Mod 1 Flashcards
(191 cards)
1
Q
What is a mixture?
A
A combination of two or more pure substances in which each retains its individual chemical properties.
2
Q
What are the two types of mixtures?
A
- Heterogeneous Mixtures
- Homogeneous Mixtures
3
Q
Define heterogeneous mixtures.
A
Mixtures where two or more substances intermingle but remain physically separate.
4
Q
Give an example of a heterogeneous mixture.
A
- Dirt + Sand
- Oil + Water
- Salt + Baking Soda
5
Q
What is a suspension?
A
A specific type of heterogeneous mixture where particles settle at the bottom.
6
Q
Define homogeneous mixtures.
A
Mixtures where two or more substances have merged into a uniform phase.
7
Q
Give an example of a homogeneous mixture.
A
- Saltwater
- Copper Sulfate solution
8
Q
What is filtration?
A
A method of separation based on solid vs liquid, where solid impurities are left as residue.
9
Q
What is sedimentation?
A
A method of separation based on different densities of solid vs liquid.
10
Q
What is distillation?
A
A method of separation based on different boiling/condensation points.
11
Q
What is fractional distillation?
A
A method used to separate substances with very small ranges of boiling/condensation points.
12
Q
What does evaporation + crystallisation rely on?
A
Different boiling points and solubility.
13
Q
What is centrifuging?
A
A method of separation based on different densities using centripetal force.
14
Q
What is sieving?
A
A method of separation based on different particle sizes of solids.
15
Q
What is magnetic separation?
A
A method used to separate substances based on their magnetic properties.
16
Q
What is chromatography?
A
A method of separation based on different solubilities of solute.
17
Q
What is the definition of the periodic table?
A
An ordered compilation of all known elements.
18
Q
What are elements?
A
Pure substances that cannot be chemically or physically decomposed.
19
Q
What are compounds?
A
Pure substances that are chemical combinations of two or more different elements.
20
Q
What are periods in the periodic table?
A
Rows that increase in atomic number from left to right.
21
Q
What are groups in the periodic table?
A
Columns where elements share similar chemical properties due to having the same number of valence electrons.
22
Q
What characterizes metals?
A
Good conductors of heat and electricity, malleable, ductile, usually solid at room temperature.
23
Q
What characterizes nonmetals?
A
Usually good insulators, brittle, can be gases, liquids, or solids at room temperature.
24
Q
What characterizes metalloids?
A
Have properties of both metals and nonmetals.
25
What are alkali metals?
Group 1 elements with one valence electron, highly reactive.
26
What are alkaline earth metals?
Group 2 elements with two valence electrons, reactive and oxidize easily.
27
What are transition metals?
Groups 3-12 elements with varying valencies, less reactive than alkali metals.
28
What are halogens?
Group 17 elements with 7 valence electrons, highly reactive and form diatomic molecules.
29
What are noble gases?
Group 18 elements with full valencies, highly unreactive.
30
What is atomic radius?
Half the distance between the centers of two atoms of an element that are touching.
31
What happens to atomic radius moving left to right across a period?
Atomic radius decreases.
32
What is ionisation energy?
The energy required to remove one valence electron from a gaseous atom.
33
What is electronegativity?
The measure of the ability of an atom to attract electrons for chemical bonding.
34
What is the relationship between atomic radius and ionisation energy?
As atomic radius decreases, ionisation energy increases.
35
What are isotopes?
Different versions of an element that have the same number of protons but different numbers of neutrons.
36
What are stable isotopes?
Isotopes that have sufficient binding energy to keep the nucleus together.
37
What are unstable isotopes?
Isotopes that undergo radioactive decay due to an imbalance of neutrons.
38
What is isotope notation?
The representation of isotopes using the element name with a hyphen and mass number or with superscript and subscript in chemical symbols.
39
What is relative atomic mass?
An average of all isotopes of an element, reflecting their abundance.
40
What is a mass spectrometer?
A device that sorts isotopes by atomic mass using electromagnetic fields.
41
What is radioactive decay?
The process by which an unstable atom breaks apart and releases energy as particles or waves.
42
What is half-life?
The time it takes for half the atoms in a substance to decay.
43
What are the three main types of radiation?
* Alpha Radiation
* Beta Radiation
* Gamma Radiation
44
What are transuranium elements?
Elements that are artificially synthesized, such as technetium-95 and promethium-146.
45
What is the half-life of a substance?
A measure of the time it takes for half the atoms in that substance to decay.
46
What are the three main types of radiation?
* Alpha radiation
* Beta radiation
* Gamma radiation
47
What occurs during alpha decay?
An atom emits an alpha particle, which is made of two protons and two neutrons.
48
What changes occur in an atom after alpha decay?
The atomic number decreases by 2, and the mass number decreases by 4.
49
Provide an example of alpha decay.
Uranium-238 transforms into thorium-234.
