Exam 1
Chemistry for Engineers Exam-2 Notes
Exam Details
Name: Chemistry For Engineers 1450
Exam Points: 100
Date: 10/21/24
Duration: 1 hour 15 minutes
Questions Overview
Multiple Choice Questions
Element in Third Period, Group 5A (15)
a. Ge
b. Si
c. Al
d. Sc
e. P
True Statements
a. If a substance is soluble, it must be an electrolyte.
b. If a substance is an electrolyte, it must be soluble.
c. Weak electrolytes must be less soluble than strong electrolytes.
d. Nonelectrolytes are nonsoluble.
Molarity of HCl Solution
Calculate molarity from 1.56 g of gaseous HCl in 26.8 mL of solution
a. 0.63 M
b. 0.0043 M
c. 1.60 M
d. 4.31 M
Dilution of NaCl Solution
Initial: 500 mL of 1.0-M NaCl diluted to 750 mL.
What happens to moles of NaCl?
a. Decreases
b. Increases
c. Stays the same
d. Not enough information
Quantum Numbers for 4d Orbital
Acceptable set:
A) 4 2 3 -1/2
B) 4 2 0 +1/2
C) 4 3 -1 -1/2
D) 4 4 1 +1/2
a. A
b. B
c. C
d. D
Nuclide from Alpha Emission
What is formed when Th-230 undergoes alpha emission?
a. Au-226
b. Pa-230
c. Ra-230
d. Ra-226
Gas Density Comparison
At 25 °C and 1 atm:
a. NH3 (MM 17.4 g/mol)
b. Ar (MM 39.95 g/mol)
c. CO2 (MM 44.01 g/mol)
d. NO2 (MM 46.01 g/mol)
Diamagnetic Atom Identification
a. Cr 2+
b. Cl
c. O
d. Sr
Energy and Quantum Mechanics
Electron Transition Energy Release
Electron transitions in a hydrogen atom:
I. n = 2 → n = 1
II. n = 3 → n = 1
III. n = 1 → n = 4
Which releases the most energy?
a. I
b. II
c. III
d. Both I and II
Atomic Orbital Definition
In quantum mechanics, an atomic orbital:
a. Provides the position of an electron at any instant.
b. Locates all electrons in an atom.
c. Identical to Bohr's orbits.
d. Provides probability of electron location.
Highest Energy Quantum Numbers
Which set of quantum numbers represents the highest energy?
a. n = 3, l = 2, ml = -2, ms= +1/2
b. n = 2, l = 1, ml = 0, ms= -1/2
c. n = 4, l = 0, ml = 0, ms= +1/2
d. n = 3, l = 1, ml = 0, ms= +1/2
Isoelectronic Pair
Which forms an isoelectronic pair?
a. Ca2+ and Fe3+
b. Cl– and Ca2+
c. O2– and F
d. F and Cl–
Largest Ion Radius
Which ion has the largest radius?
a. K+
b. P3–
c. S2–
d. Cl–
Ionization Energies Period 3 Element
Name the period 3 element with the following ionization energies in kJ/mol:
IE1 730, IE2 1450, IE3 7700, IE4 10000
a. Al
b. Mg
c. P
d. S
Photon Energy Comparison
A green light photon has a _________ wavelength and energy than an infrared photon.
a. Longer, higher
b. Longer, lower
c. Shorter, lower
d. Shorter, higher
Thermodynamics & Kinetics
Wavelength Energy Comparison
Highest energy:
a. 450 nm
b. 225 nm
c. 3.50 x 10^-9 m
d. 8.40 x 10^-7 m
Cooling Rate of Objects
Which object cools the slowest?
a. Aluminum pan
b. Container of water
c. Copper pot
d. Iron skillet
Calculating Specific Heat
Formula: Specific heat = Q/(m * ΔT).
Given: 15.4 g metal, temperature rise = 6.75°C, energy = 40.0 J.
a. 0.385 J g−1 °C−1
b. 0.232 J g−1 °C−1
c. 0.902 J g−1 °C−1
d. 0.128 J g−1 °C−1
Precipitate with PO₄³⁻
Which forms a precipitate?
a. Na+
b. NH4+
c. Ca²⁺
d. None
Precipitate from Reaction
Precipitate from Fe(NO₃)₃ mixed with KOH.
a. KNO3
b. K(NO3)2
c. FeOH
d. Fe(OH)₃
Chemical Reactions and Energy Changes
Identifying Reducing Agent
In reaction: 3 Sn (NO₃)₂(aq) + 2 Fe(s) → 2 Fe(NO₃)₃(aq) + 3 Sn(s)
a. Sn
b. Fe
c. N
d. O
Oxidation Number of Sulfur
In S2O3²⁻, what is sulfur's oxidation number?
a. +8
b. +2
c. +5
d. +6
Heat Absorption in Chemical Reaction
For 0.771 mol of CF₄ from:
C (s) + 2 F₂ (g) → CF₄ (g), ∆H° = 141.3 kJ/mol
Calculate:
a. 183 J
b. 109 kJ
c. 183 kJ
d. 54.5 kJ
Enthalpy Sign for Water Phase Change
For H2O(s) → H2O(l), ∆H is:
a. Positive, endothermic
b. Negative, endothermic
c. Positive, exothermic
d. Negative, exothermic
Reaction Enthalpies and Generalizations
Enthalpy of Reaction Equals Enthalpy of Formation
Which reaction has this property?
a. KOH (s) → K+ (aq) + OH– (aq)
b. Ni (s) + ½ O₂ (g) → NiO (s)
c. 2 Fe (s) + 3 Cl2 (g) → FeCl3 (s)
d. AsF3 (s) → As (s) + 3/2 F2(g)
Breaking Bonds Energy Requirement
Reaction: 2 Cl(g) → Cl2(g)
a. Exothermic due to bond formation energy release.
b. Endothermic because bond breaking requires energy.
c. Endothermic due to forming bonds.
d. Exothermic due to breaking bonds.
