S1. Models of the particulate nature of matter Flashcards
(90 cards)
1
Q
What are the classifications of matter?
A
Matter can be classified into: Elements, Compounds, and Mixtures.
2
Q
What are elements?
A
Elements (e.g., O₂, Au): Not chemically bonded.
3
Q
What are compounds?
A
Compounds (e.g., H₂O, CO₂): Chemically bonded, can only be separated via chemical reactions.
4
Q
What are mixtures?
A
Mixtures: Not chemically bonded, separable by physical means.
5
Q
What is a homogeneous mixture?
A
Homogeneous: Uniform composition.
6
Q
What is a heterogeneous mixture?
A
Heterogeneous: Non-uniform composition.
7
Q
What are pure substances?
A
Pure substances: Fixed composition and distinct properties (e.g., elements and compounds).
8
Q
What are non-pure substances?
A
Non-pure substances: Varying composition (e.g., mixtures).
9
Q
What is filtration?
A
Filtration: Separates solids from liquids.
10
Q
What is distillation?
A
Distillation: Separates liquids by boiling point.
11
Q
What is condensation?
A
Condensation: gas → liquid.
12
Q
What is sublimation?
A
Sublimation: solid → gas.
13
Q
What is deposition?
A
Deposition: gas → solid.
14
Q
What are endothermic processes?
A
Melting, boiling, sublimation: Endothermic (absorbs energy).
15
Q
What are exothermic processes?
A
Freezing, condensation, deposition: Exothermic (releases energy).
16
Q
What is kinetic energy?
A
Energy due to motion.
17
Q
What is absolute zero?
A
Absolute Zero: 0 K, theoretical point where all particle motion stops.
18
Q
What is the freezing point of water in Celsius and Kelvin?
A
Water freezes at 0°C = 273.15 K.
19
Q
What is the formula to convert Celsius to Kelvin?
A
Formula: T(K) = T(°C) + 273.15.
20
Q
What is heat?
A
Heat: Total energy of particles.
21
Q
What is temperature?
A
Temperature: Average energy per particle.
22
Q
How is heat transfer measured?
A
Heat transfer: Due to temperature difference, measured in joules (J).
23
Q
What is the formula for density?
A
Formula: ρ = mass / volume.
24
Q
What are the units of density?
A
Units: g/cm³.
25
What is atomic number (Z)?
Atomic number (Z): Number of protons.
26
What is mass number (A)?
Mass number (A): Protons + neutrons.
27
What are isotopes?
Isotopes: Same Z, different neutrons → different mass, same chemical properties.
28
What is a cation?
Cation: Positively charged.
29
What is an anion?
Anion: Negatively charged.
30
What is the formula for relative atomic mass (Aᵣ)?
Formula: Aᵣ = [(mass₁ × %abundance₁) + (mass₂ × %abundance₂)] / 100 OR Aᵣ = m₁x + m₂(1 − x).
31
What does mass spectrometry measure?
Mass Spectrometry: Measures mass-to-charge ratio (m/z).
32
What are the key components of mass spectrometry?
Key components: Ionization source, Mass analyzer, Detector.
33
What is emission spectra?
Electrons emit/absorb energy when transitioning between energy levels.
34
What are continuous spectra?
Continuous spectra: All wavelengths (seamless rainbow).
35
What are line spectra?
Line spectra: Discrete wavelengths.
36
What is emission in spectra?
Emission: Bright lines (light emitted).
37
What is absorption in spectra?
Absorption: Dark lines (light absorbed).
38
What is the Lyman series?
Lyman series: n → 1 (UV).
39
What is the Balmer series?
Balmer series: n → 2 (visible).
40
What is the Paschen series?
Paschen series: n → 3 (IR).
41
What is a quantum leap?
Quantum leap: Electron jumps from one level to another.
42
What is ionization energy?
Ionization energy: Energy to remove 1 electron from a gaseous atom.
43
What is the principal quantum number (n)?
Principal quantum number (n): n = 1, 2, 3, ... .
44
What is the maximum number of electrons per energy level?
Max electrons per energy level: 2n².
45
How many electrons can the s sublevel hold?
s: 2 electrons.
46
How many electrons can the p sublevel hold?
p: 6 electrons.
47
How many electrons can the d sublevel hold?
d: 10 electrons.
48
How many electrons can the f sublevel hold?
f: 14 electrons.
49
What is the order of filling for atomic orbitals?
s is filled before d.
## Footnote
Example: 3p⁶ 4s² 3d¹⁰.
50
What are atomic orbitals?
Region with high probability of finding an electron.
51
What is Pauli's Exclusion Principle?
Pauli's Exclusion Principle: No two electrons in the same orbital can have the same quantum numbers.
52
What is the Aufbau Principle?
Aufbau Principle: Electrons occupy lowest energy orbitals first.
53
What is Hund's Rule?
Hund's Rule: Electrons prefer to occupy empty orbitals within the same sublevel before pairing up.
54
What does electron configuration show?
How electrons are arranged in the atomic orbitals of an atom
## Footnote
It follows the order in which electrons fill orbitals of increasing energy.
55
What is the electron configuration of Oxygen (Z = 8)?
1s² 2s² 2p⁴
## Footnote
This configuration indicates the distribution of electrons in various orbitals.
56
What is condensed electron configuration?
A shorthand notation using the previous noble gas to simplify electron configuration
## Footnote
It helps in reducing the complexity of writing full electron configurations.
57
What is the full electron configuration of Sodium (Z = 11)?