50
What happens during beta decay?
An atom emits a beta particle, which can be an electron or a positron.
51
What is the effect of beta decay on the atomic number and mass number?
The atomic number increases by 1, and the mass number stays the same.
52
What is positron emission?
Occurs when a proton splits into a neutron and positron, decreasing the atomic number by 1.
53
What is electron capture?
A process where a proton captures an electron and becomes a neutron, decreasing the atomic number by 1.
54
What characterizes gamma radiation?
Occurs when an atom emits gamma rays, usually after alpha or beta decay.
55
What are the properties of alpha, beta, and gamma radiation?
* Alpha rays: Helium nucleus, few cm in air, +2 charge, mass -27, affected by electromagnetic fields
* Beta rays: Electrons, few mm of aluminium, -1 charge, mass -31, affected by electromagnetic fields
* Gamma rays: Photons, many cm of lead, zero charge, zero mass, not affected by electromagnetic fields
56
What is Dalton's model of the atom?
Atoms were indivisible, solid spheres.
57
What does Thompson's model propose?
Electrons are embedded in a positive solid sphere, known as the plum-pudding model.
58
What was discovered in Rutherford's model?
Atoms are mostly empty space with a positive center and electrons floating around.
59
What are the main points of Bohr's model?
* Electrons occupy fixed orbits around the nucleus
* Each orbit has an energy level
* Energy is absorbed or emitted when electrons jump between orbits
60
What is the limitation of Bohr's model?
It can only be applied to atoms with one valence electron.
61
What does Schrodinger's model propose?
Electrons move irregularly, predicting the probability of an electron's location around the atom.
62
What is the Aufbau Principle?
Electrons are added to the lowest energy level until filled, then to the next level.
63
What are subshells in electron configuration?
Groups of atomic orbitals that have distinct shapes and different capacities.
64
What is the maximum electron capacity of an s subshell?
2 electrons.
65
What is the Madelung Rule?
Electrons will fill the lowest energy subshell, even if it is inside a higher shell.
66
What is the purpose of the flame test?
To detect the presence of particular metals based on the color of light emitted.
67
What is the relationship between electronegativity and bonding?
Electronegativity determines how electrons are shared in covalent bonds.
68
What characterizes ionic bonds?
Involves a metal donating electrons to a nonmetal, creating cations and anions.
69
Provide an example of an ionic bond.
Sodium donates its one valence electron to chlorine, forming sodium chloride.
70
What are polyatomic ions?
Molecules composed of bonded atoms that have an overall charge.
71
What characterizes covalent bonds?
Involves sharing electrons between nonmetal atoms.
72
What is the difference between non-polar and polar covalent bonds?
* Non-Polar: Electrons shared equally
* Polar: Electrons shared unequally, creating partial charges
73
What is the criss-cross method?
A method to determine the final product of an ionic bond by swapping oxidation numbers.
74
What is the Criss-Cross Method used for?
To determine the final product of an ionic bond by swapping oxidation numbers of reactants and making them subscripts for the product.
75
What is the oxidation number?
The charge an atom would have if it were an ion.
76
What do atoms with 1, 2, or 3 valence electrons tend to do?
Remove electrons.
77
What oxidation number does Sodium have and why?
+1, because it has one valence electron that it wants to lose.
78
What oxidation number does Fluorine have and why?
-1, because it wants to gain one electron.
79
How is the chemical formula for Potassium Oxide determined?
By combining Potassium (+1) and Oxygen (-2) in a 2:1 ratio, resulting in K2O.
80
What do Lewis Dot Diagrams represent?
Valence electrons and bonds in covalent compounds.
81
In a Lewis Dot Diagram, how are covalent bonds represented?
As lines between atoms.
82
What are non-bonding electron pairs?
Pairs of electrons that are not involved in bonding.
83
What do intramolecular bonds do?
Hold atoms together within a molecule.
84
How do intermolecular forces differ from intramolecular bonds?
Intermolecular forces exist between molecules, while intramolecular bonds exist within a molecule.
85
What are dipole-dipole interactions?
Attractions between the positive dipole of one molecule and the negative dipole of another.
86
What characterizes Hydrogen Bonds?
They occur between hydrogen atoms bonded to oxygen, nitrogen, or fluorine, and are the strongest type of dipole-dipole interactions.
87
What are London Dispersion Forces?
The weakest intermolecular forces that occur due to temporary dipoles formed by electron movement.
88
What is the relationship between bond strength and melting/boiling points?
Stronger bonds require more energy to break, leading to higher melting and boiling points.
89
What is the structure of Ionic Compounds?
They form lattice structures where each cation is surrounded by anions.
90
What is a Formula Unit?
The simplest ratio of ions in an ionic compound.
91
What happens to ionic solids when they are impacted?
They break due to repulsion between aligned like-charged ions.
