Chem Final Exam
A sample of methane gas, CH4(g), occupies a volume of 60.3L at a pressure of 469 torr and a temperature of 29.3 C. What would be its temperature at a pressure of 243 torr and volume of 60.3 L?
-116.5 C
What is the molarity of a solution made by dissolving 4.88 g of KCl in 423 mL of solution?
0.115 M KCl
As sample of nitrogen gas is confined to a 14.0 L container at 375 torr and 37 C. How many moles of nitrogen are in the container?
0.271 mol
How many gram of chromium are needed to make 2.20 x 10^5 g of a solution that is 1.70 ppm chromium by mass?
0.374 grams Cr
What is the concentration of a solution formed by diluting 25.0 mL of a 3.2 M NaCl solution to 135.0 mL?
0.59 M NaCl
Consider the neutralization reaction below. For titiration, how much of 1.20 M NaOH will be neede to neutralize 225 mL of 2.5 M H2SO4 acid? H2SO4(aq) + NaOH(aq) --> H2O(l) + Na2SO4(aq) [not balanced]
0.94 L
The [OH-] in a sample of egg whites is 6.3 x 10 ^-7M. What is the [H3O+] in these egg whites?
1.6 x 10^-8 M H3O+
If 145-mg of the cholesterol lowering drug Tricor is prescribed to a 185-lb patient, what dosage is the patient receiving in mg/kg of his body weight?
1.72 mg/kg
What is the boiling point of a solution prepared from 2.00 moles of KCl in 1.00 kg of water?
102.04 deg C
Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?
107 g
Magnesium reacts with iron (III) chloride to form magnesium chloride and iron. 3Mg(s) + 2FeCl3(s) --> 3MgCl2(s) + 2Fe(s) A mixture of 41.0 g of magnesium (mw=24.31 g/mol) and 175 g o iron (III) chloride (mw=162.2 g/mol) is allowed to react. What mass of magnesium chloride (mw= 95.21 g/mol) is formed?
154 g MgCL2
How many grams of glucose (C6H12O6, Molar Mass= 180 g/mol) are contained in 555 mL of a 1.77 glucose solution?
177 g C6H12O6
What is the molar mass of (NH4)3AsO4?
193.03 g/mol
What is the electron configuration of an F- ion?
1s^2 2s^2 2p^6
Consider the element selenium, [Ar]4s^2 3d^10 4p^4. How many electrons are unpaired?
2
Carry out the following calculation and report the answer using the proper number of significant figures: 38.251 x 73.1
2.80 x 10^3
If a tree is 89.5cm tall, what is the tree's height expressed in feet?
2.94 ft
The isotope with the symbol 37^ 17Cl______ has_____ neutrons, _____ electrons, ______ protons, respectively?
20 neutrons, 17 electrons, 17 protons
A solution is made by combing 569 mL of water and 238 mL ethanol and mixing throughly. What is the concentration of ethanol in units of volume/volume percent?
29.5% (v/v) ethanol
How many bonding pairs of electrons are present in the Lewis structure of ammonia, NH3?
3
In neutral molecules, how many bonds are commonly formed by nitrogen? And how man by oxygen?
3 and 2
Cacultate the pH of a buffer solution that contains 0.25 M benzonic acid (C6H5CO2H) and ).15M sodium benzoate (C6H5CooNa). [Ka= 6.5 x 10 ^-5 for benzoic acid]
3.97
A hiker with hypothermia has a body temperature of 82 F. What is his body temperature in Kelvin?
301 K
The symbol for the isotope with A=31 and Z=15 is ________ and has _________ number of unpaired electrons.
31 15 P, 3e-
The recommended dietary allowance for calcium for teenage children is 1,300 mg per day. If an 8.0-fl oz glass of reduced-fat milk contains 298 mg of calcium, how many fluid ounces of milk does a teenager need to drink to get the entire recommended amount of calcium from this milk?
35 fl oz
Consider the reaction: 2NO(g) --> N2(g) + O2(g) <--- If [N2]= 0.520, [O2]= 0.0662 M, and [NO]= 0.00956 at equilibrium, what is the value of K?
