General Chemistry I — 2020 Past Questions

University of Ilorin CHM101: 60 questions.

Topics: Kinetic theory of matter, Periodicity and building up of the periodic table, Chemical bonding and intermolecular forces, Elementary thermochemistry, Modern electronic theory of atoms, Properties of gases, Electronic configuration, Chemical equations and stoichiometry, Structure of solids, Redox reactions and introduction to electrochemistry, Atoms, elements, molecules, Radioactivity

Which element in s-block is not a metal?
1. Hydrogen
2. Sodium
3. Lithium
4. Magnesium
What order is the graph of log[A] against t linear?
1. First
2. Second
3. Zero
4. Third
Cathode rays deflect towards
1. Negative electrode
2. Undeviated
3. Positive electrode
4. Both electrodes
The number of molecules in 4.0g of Oxygen is
1. 1.505 × 10²³
2. 7.525 × 10²²
3. 4.525 × 10²³
4. 3.538 × 10²²
A+B → C. R=k[A]. Which is incorrect?
1. Rate depends on [A]
2. Doesn't depend on [B]
3. Unit of k is s⁻¹
4. Graph of [A] vs t is linear
Which of these are examples of cohesive forces that binds molecules?
1. Covalent
2. Metallic
3. All of the above
4. Ionic
Determine the half-life of a zero-order reaction if [A]₀ = 1.2M and k₀ = 0.00625 M/s
1. 625s
2. 69s
3. 96s
4. 62500s
Which reaction represents zero-order?
1. k = 2.3 M⁻¹s⁻¹
2. k = 1.8 Ms⁻¹
3. k = 0.75 s⁻¹
4. k = 0.87 Ms⁻²
The speed of a chemical reaction
1. Is constant regardless of temperature
2. Is independent of surface area of solids
3. Between gases is always extremely rapid
4. Between ions in solution is extremely rapid
The lanthanide elements are in which period?
1. 6
2. 4
3. 7
4. 5
When two reactants are involved, which is impossible?
1. First order
2. Second order
3. Unimolecular
4. Bimolecular
What is the IUPAC name for Ca₃P₂?
1. Calcium phosphate
2. Carbon phosphate
3. Calcium(III) phosphate
4. Copper(II) phosphate
Find the molecular formula of a hydrocarbon (empirical formula CH₂) with mass 2.1g occupying 1120cm³ at STP.
1. C₃H₆
2. C₂H₄
3. CH₄
4. CH₂
An element Y (mass number 63, atomic number 29) has:
1. p=29, n=34, e=29
2. p=63, n=29, e=63
3. p=29, n=92, e=29
4. p=29, n=34, e=34
Which has the highest vapor density?
1. Water
2. Glass
3. Diethyl ether
4. Ethanol
An element ³²Y is in period ___ and group ___.
1. 4, 14
2. 3, 7
3. 3, 1
4. 4, 2
A radioactive element (t₁/₂ = 1570s) decays at 4710s. What fraction remains?
1. 1/8
2. 1/4
3. 1/2
4. 1/16
Which bond does not exist in solids?
1. Electrovalent
2. Ion-dipole
3. None of these
4. Dipole-dipole
Newlands' periodic table contained ___ elements and ___ periods.
1. 55, 6
2. 62, 6
3. 60, 6
4. 56, 6
Which is an exothermic process?
1. Condensation of water
2. Boiling of water
3. Sublimation of water
4. Melting of ice
A first-order reaction is 40% complete in 50 mins. When will it be 80% complete?
1. 178 min
2. 120 min
3. 210 min
4. 250 min
In which order is half-life increased if [A]₀ is doubled?
1. Zero
2. First
3. Second
4. Third
Which foil was used in Rutherford's experiment?
1. Gold
2. Silver
3. Platinum
4. Aluminum
What is the unit of the rate constant for a second-order reaction?
1. s⁻¹
2. L²mol⁻²s⁻²
3. Lmol⁻¹s⁻¹
4. L⁻¹mols⁻¹
The element with atomic number 38 is in the same group as ___.
1. Na
2. Cl
3. Ca
4. He
For the rate law r = [A][B]², what is the reaction order?
1. Zero
2. First
3. Second
4. Third
An exothermic change ___ heat and has a ___ enthalpy change.
1. Releases, negative
2. Absorbs, negative
3. Releases, positive
4. Absorbs, positive
Which is not a member of Döbereiner's Triad?
1. Ba
2. Be
3. Ca
4. Sr
Gases are ___.
1. Highly compressible
2. Low density
3. Particles in constant chaotic motion
4. All of the above
What is the formula for Potassium Iron(III) tetraoxosulphate(VI) hexahydrate?
1. KFe(SO₄)₂·6H₂O
2. KFe(SO₃)₂·6H₂O
3. KFe(SO₄)₂·7H₂O
4. KFeSO₄·6H₂O
50X is in the same group as
1. 6C
2. 11Na
3. 17Cl
4. 13Al
What is the formula for aluminum trioxosulphate(IV)?
1. Al₂(SO₃)₂
2. AlSO₄
3. Al₂(SO₃)₃
4. Al₂(SO₄)₃
Which is similar to Ar?
1. 25Mn⁷⁺
2. 11Na⁺
3. 13Al³⁺
4. 35Br⁻
What is not a reference electrode?
1. Hydrogen electrode