Diluted HNO3 Solution
100.0 mL of 0.500 M diluted to 500.0 mL.
a. 0.0025 M
b. 0.1 M
c. 100 M
d. 2.5 M
Internal Energy Change Calculation
Absorbs 0.615 kJ heat and has 0.247 kJ work done on it.
a. 0.368 kJ
b. 0.862 kJ
c. 0.615 kJ
d. 0.431 kJ
Heat of Formation Calculation
Reaction: 2 PbS (s) + 3 O₂ (g) → 2 SO₂ (g) + 2 PbO (s), ∆H° = -828.4 kJ/mol
Determine heat of formation for PbS.
a. -200 kJ/mol
b. -100 kJ/mol
c. 611.1 kJ/mol
d. -159.2 kJ/mol
First Law of Thermodynamics
It states that:
a. Chemical reaction energy is constant.
b. Universe energy is always increasing.
c. Universe energy is constant.
d. Reactions always release energy.
Miscellaneous Problems
Molar Enthalpy for Given Reaction
Reactions provided with their respective enthalpy changes.
Determine enthalpy for:
4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g).
a. -3324.8 kJ/mol
b. 1089.9 kJ/mol
c. 13 kJ/mol
d. -906.3 kJ/mol
Pressure and Volume Relationship
For constant temperature, pressure increases to 3 times original, volume changes.
a. Decreases to 1/9
b. Increases to 9 times
c. Increases to 3 times
d. Decreases to 1/3
Ideal Conditions for Gas
Which conditions of P and T are most ideal?
a. High P, high T
b. High P, low T
c. Low P, low T
d. Low P, high T
Fastest Rate of Effusion
At the same temperature, which gas effuses the fastest?
a. HBr
b. O2
c. Cl2
d. CO
Gas Curve Identification
Which gas corresponds to curve III in a plot?
a. O2
b. N2
c. H2
d. F2
Heat of Combustion Reaction
Given reaction and ΔH, find heat of:
2 CO2(g) + H2O(g) → C2H2(g) + 5/2 O2(g).
a. -1300 kJ
b. 1300 kJ
c. 5200 kJ
d. none
Partial Pressure Calculation
Chamber with equal moles of gases and total pressure of 3.00 atm. Determine CO₂'s partial pressure.
a. 0.75 atm
b. 1.3 atm
c. 1.0 atm
d. Not enough information
Gas Laws and Equations
Gas Pressure Calculation
Calculate pressure of 1.2 mol methane in 3.3 L at 25 °C using R = 0.0821 L atm/mol K.
a. 8.13 atm
b. 0.75 atm
c. 8.892 atm
d. 4. 96.88 atm
Cobalt (III) Ion 3d Electrons
How many 3d electrons does Co3+ have?
a. 0
b. 7
c. 6
d. 5
Transition Metal Ion with No d Electrons
Identify the ion with no d electrons:
a. Ti+
b. Fe3+
c. Cr3+
d. Mn7+
Ground-State Chromium Electron Configuration
Which is correct for chromium?
a. 1s22s22p63s23p63d6
b. 1s22s22p63s23p64s23d4
c. 1s22s22p63s23p64s13d5
d. 1s22s22p63s23p64s24d5
Greatest Total Ion Concentration
Which solution has the greatest ion concentration?
a. 1 mole KCl in 1 L
b. 1 mole Fe(NO3)2 in 1 L
c. 1 mole KOH in 1 L
d. 1 mole sodium phosphate in 1 L
Net Ionic Equation for HF and NaOH
Balanced net ionic equation for HF + NaOH in water.
a. HF (aq)→ H+(aq) + F–(aq)
b. H+(aq) + OH–(aq) → H2O(l)
c. HF (aq) + OH–(aq) → H2O(l) + F–(aq)
d. HF(aq) + NaOH(aq) → H2O(l) + NaF(aq)
Classified as Nonelectrolyte
Which can be classified as nonelectrolyte?
a. NaCl
b. Cl2
c. HCl
d. CH3COOH
Lead(II) Nitrate and Sodium Chloride Reaction
Net ionic equation:
a. Pb2+(aq) + 2Cl−(aq) → PbCl2(s)
b. Na+(aq) + Cl−(aq)→ NaCl(s)
c. Pb2+(aq) + 2NO3−(aq) → Pb(NO3)2(s)
d. Na+(aq) + NO3−(aq)→ NaNO3(s)
Solubility Rules
All salts of Group IA and ammonium are soluble.
All nitrates, chlorates, and acetates are soluble.
All halides are soluble except Ag(I), Cu(I), Pb(II), and Hg(I).
All sulfates are soluble except BaSO4, PbSO4, and SrSO4.
All carbonates, phosphates, and sulfites are insoluble, except those of Group IA and ammonium.
All oxides and hydroxides are insoluble except for Group IA, Ca, Sr, and Ba.
All sulfides are insoluble except for Group IA and IIA elements and ammonium.
Fluoride salts are frequently insoluble, though Group I fluoride salts are soluble.