377
Aluminum will react with bromine to form aluminum bromide. Al(s) + Br2(l) --> Al2Br6(s) [unbalanced] How many moles of Al are needed to form 2.43 mol of Al2Br6?
4.86 mol
Calculate the mass in grams of 8.35 X 10^22 of CBr4.
46.0 g
How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH3? 4NH3(g) + 5O2(g) --> 4NO(g) + 6H2O(g)
469.7 g
The estimated average daily requirement of folic acid for pregnant females is 520 micrograms. What is the accurately expressed value?
520 ug
What is the percent yeild for the reaction PCl3(g) + Cl2(g) --> PCl5(g) if 119.3 g of PCl5 (mw= 208.2 g/mol) are formed when 61.3 g of Cl2 (mw= 70.91 g/mol) react with excess PCl3?
66.3%
The pH of a lime is 1.90. What is the [OH-]?
7.9 x 10^-13 M OH-
What is the expression for the equilibrium constant for the reaction: 2 C2H6(g) + 7 O2 (g) --> 4CO2(g) + 6H2O(g)? <--
K= [CO2]^4 [H2O]^6 __________________________ [C2H6]^2 [O2]^7
Octane, C8H18, has the structure shown below. What is the strongest type of intermolecular force that exist between two octane molecules. H H H H H H H H 1 1 1 1 1 1 1 1 H-C-C-C-C-C-C-C-C-H 1 1 1 1 1 1 1 1 H H H H H H H H
London dispersion forces
The electronic structure 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8 refers to the ground state of
Ni
From the atoms listed Ga, K, Rb, Br; _______ has the largest atomic radius and the atom _______ smallest ionisation energy
Rb, Rb
What is the chemical formula for tin(IV) hydroxide?
Sn(OH)4
Which number is the smallest? a) 5.73 x 10^-3 b) 5.73 x 10^2 c) 573 d) 5.73 x 10^3 e) 5.73 x 10^-2
a) 5.73 x 10^-3
Which chemical formula is correct? a) Mg(OH)2 b) K2CN c) Ag(CH3CO2)2 d) SrCl e) more than one formula is correct
a) Mg(OH)2
Which of the following is a strong acid? a) H3PO4 b) HNO3 c) HF d) CH3COOH e) H20
HNO3
A sample of gas contains four gases with the following partial pressures: He (113 mm Hg), Ne (184 mm Hg), and Xe (445 mm Hg). What is the total pressure of the sampler?
777 mm Hg
A saline solution used in intravenous drips for patients who cannot take oral fluids contains 0.92% (w/v) NaCl in water. What volume of the saline solution must be administered to the patient in order to deliver 7.7g of NaCl?
840 mL of saline solution
How much energy is required to heat 800 grams of octane from 35.0 C to 85.0 C? {Note for OCTANE: Boiling point= 126 C, Melting Point= -57 C, Specific heat= 2.15 J/g C}
86.0 kJ
Which element may have less than eight valence electrons around it when present in a covalent compound?
B
Which of the following statements about molecular shape and molecular polarity is false? a) H2O is bent and polar b) HOF is bent and nonpolar c) CF4 is tetrahedral and nonpolar d) CH3F is tetrahedral and polar e) BH2F is trigonal planar and polar
B) HOF is bent and nonpolar
What is the formula for the ionic compound formed when Bromine and beryllium combine?
BeBr2
Considering the reaction below complete the statement: _______ is reduced and _________ is the reducing agent. 6H+(aq) + 2Al(s) ---> 2Al^3+ (aq) + 3H2(g)
H+, Al
Which of the following statements concerning a solution is false? a) a solution is a heterogenous mixture of two or more pure substances b) A solution has its components uniformly distributed c) a solution is likely to form when the solute(s) and the solvent have similar properties d) a solution is composed of a solvent and one or more solutes the solutes; the solute(s) dissolve in the solvent e) more than one is false
a) a solution is a heterogenous mixture of two or more pure substances
Which of the following energy quantities is equivalent to 258 Cal? a) 258 cal b) 1080 kJ c) 6.17 x 10^4 D) 1080 J E) None of the above
b) 1080 kJ
Which solution has the lowest boiling point? a) A solution formed by dissolving 0.75 mol Na3PO4 in 1.00 kg of water b) A solution formed by dissolving 0.75 mol of glucose (C6H12O6) in 1.00 kg of water c) A solution formed by dissolving 0.75 mols of KCL in 1.00 kg of water d) A solution formed by dissolving 0.75 mols of Ca(NO3)2 in 1.00 kg of water e) all of the solutions described have the same boiling point.
