Atoms, Molecules, & Ions
Protons: 38
Neutrons: 52
Electrons: 38
What is the wavelength of light (in nm) produced by electronic transition between levels 4 and 2 of a hydrogen atom?
A. 182 nm
B. 364 nm
C. 486 nm
D. 1450 nm
C. 486 nm
Avogadro's number equals the number of:
A. atoms in one mole of O2
B. atoms in one mole of atoms
C. marbles in one mole of marbles
D. atoms in one mole of atoms and marbles in one mole of marbles
D. atoms in one mole of atoms and marbles in one mole of marbles
(The mole is not limited to quantifying the number of atoms)
The limiting reagent for a given reaction can be recognized because it is the reagent that:
A. has the smallest coefficient in the balanced equation for the reaction
B. has the smallest mass in the reaction mixture
C. is present in the smallest molar quantity
D. will be used up first
D. will be used up first
As water is being added to a concentrated NaOH solution:
A. the moles of solute are decreasing, and the molarity is decreasing
B. the moles of solute are decreasing, and the volume is increasing
C. the volume of the solution is increasing, and the molarity is decreasing
D. the volume of the solution is increasing and the molarity is increasing.
C. the volume of the solution is increasing, and the molarity is decreasing
The element thallium (Tl) has two stable isotopes, 203Tl and 205Tl. How would you describe the relative abundance of each of these isotopes?
The atomic mass of thallium is 204.4amu. Because the average mass is closer to 205 than 203, and weighted average is used to calculate atomic mass, the 205Tl isotope must be in higher abundance than the 203Tl isotope.
In the energy diagram, transitions between energy levels are denoted by arrows. Which transition corresponds to the absorption of the shortest wavelength of light?
E1 -> E3
What mass of carbon is present in 0.500 mol of sucrose (C12H22O11; molar mass = 342)?
A. 6.01g
B. 72.0g
C. 144. g
D. 228. g
B. 72.0 g
How many moles of Ba3N2 are necessary to react completely with 1.5 mol of water in the following reaction:
Ba3N2 + 6H2O -> 3Ba(OH)2 + 3NH3
A. 0.25 mol
B. 1 mol
C. 6 mol
D. 9 mol
A. 0.25 mol
What mass, in grams, of sodium ions are there in 25mL of 0.75 M Na2SO3??
Molar mass (g/mol)
Na+: 22.99
Na2SO3: 126.1
0.87g
Which of the following has twenty-six electrons?
A. Cr2+
B. Fe2+
C. Ni2+
D. Cu2+
C. Ni2+
Which atom has the largest atomic radius?
A. K
B. I
C. Rb
D. Sn
C. Rb
The number of atoms in 9.0g of aluminum is the same as the number of atoms in:
A. 8.1g Mg
B. 9.0g Mg
C. 12.1g Mg
D. 18.0g Mg
A. 8.1g Mg
What is the theoretical yield of aluminum chloride that could be obtained from 6.00 mol of barium chloride and excess aluminum sulfate?
Al2(SO4)3 + 3BaCl2 -> 3BaSO4 + 2AlCl3
Molar mass (g/mol):
AlCl3: 133.3
BaCl2: 208.23
Al2(SO4)3: 342.15
534g
For DOUBLE the points, what is the actual yield if the percent yield is 79.5%?
What is the molar concentration of a solution when 7.00mL of a 3.25M aqueous solution is diluted to 25.00mL?
A. 0.280M
B. 0.910M
C. 1.10M
D. 2.15M
B. 0.91M
List one alkali metal, one alkali earth metal, and one halogen.
Alkali metals: Li, Na, K, Rb, Cs, Fr
Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra
Halogens: F, Cl, Br, I, At, Ts
What is the energy of a photon with a wavelength of 656 nm?
A. 3.03x10-19 J
Which compound contains the largest percent by mass of oxygen?
A. CO2
B. NO2
C. SO2
C. SiO2
How many water molecules are produced if 0.34 mol of propane (C3H8) combusts in excess oxygen?
C3H8 + 5O2 -> 3CO2 + 4H2O
8.2x1023
What particles would be present in NH3 (aq)?
A. water molecules, NH4+ ions, and OH ions
B. water molecules, H3O+ ions, and NH2- ions
C. water molecules and NH3 molecules
D. water molecules, NH3 molecules, and a small number of NH4+ ions and OH- ions
D. water molecules, NH3 molecules, and a small number of NH4+ ions and OH- ions
What is the charge on ions of alkali earth metals?
+2
This diagram is an early model for the atom. This model differs from the current model because in the current model:
A. electrons do not move in orbits
B. energy levels are not quantized
C. electron orbits are ellipses, not circles
D. electrons exhibit only particle-like behavior
A. electrons do not move in orbits
What is the empirical formula of a compound of carbon, hydrogen, and oxygen that contains 51.56% carbon and 14.09% hydrogen by mass?
A. C7H10O
B. C8HO
C. C12H30
D. C8H13O2
B. C8HO
An initial reaction mixture of O2 and F2 is shown to the right. Which representation shows what would be present after the reaction is complete?
B
In which of the following reactions is carbon reduced?
A. CO + O2 -> CO2
B. CO2 + H2O -> H2CO3
C. CH4 + 2O2 -> CO2 + 2H2O
D. C2H2 + H2 -> C2H4
D. C2H2 + H2 -> C2H4