AP Chem Unit 1 - 4 test questions
Based on the concepts of polarity and hydrogen bonding, which of the following sequences correctly list the compounds above in order of increasing solubility in water?
x<y<z
A precipitation formed
Ca + SO4 → CaSO4
On the Basis of the information above, which of the following arranges the binary compounds in order of increasing bond polarity
Ch4<SiCl4<SF4
The exothermic process above is best clarified as a
Chemical change because covalent bonds are broken and new covenant bonds are formed
For the dissolution of HCl in water represented above, which of the following pair included a Bronsted - Lowry base
H2O and Cl-
The electron - dot structure (lewis structure) for which of the following molecules would have two unshared pairs of electrons on the central atoms?
H2S
According to the VESPR model, the progressive decrease in the bond angles in the series of molecules CH4, NH4, and H2O is bet accounted for by the
Increasing number of unshared pairs of electrons
Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound.
It contains ionic compounds
Which of the following molecules has an angular (bent) geometry that is commonly represented as a resonance hybrid of two or more electron dot structures?
O3
The mass spectrum of element X is present in the diagram above. Based on the spectrum, which of the following can be concluded about the element X?
The atomic mass of x is between 90 and 92
Which of the following can be inferred from the diagram above that shows the dependence of potential energy on the internuclear distance between two atoms
The atoms form a bond with a bond length of 75 pm
The potential energy of a system of two atoms as a function of their internuclear distance is shown in the diagram above. Which of the following is true regarding the forces between the atoms when their internuclear distance is x?
The attractive and repulsive forces are balanced, so the atoms will maintain an average internuclear distance x
Which of the following is the conjugate acid to NH2
NH3
The reaction between a Bronsted Lowery acid and base
C2H3O2 + H3O → HCH2H3O2 + H2O
A 360. Mg sample of aspirin, C9H8O4 ( molar mass 180. g) is dissolved in enough water to produce 200. mL of a soultion. What is the molarity of aspirin in a 50. mL sample of this solution
0.0100M
If 50.0 ml of 1.0 M NaOH is diluted with distilled water to a volume of 2.0 L, the concentration of the resulting solution is
0.025M
Solid Al(No3)3 is added to distilled water to produce a solution in which the concentration of nitrate, [NO3-], is 0.10M. What is the concentration of aluminum ion, [Al^3+], in this solution?
0.033M
In 1.00 mol of potassium zirconium sulfate trihydrate, K4ZR(S04)4 x 3 h20 there are
4 x 6.02 ^23 potassium atoms
An Experiment was performed to investigate the reaction between metal and at different concentrations. Because the ion is green, the extent of the reaction was determined using spectrophotometric analysis. Four standard solutions were prepared by dissolving molar mass in water. The absorbance of each solution was measured; the results are shown in the table below and in the following plot of the absorbance date.
0.080 M
If 0.40 mol of H2 and 0.15 mol of O2 were to react as completely as possible to produce H2O, what mass of reactant would remain
0.20 g H2
What is the maxim number of moles of Al2O3 that can be produced by the reaction of 0.40 mol of Al with 0.40 mole of O2
0.20 mol
What number of moles of O2 is needed to produce 14.2 grams of P4O10 from P? (Molecular weight P4O10 = 284)
0.250
A 1.0L sample of an aqueous solution contains 0.10 mol of NaCl and 0.10 mol of CaCl2. What is the minimum number of moles of AgNO3 that must be added to the solution in order to precipitate all of the Cl- and AgCl (s)? (Assume that AgCl is insoluble)
0.30 mol
A solution of methanol, CH3OH, in water is prepared by mixing together 128g and 108g of water. The mole fraction of methanol is the solution is closest to
0.40
A 0.20 mol sample of MgCl and a 0.10 mol sample of KCL are dissolved in water and diluted to 500 ML. What is the concentration of Cl in the Solution?