b) A solution formed by dissolving 0.75 mol of glucose (C6H12O6) in 1.00 kg of water
Which of the following combinations cannot function as a buffer solution? a) HCN and KCN b) HNO3 and NaNO3 c) HF and NaF d) HNO2 and NaNO2 e) all of the above combinations will function as a buffer solution
b) HNO3 and NaNO3
Which of the these salts will form a basic solution on dissolving in water? a) NaCl b) KCN c) NaNO3 d) NH4Br e) None of the above
b) KCN
The electron configuration of chlorine is 1s^2 2s^2 2p^6 3s^2 3p^5. Which statement about chlorine is correct? a) chlorine has 5 valence elctrons b) chlorine has 17 total electrons c) chlorine valence shell is the p shell d) chlorine has 5 electrons in the 3rd energy level e) none of the above
b) chlorine has 17 total electrons
Which is a molecular solid? a) MgCl2 b) sucrose (C12H22O11) c) Au d) SiO2 e) none of the above
b) sucrose (C12H22O11)
The reaction system is at equilibrium CS2(g) + 4H2(g) --> CH4(g) + 2H2S(g) <-- Which of the following statements describes the behaviour of the system if the concentration of hydrogen bonding? a) As equilibrium is reestablished, the concentration of carbon disulfide increases b) As equilibrium is reestablished, the concentration methane, CH4, decreases c) As equilibrium is reestablished, the concentration of hydrogen sulfide increases d) As equilibrium is reestablished, the concentration of hydrogen sulfide decreases e) As equilibrium is reestablished, all the concentration will decrease
c) As equilibrium is reestablished, the concentration of hydrogen sulfide increases
Which pair of the compounds will form a solution? a) NaCl and hexane (C6H14) b) H2O and CCl4 c) Benzene (C6H6) and hexane (C6H14) d) Na2SO4 and benzene (C6H6) e) none of the combinations above will form solutions
c) Benzene (C6H6) and hexane (C6H14)
Which of the following compunds has the highest boiling point? a) CH3CH2CH2Cl b) CH3CH2CH3 c) CH3CH2CH2OH d) CH3CH2CH2CH3 e) all have the same boiling point
c) CH3CH2CH2OH
Which of the following is NOT a conjugate acid-base pair? a) H3PO4 and H2PO4- b) H2PO4 and HPO4^2- c) H3PO4 and HPO4^2- d) HPO4^2- and PO4^3- e) H30+ and H20
c) H3PO4 and HPO4^2-
Which statement concerning the ion of Li+ is correct? a) Li+ has an octet of electrons in its valence shell b) Li+ is formed when a lithium atom gains one proton c) Li+ has two total electrons d) Li+ is formed when helium atom gains one electron e) none of the above
c) Li+ has two total electrons
Which of the following molecules is a covalent compound? a) Na2O b) CaCl2 c) NO2 d) CsCl e) none of the above
c) NO2
Which of the following statements is FALSE? a) changes in state such as melting and boiling are physical changes b) a compound can be broken down in to simpler substances c) dissolving sugar in water involves a chemical change d) elements and compounds are both classified as pure substances e) isotopes are atoms of the same elements having a different number of neutrons
c) dissolving sugar in water involves a chemical change
Considering the reaction: C3H8(g) + 5O2(g)--> 3CO2(g) + 4H2O (g), whereas ΔH= -531 kcal. Which statement concerning this reaction is true? a) The products are higher in energy than the reactants b) the reaction is endothermic c) the bonds formed in the products are stronger than the bonds broken in the reactants. d) Heat is absorbed e) all of the above is true
c) the bonds formed in the product are stronger than the bonds broken in the reactants.
