Analyze Models
Write the ground-state electron configuration for the Na+ ion
1s22s22p6
Testing the electrical conductivity of an aqueous solution of the substance
Which of the following contains only single bonds?
CH3COOH, C2H6, C6H6, HCN
C2H6
4 FeS(s) + 7 O2(g) --> 2 Fe2O3(s) + 4 SO2(g)
Due to the presence of FeS(s) as an impurity, the combustion of some types of coal results in the formation of SO2(g), as represented by the equation above. Also, SO2(g) can react with O3(g) to form SO3(g), as represented by the equation below.
SO2(g) + O3(g) <--> SO3(g) + O2(g)
Determine the limiting reactant and calculate the theoretical yield of SO2 when 2.0 mol of FeS(s) reacts with 4.0 mol of O2(g).
Limiting Reactant: FeS(s)
Theoretical Yield: 2.0 mol SO2(g)
Which of the following molecules is nonpolar but has polar covalent bonds?
H2O2, H2O, CCl4, CH2Cl2
CCl4
3Does the hybridization of the carbon atoms change in the below reaction:
C2H2(g) + Cl2(g) --> C2H2Cl2(g)
Give the hybridization(s) of the carbon atoms.
Yes!
it changes from sp to sp3
A kinetics experiment is set up to collect the gas that is generated when a sample of chalk, consisting primarily of solid CaCO3, is added to a solution of ethanoic acid, CH3COOH. The rate of CaCO3 and CH3COOH is determined by measuring the volume of gas generated at 25 degrees celcius and 1 atm as function of time.
What is one change that you could make to increase the rate of gas production?
decrease particle size of CaCO3
increase the temperature
increase the concentration of acid
Draw a particle digram of AgNO3 dissolved in water.
Oxygen side of water pointed toward Ag+
Hydrogen side of water pointed toward NO3-
The rate law for the reaction of nitrogen dioxide and chlorine is found to be rate = k[NO2]2[Cl2]. By what factor does the rate of the reaction change when the concentration of both NO2 and Cl2 are doubled?
8
The mass percent of carbon in pure glucose, C6H12O6, is 40.0%. A chemist analyzing an impure sample of glucose determines that the mass percent of carbon is 38.2%. Which of the following impurities could account for the low mass percent of carbon in the sample?
H2O, C5H10O5, C6H12O6, C12H22O12
H2O
The structure benzene, C6H6, is shown in Figure 1. Considering the observation that benzene is only sparingly soluble in water, what intermolecular force(s) is(are) most likely occurring between water and benzene?
London Dispersion Forces
To determine the concentration of a NaOh solution, a student titrated a 50. mL sample with 0.10 M HCl(aq). The reaction is represented by the equation above. The titration is monitored using a pH meter, and the experimental results are plotted in the the graph in Figure 2.
One student titrated the NaOH(aq) with 1.0M HCl instead of 0.10M HCl. How would the student's titration curve differ from the original curve?
ending pH would be lower
equivalence point would occur at a lower volume of HCl added
Thymine and adenine form a base pair in the DNA molecule. These two bases can form a connection between two strands of DNA via two hydrogen bonds. Which of the diagrams in Figure 7 shows the correct representation of the hydrogen bonding (denoted by dashed lines) between thymine and adenine base pairs?
Choice D
A sealed vessel contains 0.200 mol of oxygen gas, 0.100 mol of nitrogen gas, and 0.200 mol of argon gas. The total pressure of the gas mixture is 5.00 atm. The partial pressure of the argon is what?
2.00 atm
A 10.0 g sample of Pb(NO3)2(s) is dissolved in distilled water and an excess of 1.0 M HCl(aq) is added. The PbCl2(s) formed is filtered and placed in an oven to dry. The final mass of the precipitate is significant greater than predicted. What is one source of error that could account for the discrepancy?
The precipitate was not dried to a constant mass.
The single-step reaction represented below takes place in a sealed container.
NO2Cl(g) + Cl(g) --> NO2(g) + Cl2(g)
What is one reaction condition you could change that would reduce the value of k, the rate constant for the reaction?
decreasing the temperature
The spontaneous reaction that occurs when the cell in Figure 3 operates is 2 Ag+ + Cd(s) --> 2 Ag(s) + Cd2+
What would happen to the voltage if the silver electrode is made larger?
No change in voltage occurs
Equal volumes of solutions in two different vessels are represented in Figure 6. If the solution represented in vessel 1 is KCl, what could be the formula for the solution shown in vessel 2?
XY2
Gaseous hydrogen and gaseous chlorine can react to form hydrogen chloride gas, as represented by the following equation:
H2(g) + Cl2(g) --> 2 HCl(g)
Based on the table of bond energies in Figure 8, what is the value of ΔH for the reaction?
-183 kJ/mol
An acetate buffer solution is prepared by combining 50. mL of 0.20 M acetic acid, HC2H3O2(aq), and 50. mL of 0.20 M sodium acetate, NaC2H3O2(aq). A 5.0 mL sample of 0.10 M NaOH(aq) is added to the buffer solution. Which acetate species is present in greater concentration after the NaOH(aq) is added? (The pKa of acetic acid is 4.7.)
NaC2H3O2
Rank the four species present in an aqueous solution of the weak acid H2C2O4 from highest to lowest concentration at equilibrium.
H2C2O4 > H3O+ > HC2O4- > C2O42-
What should you do to prepare a buret before a titration?
Rinse the buret twice with some of the titrant solution
A particle view of H2O2(aq) is shown in Figure 4. The H2O2 is titrated ith KMnO4(aq), as represented by the equation below:
2 MnO4-(aq) + 5 H2O2(aq) + 6 H+(aq) --> Mn2+(aq) +5 O2(g) + 8 H2O(l)
Which particle diagram in Figure 5 best represents the mixture when the titration is halfway to the equivalence point? (H2O and H+ ions are not shown).
Choice C
The equilibrium constant for a reaction is greater than 1.0 at temperatures above 500 K but less than 1.0 at temperatures below 500 K. What can be concluded about the values of ΔH and ΔS for the reaction?
ΔH > 0
ΔS > 0
NO(g) + NO3(g) --> 2 NO2(g)
rate = k[NO][NO3]
The reaction represented above occurs in a single step that involves the collision between a particle of NO and a particle of NO3. A scientist correctly calculates the rate of collisions between NO and NO3 that have sufficient energy to overcome the activation energy. The observed reaction rate is only a small fraction of the calculated collision rate. What could explain the discrepancy besides a high activation energy?
The two reactant particles must collide with a particular orientation in order to react.