1.0
A student prepares a solution by dissolving 60.00 g of glucose (molar mass 180.2 g mol ^ -1) in enough distilled water to make 250.0 ml of a solution. The molarity of the solution should be reported as
1.332
How many mL of 10.0 M HCl are needed to prepare 500. mL of 2.00 M HCl?
100. mL
When the equation is balanced above and all the coefficients are reduced to their lowest whole number terms, the coefficient for O2 is
12
A lewis diagram for the molecule is shown. In the actual molecule the bond angles are closet to
120 degrees
Which of the following represents the ground state electron configuration for the mn^3+ ion? ( Atomic number Mn = 25)
1s2 2s2 2p6 3s2 3p6 3d4
Based on the half reactions, what is the coefficient for Al if the equation for oxidation- reduction reaction is balanced with the smallest whole number coefficients
2
The reaction in which single species is both oxidized and reduced
2 H2O →O2 + 2H2O
An oxidation reduction reaction that is also a synthesis reaction
2 Mg + O2 → 2MgO
A sealed vessel contains 0.200 mol of Oxygen gas, 0.100 mole 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
2.00 atm
In the reaction represented above, what is the total number of reactants consumed when 1.00 mole of CO2 is produced
2.00 mol
Which of the following changes in volume will double the amount of Mg(OH)2 produced
20. Mol
A reaction in which the same reactant undergoes both oxidation and reduction
3Br + 6OH → 5Br - + 3BrO3 + 3 H2O
When the equation is balanced above and all the coefficients are reduced to their lowest whole number terms, the coefficient for H3PO4 (l)
4
If the absorbance of the mixture is 0.20 at 453 atm, how many moles of Fe 3+ were present in the 100. mL sample?
4x10 ^-6 mol
A sample of CaO (molar mass 1.00g) was reported as being 30. Percent Ca. Assuming no Calcium was present in any impurities, the percent of CaCO3 in the sample is
75%
For one of the prodecues, the student concluded that a physical change took place, but not a chemical change. Which of the following could have been the results of the procedure
A cube of metal was changed into a flat sheet of metal
The first five ionization energies of an unknown element are listed in the table above. Which of the following statements correctly identifies the element and cites the evidence supporting the identification?
Al, because of the large difference between the third and fourth ionization energies
Which has a central atom with less than an octet of electrons
BH3
Atoms of Mg combine with atoms of F to form a compound. Atoms of which of the following elements combine with atoms of F in the same ratio
Ba
Which of the molecules represented below contains carbon with sp^2 hybridizations?
C2H2Cl2
Has the highest ionization electronegativity
Br
If Na reacts with Cl to form NaCl, which of the following elements reacts with Na to form an Ionic compound in a one to one ratio, and why?
Br, because it has the same number of valence electrons as Cl
The table above shows the structural formulas and molar masses for three different compounds in order of increasing boiling points?
Butane<acetone< 1- Propanol
Which molecule has only one double bond
C2H4
Which of the following molecules contains only single bonds?
C2H6
A 23.0g sample of a compound contains 12.0g of C, 3.0g of H and 8.0g of O. Which of the following is the empirical formula of the compound
C2H6O
The molecular formula and molar mass of two straight - chain hydrocarbons as listed in the table. Based on the information in the table, which compound has the higher boiling point, and why is that compound's boiling point higher?
C4H10, because it has more electrons, resulting in greater polarizability and stronger dispersion forces
Sodium chloride is least soluble in which of the following liquids?
CCl4
In which of the following liquids do the intermolecular forces include dipole-dipole forces
CH2F2 (l)
The four species above have the same electron configuration, 1s2 2s2 2p6 3s2 3p6. Which of the following statements correctly identifies the species with the largest radius and provides an explanation based on coulomb's law?
Cl-, because its nuclear charge exerts the least attractive force on the electrons in the 3p sublevel
Which of the following lists Mg, P, and Cl in order of increasing atomic radius?
Cl<P<Mg
In which of the following compounds is the mass ratio of chromium to oxygen closet to 1.62 to 1.00?
