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Chemistry Core Concepts Flashcards
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1
Question
What is the mole in chemistry? A) The mass of a substance in grams B) The amount of substance containing Avogadro's number of particles C) The number of atoms in a molecule D) The volume occupied by 1 gram of substance
Page 1
Answer
B) The amount of substance containing Avogadro's number of particles
2
Question
In stoichiometry, what is the first step when solving problems? A) Identify the limiting reactant B) Convert given quantities to moles C) Balance the chemical equation D) Calculate the percent yield
Page 1
Answer
C) Balance the chemical equation
3
Question
What does the term 'limiting reactant' refer to? A) The reactant that produces the most product B) The reactant that is completely consumed first C) The reactant with the highest molar mass D) The reactant added last in the reaction
Page 1
Answer
B) The reactant that is completely consumed first
4
Question
How is the amount of product determined in a reaction? A) By adding the masses of reactants B) Using the mole ratio from the balanced equation C) Dividing by Avogadro's number D) Multiplying by the atomic weights
Page 1
Answer
B) Using the mole ratio from the balanced equation
5
Question
What is the theoretical yield? A) The actual amount of product obtained B) The maximum possible product under ideal conditions C) The yield after purification D) The yield from excess reactant
Page 1
Answer
B) The maximum possible product under ideal conditions
6
Question
Which formula represents percent yield? A) (actual yield / theoretical yield) × 100% B) (theoretical yield / actual yield) × 100% C) actual yield - theoretical yield D) (actual + theoretical) / 2
Page 1
Answer
A) (actual yield / theoretical yield) × 100%
7
Question
In a combustion analysis, what is calculated first? A) Empirical formula B) Molecular formula C) Percentage composition D) Molar mass
Page 1
Answer
A) Empirical formula
8
Question
What is Avogadro's number approximately equal to? A) 6.022 × 10²³ B) 1.008 × 10²³ C) 6.022 × 10²² D) 12.01 × 10²³
Page 1
Answer
A) 6.022 × 10²³
9
Question
Which law states that the volume of a gas is proportional to the number of moles at constant T and P? A) Boyle's Law B) Charles's Law C) Avogadro's Law D) Ideal Gas Law
Page 2
Answer
C) Avogadro's Law
10
Question
What is the photoelectric effect? A) Emission of light by heated objects B) Ejection of electrons from metal by light C) Diffraction of light waves D) Refraction in prisms
Page 2
Answer
B) Ejection of electrons from metal by light
11
Question
Planck's quantum theory proposes that energy is emitted in: A) Continuous waves B) Discrete packets called quanta C) Random bursts D) Infinite amounts
Page 2
Answer
B) Discrete packets called quanta
12
Question
The speed of light is approximately: A) 3 × 10⁸ m/s B) 3 × 10⁶ m/s C) 3 × 10¹⁰ m/s D) 3 × 10⁴ m/s
Page 2
Answer
A) 3 × 10⁸ m/s
13
Question
What is the wavelength of light related to? A) Frequency inversely B) Speed directly C) Energy exponentially D) Color additively
Page 2
Answer
A) Frequency inversely
14
Question
Electromagnetic radiation includes: A) Only visible light B) Waves from radio to gamma rays C) Particles only D) Sound waves
Page 2
Answer
B) Waves from radio to gamma rays
15
Question
What causes atomic spectra lines? A) Continuous emission B) Electron transitions between energy levels C) Molecular vibrations D) Nuclear reactions
Page 3
Answer
B) Electron transitions between energy levels
16
Question
Bohr's model of the atom features electrons in: A) Fixed orbits B) Probabilistic clouds C) Wavy paths D) Random positions
Page 3
Answer
A) Fixed orbits
17
Question
The principal quantum number n determines: A) Shape of orbital B) Energy level and size C) Spin of electron D) Magnetic orientation
Page 3
Answer
B) Energy level and size
18
Question
What is the azimuthal quantum number l? A) 0 to n-1, for orbital shape B) ±1/2 for spin C) 0 to 3 for orientation D) Principal energy
Page 3
Answer
A) 0 to n-1, for orbital shape
19
Question
Magnetic quantum number m_l ranges from: A) -l to +l B) 0 to n C) 1 to 2l+1 D) n to infinity
Page 3
Answer
A) -l to +l
20
Question
Spin quantum number m_s is: A) 0 or 1 B) +1/2 or -1/2 C) l+1 D) n-l
Page 3
Answer
B) +1/2 or -1/2
21
Question
Pauli exclusion principle states that no two electrons can have: A) The same spin B) The same four quantum numbers C) The same energy D) Opposite spins
Page 4
Answer
B) The same four quantum numbers
22
Question
Hund's rule requires maximum: A) Pairing of electrons B) Unpaired electrons with parallel spins C) Opposite spins in orbitals D) Lowest energy first
Page 4
Answer
B) Unpaired electrons with parallel spins
23
Question
The electron configuration of carbon is: A) 1s² 2s² 2p² B) 1s² 2s² 2p⁶ C) 1s² 2s¹ 2p³ D) 1s² 2p⁴
Page 4
Answer
A) 1s² 2s² 2p²
24
Question
For oxygen, the configuration is: A) [He] 2s² 2p⁴ B) [He] 2s² 2p³ C) [He] 2s¹ 2p⁵ D) [He] 2p⁶
Page 4
Answer
A) [He] 2s² 2p⁴
25
Question
What is the noble gas configuration for sodium? A) [Ne] 3s¹ B) [He] 2s² 2p⁶ 3s¹ C) [Ar] 4s¹ D) 1s² 2s² 2p⁶ 3s¹
Page 4
Answer
A) [Ne] 3s¹
26
Question
Lewis structures show: A) Atomic orbitals B) Valence electrons as dots or lines C) Molecular geometry D) Bond angles
Page 5
Answer
B) Valence electrons as dots or lines
27
Question
In covalent bonding, electrons are: A) Transferred B) Shared equally or unequally C) Lost completely D) Gained by nucleus
Page 5
Answer
B) Shared equally or unequally
28
Question
The octet rule suggests atoms tend to have: A) 4 valence electrons B) 8 valence electrons C) 2 valence electrons D) 18 valence electrons
Page 5
Answer
B) 8 valence electrons
29
Question
For \(H_2O\), the Lewis structure has: A) 2 bonds and 2 lone pairs on O B) 3 bonds C) 4 lone pairs D) Double bond
Page 5
Answer
A) 2 bonds and 2 lone pairs on O
30
Question
Resonance structures occur when: A) Bonds are fixed B) Electrons are delocalized C) Octet is exceeded D) Ions form
Page 5
Answer
B) Electrons are delocalized