Big Idea 1
A compound found to contain 56.5% carbon, 7.11% hydrogen, and 36.4% phosphorus.
Determine the empirical formula.
C4H6P
Which of the following compounds will have the highest lattice energy?
LiF, MgCl2, CaBr2, and C2H6
MgCl2. C2H6 isn't an ionic substance, so it doesn't have lattic energy. LiF is composed of ions with charges of +1 and -1, so it won't be as strong as those with charges of +2 and -1. MgCl2 is smaller than CaBr2, so it will have the greatest lattice engergy according to coulomb's law.
An ion containing only oxygen and chlorine is 31% oxygen by mass. What is the emperical formula?
ClO-
After 44 minutes, a sample of 4419K is found to have decayed to 25% of the original amount present. What is the half life of 4419K?
22 minutes
A 0.1 molar solution of which of the following acids will be the best conductor of electricity?
H2CO3, H2S, HF, or HNO3
HNO3
The best conductor of electricity will be the solution that contains the most charged particles. HNO3 is the only strong acid listed in the answer choices, so it is the only choice where the acid has dissociated completely in solution.
True or False
According to Coulomb's law, the greater the charge of the nucleus, the more energy an electron will have.
True
A liquid whose molecules are held together by only which of the following forces would be expected to have the lowest boiling point?
Ionic bonds, London dispersion forces, hydrogen bonds, or metallic bonds
A liquid with a low boiling point must be held together by weak intermolecular forces, and london dispersion is the weakest kind.
If solutions containing equal amounts of AgNO3 and KCl are mixed, what is the identity of the spectator ions?
K and NO3-
When those solutions mix, a precipitate of AgCl will form, removing those ions from the solution. The remaining ions (K+ and NO3-) do not react and remain the same as they were when they started.
What two factors affect rate?
Concentration and Temperature
If the solubility of BaF2 is the equal to x, which of the following expressions is equal to the solubility product, Ksp, for BaF2?
x2, 2x2, 2x3, or 4x3
4x3
Determine the electron configuration for nickel.
1s22s22p63s23p63d84s2
A mixture of gases contains 1.5 moles of oxygen, 3.0 moles of nitrogen, and 0.5 moles of water vapor. If the total pressure is 700 mmHg, what is that partial pressure of the nitrogen gas?
According to Dalton's law, the total number of moles present is 1.5 + 3.0+0.5 = 5.0 total moles If there are 3 moles of nitrogen, then 3/5 of the pressure must be due to nitrogen.
(3/5)(700 mmHg) = 420 mmHg
If equimolar solutions of Pb(NO3)2 and NaCl are mixed, which ion will not be present in significant amounts in the resulting solution after equilibrium is established?
Cl-
The precipitate would be PbCl2, which would require twice as many Cl ions than Pb ions. If equal moles of both are used, the NaCl would be the limiting reactant, and almost all of the Cl ions would be present in the solid, with very few left in the solution.
When calcium chloride (CaCl2) dissolves in water, the temperature of the water increases dramatically. During this reaction, heat transfers from.....
The system to the surroundings
The reactions must be exothermic because the water heats up. In an exothermic reaction, heat is transferred from the system (the reaction itself) to the surroundings (the water).
The solubility of PbS in water is 3 x 10-14 molar. What is the solubility product constant, Ksp, for PbS?
9 x 10-28
Which of the following elements (Titanium, Manganese, Nickel, or Zinc) would have the most unpaired electrons?
Manganese
In all of these transition metals, the 3d subshell is the last one to receive electrons (Aufbau's Principle). The electrons will enter one by one into each orbital before any pair up (Hund's Rule) meaning manganese will have all five of its 3d electrons.
CO2, SO3, O2, and He
CO2
Use stoichiomety to find the unknown moles of the gas, and then use MM= g/mol to find the unknown molar mass of the gas.
If solutions of iron (III) nitrate and sodium carbonate are mixed, what would be the formula of the precipitate?
Fe2(CO3)3
Carbonates are insoluble when paired with iron. Iron has a charge of +3 and carbonate has a charge of -2. To cancel out, both charges need to have a magnitude of 6, requiring two iron atoms and three carbonate ions.
When CaCl2 dissolves in water, the temperature of the water increases dramatically. Which is the primary driving factor behind this reaction?
Entropy, Enthalpy, Both Enthalphy and Entropy, or Neither Enthalpy or Entropy
Both Enthalpy and Entropy
The reaction is exothermic, meaning it has a negative delta H, which means it's favored in terms of enthalpy. It is also favored in terms of entropy, as the ions start organized into the ionic lattice, and end up in a more disordered state.
What is the volume of 0.05M HCl that is required to neutralize 50mL of 0.10M Sr(OH)2 solution?
200 mL
Which element will have a higher electronegativity value: chlorine or bromine? Why?
Chlorine, because it's smaller
The smaller an atom is, the more the "pull" of the nucleus can be felt and the easier it will be for that element to attract more electrons.
How many moles of Na2SO4 must be added to 500 millimeters of water to create a solution that has a 2 molar concentration of the Na+ ion?
Moles= (molarity)(volume) Moles of Na+= (2M)(0.5L)= 1 mol
Because we get 2 moles of Na+ ions for every mole of Na2SO4 we add, so we need to add only 0.5 moles of Na2SO4.
Which of the following compounds is the oxidation number of chromium the greatest?
CrO4-2, CrO, Cr+3, Cr(s)
CrO4-2
H2O(l)-->H2O(s)
Which of the following is true for the above reaction?The value for delta S is positive, the value for delta G is zero, the value of delta H is negative, or the reaction is favored at 1.0atm and 298K
During a phase change, the products and reactants are at equilibrium with each other, meaning delat G is zero.
Which of the following species is amphoteric?
H+, CO3-2, HCO3-, or H2CO3
HCO3-