the OS of fluorine is always -1
4
the decomposition if sodium azide, NaN3 at high temperatures produce N2(g). together with the pessary devices to initiate the reaction and trap the sodium metal formed, this reaction is used in air-bag safety systems. what volume of N2(g), measures at 735 mm Hg and 26 degrees C, is produced when 70.0 g NaN3 is decomposed? 2 NaN3(s)--> 2 Na(l) + 3 n2(g)
41.1L
In compounds, the OS of hydrogen is usually +1
5
In compounds, the OS of oxygen is usually -2
6
what volume would 1.58 X 10^23 molecules of methane gas occupy at 15 degrees C and a pressure of 735 mm Hg?
6.41L
In binary (two-element) compound with metals: i. Halogens have OS of -1 ii. Group 16 have OS of -2 iii. Group 15 have OS of -3
7
calculate the pressure (in atm) of a 35.0 g sample of nitrogen gas in a 3.3 L container at 23 degrees C
9.2 atm
P*V =
constant
atmospheric pressure
decreases with altitude do to decreased "density" of gas molecules
gases have much lower _____ than solids or liquids
densities
pressure (Pa) =
force(N)/Area(m^2)
Amonton's law
gas pressure is directly proportional to kelvin temperature
more particles, more frequent and less area all give
higher pressure
newton =
kg * m/s^2
Oxidized reactant will...
loose e' Oxidation State increases REDUCING AGENT
Force =
mass * accel
Daltons law of partial pressures
pressure contribution of a gas within a mixture
unless O2 or H2 are in the equation, H & O
rarely change states
Acid/base and precipitation reactions rarely involve
redox
combustion always involves
redox
Stoichiometry factors
relate gas quantities to quantities of other reactants or products
Ideal gas eq. relates
the amount of gas (n) to volume (V), temperature (T) & pressure (P)
the difference in mercury height represents..
the gas pressure vs. atmospheric pressure
the pressure exerted by a liquid depends on
the height of the column of liquid. the density of the column of liquid
charle's law
the volume of a gas is directly proportional to Kelvin temperature and extrapolates to zero at zero Kelvin
Avogadro Law
the volume of a gas is directly proportional to the number of moles at low pressures
Boyles law
the volume of a gas is inversely proportional to applied pressure
gases mix
with any other gases, the are "miscible"
G.E.R
Gain Electron = Reduction
Reduced reactant will...
Gain e' Oxidation State decreases OXIDIZING AGENT
A sampl.e of KCLO3 is heated and decomposes to produce solid KCL and O2 gas. The gas is collected by water displacement at 25 degrees C. The total volume of the collected gas is 229 mL at an atmospheric pressure of 754 torr. what mass of KCLO3 must have decomposed? note: P(H20) at 25 C = 23.8 mm Hg
KClO3 = 0.735g
L.E.O
Loose Electrons = Oxidation
what does "STP" conditions mean
P=1atm, T=0 degrees C; for any ideal gas
at 25 degreesC a 1.0 L flask contains 0.35 moles of nitrogen, 0.15 moles of oxygen and 0.20 moles of ammonia. A. what is the partial pressure of each gas? B. What is the total pressure in the flask? C. What is the mole fraction of each?
Pn2 = 8.56 atm Ptotal = 17.1 Xn2 = .50 Xo2 = .21 Xnh4 = .29
Parameters Affecting Gases
Pressure, Volume, Temperature, Number of Moles
gas volume changes with
Temperature and pressure