Which statement is correct according to the modern description of the electronic structure of an atom? a) The mass of the atom subsides in the nucleus and electrons move freely in space b) the charge of the nucleus is negative and the energy of electrons is restricted to specific values c) the charge of the nucleus is positive and electrons occupy discrete energy levels d) the energy of electrons is quantised and their movement is random e) none of the above
c) the charge of the nucleus is positive and electrons occupy discrete energy levels
The density of human urine is normally between 1.003 and 1.030 g/mL, and is often used as a diagnostic tool. If a 25.00 mL sample of urine from a patient has a mass of 26.875 g, how does the density of the urine sample compare to the normal range? a) the density of the sample is within the normal range b) the density of the sample is lower than the normal range c) the density of the sample is greater than the normal range d) there is insufficient information to make a comparison
c) the density of the sample is greater than the normal range
Which if any, of the following properties applies to weak acid? a) they are strong electrolytes b) they are excellent conductors of electrictiy c) when dissolved in water, they don not ionize completely d) all of the above e) none of the above
c) when dissolved in water, they don not ionize completely
Which ionic compound is not soluble in water? a) LiOH b) Pb(CH3CO2)2 c) Ca(NO3)2 d) BaSO4 e) More than one of the ionic compounds is not soluble in water.
d) BaSO4
Which is not an ionic compound? A) KCl B) Ca(NO3)2 C) FeBr3 D) CBr4 E) None of the above
d) CBr4
Which atom is the most electronegativity? a) Rb b) P c) I d) Cl e) not enough information
d) Cl
Which is true? a) all solids are crystalline solids b) a collid is a heterogenous misture that contains large particles (<1um) suspended in a liquid. The particles will settle out on standing c) polypropylene, a typical plastic, is an example of an ionic solid d) melting is an endothermic process e) All of the above are true
d) melting is an endothermic process
What is the name of P2S5?
diphosphorus pentasulfide
A bronsted-Lowry acid
donates hydroxide ions when dissolved in water
What is the charge on the gold (Au) cation in the compound Au2O3?
e) +3
Which of the following bond are non-polar (electrons are equally shared)? a) C-O b) Si-F c) H-Br d) C-F e) C-I
e) C-I
Which cylinder at STP will contain the greatest number of gas particles? a) a 5.0-L cylinder of neon b) a 5.0-L cylinder of nitrogen c) a 5.0-L cylinder of hydrogen d) a 5.0-L cylinder of helium e) all cylinders contain the same number of gas particles
e) all cylinders contain the same number of gas particles
Which statement about buffers is FALSE? a) a buffer typically consist of a weak acid and its conjugate base (or the sale of its conjugate base) b) the pH changes very little when acid or base are added to a buffer solution c) The blood of humans is buffered and utilizes the carbonic acid/ bicarbonate equilibrium d) For a buffer to be effective, the amount of new acid or base added to the solution must be small compared to the amount of buffer present. e) all the statements are correct
e) all the statements are correct
Which element is chemically similar to chlorine? a) argon b) oxygen c) calcium d) sulfur e) bromine
e) bromine
Covalent bonds result from the __________ electrons between two atoms.
equal sharing of and unequal sharing of are both correct
What is another name for an unshared pair of electrons in a covalent compound?
non-bonded electron pair and lone pair of electrons
Nonpolar compounds are soluble in
nonpolar solvents
What is the name for the ionic compound K2SO4?
potassium sulfate
Consider an endothermic reaction at equilibrium, 3O2(g) ----> 2O3(g) ΔH=143 kJ/mol What effect does increasing the temperature have on the equilibrium?
shifts the reaction to the right and increasing [products]
Electronegativity is a measure of
the attraction by an atom for electrons in a chemical bond
An equilibrium constant with a value of 7.6 x 10^6 indicates that at equilibrium __________
the products are favored