CrO2
Has the largest atomic radius
Cs
Has the lowest ionization energy
Cs
RbCl has a high boiling point. Which of the following compounds is also likely to have a high boiling point, and why?
CsCl, because its elements have a very different electronegative and it is an ionic compound
To make Au stronger and harder, it is often alloyed with other metals, such as Cu and Ag. Consider two alloys, one of Au and Cu and one of Au and Ag, each with the same mole fraction of Au. If the Au/Cu alloy is harder than the Au/Ag alloy, then which of the following is the best explanation based on the information in the table?
Cu atoms are smaller than Ag atoms, thus they interfere more with the displacement of atoms in the alloy
A student performed a fractional distillation of a mixture of two straight - chain hydrocarbons, and using four clean, dry flasks, the student collected the distillate over the volume ranger ( A,B,C,D) shown in the graph above. Over what volume range should the student collect the distillate of the compound with the stronger intermolecular forces?
D
A mixture containing equal number of moles of ethyl acetate and butyl acetate was separated using distillation. Based on the diagrams shown above, which of the following identifies the substance that would be initially higher concentration in the distillate and correctly explains why that occurs
Ethyl acetate, because it has shorter carbon chain and weaker london dispersion forces
Which of the following substances F2, HCl, and HF are in order of increasing boiling point?
F2<HCl<HF
Which of the following is the net ionic equation for the reaction between aqueous sodium fluoride and hydrochloric acid
F^- (aq) + H^+ → HF(aq)
At 298 K and 1 atm, Br2 is a liquid with a high vapor pressure, and Cl2 is a gas. Those observations provide evidence that under the given conditions, the
Forces among Br2 molecules are stronger than those among Cl2 molecules
Consider atoms of the following elements. Assume that the atoms are in the ground state. The atom that contains only one electron in the highest occupied energy sublevel.
Ga
Which has two lone pairs of electrons?
H2O
All the reactions represented above occur in an aqueous solution of oxalic acid. Which of the following represent a BL conjugate acid- based pair.
HC2O4 and C2O2-4
Which substance listed above ( Ne,HF, C2H6, CH4) has the highest boiling point and why?
HF, because its molecules can form hydrogen bonds
The London dispersion forces are weakest for which of the following gasses under the same conditions of temperature and pressure?
H^2
The Photoelectron spectra for H and He are represented above. Which of the following statements best accounts for the fact that the peak on the He spectrum is farther to the left and higher than the peak on the H spectrum
He has a greater nuclear charge than H and an Additional electron in the same energy level
When hafnium is heated in an atmosphere of chlorine gas, the produce of the reaction is found to contain 62.2 percent Hf by mass and 34.7 percent Cl by mass. What is the empirical formula for this compound
HfCl3
Which of the following represents a pair of isotopes? Atomic Number | Mass Number
I. 6|13 ll. 7|14
Which of the following is true about the reaction
It is a redox reaction, because Cu is oxidized and the nitrogen atom in NO3- is reduced
A compound contains 1.10 mol of K, 0.55 mol Te, and 1.65 mol O. What is the simplest formula of this compound?
K2TeO3
On the basis of the solubility curves shown above the greatest percentage of which compound can be recovered by cooling a saturated solution of that compound from 90 degrees celsius to 30 degrees celsius
KNO3
1s^2 2s^2 2p^6 3s^2 3p^6 Which of the following has the electron configuration above
K^+
The Lewis structure for ___ is shown. Which of the following is the predominant type of intermolecular force among molecules?
London Dispersion Forces
According to the information in the table above a 1.00g sample of which of the following contain the greatest mass of oxygen
MgO
The lattice energy of a salt is related to the energy required to separate the ions. For which of the following pairs of ions is the energy that is required to separate the ions largest? ( Assume that the distance between the ions in each pair is equal to the sum of the ionic radii)
Mg^2+ (g) and O^2- (g)
Which statement correctly compares what occurs when molecules absorb photons in the microwave region with what occurs when molecules absorb photons in the infrared regions
Microwave photons cause the molecule to increase their rotational energy states, whereas infrared photons cause the molecules to increase their vibrational energy states
Which of the following molecules has the shortest bond length
N2
Which molecule has a pyramidal shape?
