Show:
Stoichiometry
Eclectic
Exam 1
Exam 2
Exam 3
100
How many moles of water vapor are produced for every mole of methane consumed in the combustion reaction CH4(g) + 2O2(g) --> CO2(g) + 2H2O(g)?
2 moles
100
What volume of 2.5 M SrCl2 is needed to prepare 500.0 mL of 5.0 mM solution?
1.0 mL (2.5 M)(X mL) = (5.0 x 10^-3 M)(500.0 mL)
100
The number of ____________ distinguishes teh atoms of one element from another.
protons
100
The correct name for CuO is _______________.
Copper (II) oxide
100
The theoretical yield of aluminum oxide for a process is 155.9 g. What is the percent yield if 100.0 g of aluminum oxide were obtained?
64.14 % (100.0g/155.9g)x100
200
Most of the CO2 emitted by industrial sources comes from the combustion of fossil fuels, but some is also produced by cement manufacturing and the conversion of limestone (CaCO3) to lime (CaO): CaCO3(s) --> CaO(s) + CO2(g) How many tons of CO2 are produced per ton of lime? (1 ton = 1000 kg)
0.7848 tons CO2 1 ton CO2 . 1 kg . 44.01g CO2 . 1 mol CO2 . 1 mol CaO . 1000 g . 1000 kg . 1 ton CaO = 0.7848 tons CO2 1000 kg 1000g 1 mol CO2 1 mol CaO 56.08 g CaO 1 kg ton CaO
200
When an evacuated 63.8 mL glass bulb is filled with a gas at 295 K and 0.983 atm, the bulb gains 0.103 g in mass. Is the gas N2, Ne, or Ar? (Universal gas constant = 0.0826 L atm/K mol)
Ar (0.983 atm)(0.0638 L)=(n)(0.0826 L atm/K mol)(295 K) n = 0.00259 mol 0.103 g/0.00259 mol = 39.8 g/mol
200
Based on its name, which carbon compound contains the fewest carbon atoms? ethanol, methane, chlorobutane, or propyl alcohol
methane (1 C)
200
Which covalent bond is the most polar? H-H, H-O, H-N, or H-S
H-O
200
In hydrogen iodide _______________ are the most important intermolecular forces.
dipole-dipole forces
300
Propane is used as fuel in backyard grills. How many grams of carbon dioxide are produced from burning 500.0 grams of propane?
1648 g CO2 44.01g CO2 . 6 mol CO2 . 1 mol C6H8 . 500.0g C6H8 = 1648g CO2 1 mol CO2 1 mol C6H8 80.12g C6H8
300
Which aqueous solution has a boiling point closer to its predicted value, 0.01 molal NaBr or 0.01 molal MgCl2?
0.01 molal NaBr
300
Predict the geometry of nitrous oxide, N2O (atomic order N-N-O).
linear :N---N-O:::
300
Mixing which of the following will produce a precipitation reaction? a) HNO3 + Sr(OH)2 b) LiNO3 and NaI c) Na2SO4 + Ba(OH)2 d) KOH + NaBr
c) Na2SO4 + Ba(OH)2 (from NaOH(aq) and BaSO4(s))
300
Which of the following isotopes is most likely to be unstable? H-1, B-11, O-16, Rb-72, or Ne-20
Rb-72
400
A reaction vessel contains 10.0 g CO and 10.0 g O2 which combine to form CO2. How many grams of CO2 can be produced?
15.7 g 44.01 g . 2 mol CO2 . 1 mol CO . 10.0g CO = 15.7 g 1 mol CO2 2 mol CO 28.01 g CO 44.01 g . 2 mol CO2 . 1 mol O2 . 10.0g O2 = 27.5 g 1 mol CO2 1 mol O2 32.00g CO
400
The label on a bottle of liquid fertilizer concentrate states that it contains 8 grams of phosphate per 100.0 mL and that 16 fluid ounces should be diluted with water to make 32 gallons of fertilizer to be applied to growing plants. What is the phosphate concentration in grams per liter in the diluted fertilizer? (1 gallon = 128 fluid ounces)
0.3 g/L (128 oz/1 gal) x 32 gal = 4096 oz 16 oz concentrate (@ 8g/100.0 mL) --> 32 gal dilute (8g/0.1000L)(16oz)=(X g/L)(4096 oz)
400
Calculate the mass of 2.50 x 10^4 molecules of nitrogen gas.
1.16x10^-18 g N2 28.02gN2 . 1molN2 . 2.50x10^4molec = 1.16x10^-18gN2 1 mol N2 6.022x10^23
400
Which compound has an incorrect formula? a) MgPO4 b) (NH4)2S c) Mg(HSO3)2 d) NaClO4
a) MgPO4 (should be Mg3(PO4)2)
400
Which electrode increases in mass during cell operation?
cathode
500
How many milliliters of 0.100 M NaOH are required to neutralize 50.0 mL of 0.215 M H2SO4?
215 mL 1000 mL NaOH . 2 mol NaOH . 0.215 mol H2SO4 . 50.0 mL = 215 mL 0.100 mol NaOH 1 mol H2SO4 1000 mL
500
Does the strength of an ion-ion attraction depend on the number of ions in the compound?
No, it depends on the charges and to some extent the size of the atoms.
500
Calculate the mass percent of chlorine in CCl3F (Freon-11).
77.42% [3 x 35.45] = 0.7742 [12.01+(3x35.45)+19.00]
500
A wether balloon was initially at a pressure of 0.950 atm, and its volume was 35.0 L. the pressure decreased to 0.750 atm, without loss of gas or change in temperature. What was the change in volume?
increase of 9.3 L (0.959 atm)(35.0 L) = (0.750 atm)(V) (1 mol)(273 k) (1 mol)(273 k) V = 44.3 L; 44.3 L-35.0 L = 9.3 L
500
When In-108 decays and forms Cd-108, what particle or type of radiation needs to be included on the right-hand side?
positron (1, ^0, B) (In-108 --> Cd-108)