1s² 2s² 2p⁶ 3s¹
## Footnote
This shows the distribution of electrons in Sodium's orbitals.
58
What is the condensed electron configuration of Sodium (Z = 11)?
[Ne] 3s¹
## Footnote
[Ne] represents the electron configuration of the nearest noble gas, Neon.
59
What are exceptions or anomalies in electron configuration?
Some elements deviate from expected configurations to achieve greater stability in half-filled or fully filled d sublevels
## Footnote
These anomalies occur in specific elements like Chromium and Copper.
60
What is the electron configuration of Chromium (Cr, Z = 24)?
[Ar] 4s¹ 3d⁵
## Footnote
Chromium's configuration is an exception as it is not 4s² 3d⁴.
61
What is the electron configuration of Copper (Cu, Z = 29)?
[Ar] 4s¹ 3d¹⁰
## Footnote
Copper's configuration is an exception as it is not 4s² 3d⁹.
62
What is the SI unit for amount of substance?
The mole (mol)
## Footnote
The mole is used to quantify the number of entities in a substance.
63
What is Avogadro's constant (Nₐ)?
6.022 × 10²³ mol⁻¹
## Footnote
This is the number of entities in 1 mole of substance.
64
How many atoms are in 1 mol of Na?
6.022 × 10²³ atoms
## Footnote
This is a direct application of Avogadro's constant.
65
What is relative atomic mass (Aᵣ)?
Weighted average mass of an atom compared to 1/12th of a carbon-12 atom
## Footnote
Aᵣ is a dimensionless quantity.
66
What is relative formula mass (Mᵣ)?
Sum of relative atomic masses in a formula unit
## Footnote
Mᵣ is used to calculate the mass of compounds.
67
Calculate the Mᵣ of H₂O.
18.0
## Footnote
Mᵣ of H₂O = 2(1.0) + 16.0.
68
What is molar mass (M)?
The mass of 1 mole of a substance, in g/mol
## Footnote
Molar mass is numerically equal to Mᵣ.
69
What formula relates moles, mass, and molar mass?
n = m / M
## Footnote
Where n = moles, m = mass (g), M = molar mass (g/mol).
70
What does an empirical formula represent?
The simplest whole-number ratio of atoms in a compound
## Footnote
Example: C₆H₁₂O₆ → CH₂O.
71
What does a molecular formula show?
The actual number of atoms of each element in a molecule
## Footnote
Example: CH₂O (empirical) + molar mass = 180 g/mol → C₆H₁₂O₆ (molecular).
72
What is the formula to find molar concentration (c)?
c = n / V
## Footnote
Where c = mol/dm³, n = moles, V = volume in dm³.
73
Convert 100 cm³ to dm³.
0.1 dm³
## Footnote
To convert cm³ to dm³, divide by 1000.
74
What is the molar concentration of 0.5 mol NaCl in 0.25 dm³?
2.0 mol/dm³
## Footnote
This is calculated using c = n / V.
75
What is Avogadro's Law?
Equal volumes of gases at same T and P contain equal numbers of molecules
## Footnote
Gases combine in simple whole-number ratios by volume.
76
What is the molar volume of a gas at STP?
22.7 dm³
## Footnote
This applies at 273 K and 1 atm.
77
How do you determine % composition of an element in a compound?
% = (mass of element / molar mass) × 100
## Footnote
This formula helps in analyzing the composition of compounds.
78
What is the relationship between particles and moles?
n = N / Nₐ
## Footnote
Where N = number of particles and Nₐ = Avogadro's constant.
79
How do you calculate moles from mass?
n = m / M
## Footnote
This is a fundamental calculation in stoichiometry.
80
What is the formula for dilution?
C₁V₁ = C₂V₂
## Footnote
This formula is used to prepare solutions of desired concentrations.
81
What are the key assumptions of the ideal gas model?
*Particles are in constant random motion
*No intermolecular forces
*Particle volume is negligible
*All collisions are elastic
82
When do real gases deviate from ideal behaviour?
*At low temperatures (forces become significant)
*At high pressures (particle volume matters)
Example: CO₂ deviates from ideal at -50°C and high pressure.
83
What is the molar volume of an ideal gas at STP?
*22.7 dm³ per mole
*Conditions: 273 K (0°C) and 1 atm pressure
Example: 2 mol of H₂ gas = 45.4 dm³ at STP
84
What is the ideal gas equation and what do the variables mean?
PV = nRT, where:
P = pressure (Pa)
V = volume (m³)
n = moles
R = 8.31 J/mol·K
T = temperature (K)
85
What is the combined gas law formula?
(P₁V₁)/T₁ = (P₂V₂)/T₂, assuming number of moles is constant.
Use this when a gas changes state but not amount.
86
What is Boyle’s Law and what does its graph look like?
P ∝ 1/V (at constant temperature)
Graph: curved/hyperbolic
As volume decreases, pressure increases.
87
What are the limitations of the ideal gas model?
*Real gases have volume
*Real gases do interact via forces
*Ideal model breaks down at low T, high P
88
How do you use PV = nRT to solve for any variable?
For n: n = PV / RT
For V: V = nRT / P
Convert all values to SI units before calculating
89
How do you calculate the molar mass of a gas using PV = nRT?
Use: M = (mRT) / (PV)
where:
m = mass of gas (g)
M = molar mass (g/mol)
R = 8.31
T in K, V in m³, P in Pa
90
What do the gas laws help us understand in experiments?
*The relationship between P, V, T for gases
*Predicting how gases behave under different conditions
*Finding molar mass or unknown gas identities using experimental data