NH3
According to the complete photoelectron spectrum which of the following is the identity of the element
Ne
Which of the following represents a process in which a species is reduced
No3- → NO
Which has a bond order of 2
O2
Resonance is the most commonly used to describe the bonding in molecules of which of the following?
O3
Based of the balanced chemical equation, which of the following identifies the oxidation and reduction half reactions
Oxidation - Cu→ Cu ^2+ + 2e- Reduction - Ag^+ + e- → Ag
Which molecule has a trigonal pyramidal geometry
PH3
A precipitation reaction
Pb + CrO4 → PbCrO4
Based on the information in the table below, which of the compounds has the highest boiling point and why?
Propanic acid, because it can form intermolecular hydrogen bonds
How many protons, neutrons, and electrons are in an 56/26 Fe atom
Protons - 26 Neutrons - 30 Electrons - 26
Which is a polar molecule?
SO2
In which of the following species does sulfur have the same oxidation number as it does in H2SO4
SO2Cl2
In the reaction represented above, which of the following sets correctly identifies the hybridization of the atoms before and after the reactions occurs
Set B
The reaction between aqueous (SrCl2) and aquoes (K2SO4) forms a precipitate of (SrSO4). Which of the following represents the net ionic equation for the reaction?
Sr + SO4 → SrSO4
Which of the following ions has the same number of electrons as Br -
Sr^2+
A 2 mol sample of F2 reacts with exces NaOH according to the equation above. If the reaction is repeated with excess NaOH but with 1 mol of F2 which of the following is correct
The amount of OF2 produced is halved
The element C and Se have the same electronegativity value, 2.55. Which of the following claims about the compound that forms from C and Se is most likely to be true
The carbon to selenium bond is nonpolar covalent
The table shows the melting point of MgO (s) and NaF(s). Which of the following best helps explain why the melting point of MgO(s) is much higher that that of NaF.
The charges of Mg^2+ and O^2- ions are greater than those of Na^+ and F^- ions
Which of the following statements related to the experiment ( mass of crucible after heating) is correct
The mass of the sample increased, so chemical change occurred when bonds formed between the metal and another substance
A sample of __ is placed in a rigid vessel with a moveable piston. The volume of the gas is reduced by moving the piston downward while the temperature is maintained at__, as shown above. The pressure of the gas versus the volume is plotted in the graph below,
The molecules strike the walls of the vessel more frequently
An ionic crystal is added to water and starts to dissolve as shown in the particulate representation. Based on the orientation of the water molecules, what can be assumed about the charge of the hydrated particle indicated by the arrow?
The particle is positively charged, because the oxygen atoms in water are attracted to it
A sample of a solid labeled as NaCl may be impure. A student analyzes the sample and determines that it contains 75% chlorine by mass. Pure NaCl contains 61% chlorine by mass. Which of the following statements is consistent with the data
The sample contains NaCl and LiCl
The table above shows the first ionization energy and atomic radius of several elements. Which of the following best helps to explain the deviation of the first ionization energy of oxygen from the overall trend
There is repulsion between paired electron in oxygen's 2p orbitals
The surface of the paper is moderately polar. What can be concluded about x and Y based on the experimental results
Y is more polar than X
When reaction 3 occurs, does the hybridization of the carbon atoms change?
Yes , it changes from Sp to Sp^2
The hybridization of the carbon atoms in molecule represented can be described as
sp^3
The potential energy as a function of internuclear distance for three diatomic molecules, X2, Y2, and Z2, is shown in the graph above. Based on the data in the graph, which of the following correctly identifies the diatomic molecules, x2,y2, and z2?
x2 y2 z2 h2 n2 o2