2. Membrane electrode
3. Silver electrode
4. Calomel electrode
Calculate the molar heat capacity of 100g water (ΔT = 2K, q = 836J, H=1, O=16).
1. 75.24 J/mol·K
2. 54.25 J/mol·K
3. 65.93 J/mol·K
4. 66.33 J/mol·K
If the original concentration in a zero-order reaction is reduced from 1.5 M to 1.0 M, what happens to the half-life?
1. The half-life changes when the original concentration is reduced to 1.0 M
2. The half-life is decreased when the original concentration is reduced to 1.0 M
3. The half-life is increased when the original concentration is reduced to 1.0 M
4. The half-life is unaltered when the original concentration is reduced to 1.0 M
For the reaction 2A + B → 2C with rate equation: Rate = k[A]²[B], identify the correct orders
1. Order w.r.t A=1, overall=1
2. Order w.r.t A=2, overall=2
3. Order w.r.t A=2, overall=3
4. Order w.r.t B=2, overall=2
For the reaction A + B → C with R = k[A], which statement is incorrect?
1. Rate depends on [A]
2. Rate doesn't depend on [B]
3. Unit of k is s⁻¹
4. Graph of [A] vs t is linear
Which are examples of cohesive forces that bind molecules?
1. Covalent
2. Metallic
3. Ionic
4. All of the above
Bonds that can exist in liquids include:
1. Covalent
2. Dipole-Dipole
3. Ion-Dipole
4. Hydrogen
Determine the half-life of a zero-order reaction with [A]₀=1.2M and k₀=0.00625 M/s
1. 625s
2. 69s
3. 96s
4. 62500s
Which represents a zero-order reaction based on rate constant units?
1. k = 2.3 M⁻¹s⁻¹
2. k = 1.8 M·s⁻¹
3. k = 0.75 s⁻¹
4. k = 0.87 M·s⁻²
For what order is a graph of log[A] vs t linear?
1. First
2. Second
3. Zero
4. Third
Why did most alpha particles pass through the metal foil undeflected?
1. Most of the atom is empty space
2. Most of the atom is filled space
3. Most of the atom is fluid-filled space
4. None of the above
Calculate the electrochemical cell potential for Cu²⁺/Cu (+0.10V) and Zn²⁺/Zn (-0.44V)
1. -0.54V
2. +0.34V
3. +0.54V
4. -0.34V
Which bond does not exist in solids?
1. Electrovalent
2. Ion-dipole
3. Dipole-dipole
4. None of these
Which bonds exhibit cohesive forces?
1. Metallic
2. Ionic
3. Covalent
4. All of the above
In which reaction order does half-life increase when [A]₀ is doubled?
1. Zero
2. First
3. Second
4. Third
A first-order reaction is 40% complete in 50min. When will it be 80% complete?
1. 178min
2. 158min
3. 168min
4. 134min
Calculate temperature when ethanol's vapor pressure is 760torr (ΔHvap=40.5kJ/mol, P₁=115torr at T₁=307.9K)
1. 351.69K
2. 341.69K
3. 345.78K
4. 349.82K
Calculate molar heat capacity of 100g water (q=836J, ΔT=2K)
1. 75.24 J/mol·K
2. 234.56 J/mol·K
3. 657.75 J/mol·K
4. 565.67 J/mol·K
Which principle states no two electrons can have identical quantum numbers?
1. Aufbau's
2. Pauli's exclusion
3. Hund's
4. Neil Bohr's
Which element is in the same group as 51Sb?
1. 11Na
2. 7N
3. 10Ne
4. 19K
Which is isoelectronic with Ar?
1. 11Na⁺
2. 11Na
3. 17Cl⁻
4. 12Mg
For rate law r = [A][B]², what is the reaction order?
1. Zero
2. First
3. Second
4. Third
Who left space for undiscovered elements in his periodic table?
1. Döbereiner
2. Mendeleev
3. Newlands
4. None of the above
The decomposition of dimethylether at 504°C is first-order with t₁/₂ = 1570s. What fraction remains after 4710s?
1. 1/3
2. 1/6
3. 1/8
4. 1/16
If atom X with six electrons in its outermost shell combines with atom Y with one electron in its outermost shell to form an ionic compound, then:
1. six atoms of X will combine with one of Y
2. two atoms of X will combine with six of Y
3. one atom of X will combine with two of Y
4. two atoms of X will combine with one of Y
Calculate ΔH at 298.15K for the reaction: 2Na(s) + 2H₂O(l) → 2NaOH(s) + H₂(g). Given ΔH°f[H₂O(l)] = -285.8 kJ/mol and ΔH°f[NaOH(s)] = -426.8 kJ/mol.
1. -291.9 kJ
2. -281.9 kJ
3. -271.9 kJ
4. +281.9 kJ
The total amount of energy in the universe is constant and is referred to as the:
1. First law of thermodynamics
2. Second law of thermodynamics
3. Third law of thermodynamics
4. A and C are correct

General Chemistry I — 2020 Past Questions

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