92
What defines Covalent Molecular compounds?
They exist as discrete molecules with weak intermolecular forces.
93
What distinguishes Covalent Network compounds?
They have strong covalent bonds in a 2D or 3D network.
94
What defines a Metallic bond?
A lattice of positive metal ions held together by delocalized electrons.
95
What are allotropes?
Different structures of the same element that exhibit different properties.
96
What does VSEPR theory explain?
The shape of molecules based on electron configurations and repulsion.
97
How are ionic compounds named?
Cation name first, followed by anion name with appropriate suffix (-ide, -ate, -ite).
98
What prefixes are used in naming covalent compounds?
Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca.
99
What is the general formula for an alkane?
CnH2n+2.
100
What is a mole defined as?
6.022 x 10^23 particles of a compound/element.
101
What is molar mass?
The mass in grams of one mole of a molecule, measured in grams per mole (g/mol).
102
What formula relates number of moles, actual mass, and molar mass?
n = m/MM.
103
Fill in the blank: A mole is defined as _______.
[6.022 x 10^23 particles].
104
True or False: Ionic compounds have high melting and boiling points.
True.
105
What is the molar mass of Sodium?
22.99 g/mol
## Footnote
Sodium has an atomic mass of 22.99 amu.
106
What formula represents the relationship between Moles, Actual Mass, and Molar Mass?
n = m/MM
107
How do you calculate the number of moles from mass and molar mass?
Number of Moles = Mass(g) ÷ Molar Mass(g/mol)
108
What is the formula for calculating moles from the number of particles?
n = N/NA
109
What does n = CV represent?
Number of Moles = Concentration of Solution (moles/litre) * Volume (litres)
110
What is the formula for calculating moles from the volume of gas at STP?
n = Volume of Gas / 22.71 OR 24.79
111
What is the stoichiometric ratio in a chemical reaction?
The ratio between reactants and products as indicated by the coefficients in a balanced equation.
112
What is a limiting reagent?
The substance that is totally consumed when the chemical reaction is complete.
113
What is theoretical yield?
The maximum amount of product that can be produced based on the limiting reagent.
114
Define concentration in terms of solute and solvent.
Concentration refers to the amount of solute divided by the volume of solvent.
115
What is molarity?
Molarity is defined as moles of solute per litre of solvent (n/L).
116
What does Gay-Lussac’s Law of Combining Volumes state?
The volume of gases taking part in a chemical reaction will combine in simple whole number ratios at constant temperature and pressure.
117
What does Avogadro’s Gas Law state about equal volumes of gases?
Equal volumes of different gases contain the same number of molecules at the same temperature and pressure.
118
What is Boyle’s Law?
The pressure exerted by a gas is inversely proportional to its volume when measured at a constant temperature.
119
What is Charles’ Law?
The volume of a gas is directly proportional to its temperature when measured at constant pressure.
120
What does Gay-Lussac’s Pressure and Temperature Law state?
The pressure exerted by a gas is directly proportional to its temperature (in Kelvin) when volume is constant.
121
What is the Ideal Gas Law equation?
PV = nRT
122
What are the assumptions of an Ideal Gas?
Gas molecules move randomly, pressure is due to collisions, all collisions are elastic, no intermolecular forces, and gas molecules take up no volume.
123
What is a standard solution?
A solution of known and fixed concentration made by dissolving a known weight of solute to a specific volume.
124
What is the purpose of primary standards?
They are used to prepare standard solutions and must be pure and easily weighed.
125
What is electrolysis?
The application of an electric current to decompose a compound.
126
What are indicators of a chemical reaction?
* Bubbles
* Colour change
* Change in energy (temperature)
* Appearance of a solid (precipitation)
* Disappearance of a solid
127
Define exothermic reaction.
A reaction where reactants have more energy than products, releasing energy into the surroundings.
128
Define endothermic reaction.
A reaction where energy is taken from the surroundings, with reactants having less energy than products.
129
What is a synthesis reaction?
A reaction where simpler substances combine to form a compound (A + B → AB).
130
What is a displacement reaction?
A reaction involving the swapping of ions between two soluble salt solutions.
131
What is a precipitation reaction?
A reaction where an insoluble salt forms and settles out of solution.
132
What is a decomposition reaction?
A reaction where a compound breaks down into two or more products (AB → A + B).
133
What are the types of decomposition reactions?
* Thermal
* Electrolytic
* Photo Decomposition
134
What occurs in a neutralization reaction?
An acid and a base react to form salt and water.
135
What is the general reaction for an acid reacting with a metal?
Acid + Metal → Salt + Hydrogen gas.
136
What is produced when an acid reacts with a metal carbonate?
Salt + Carbon Dioxide + Water.
137
What is the difference between complete and incomplete combustion?
* Complete combustion: Hydrocarbon + Oxygen → Carbon Dioxide + Water
* Incomplete combustion: Hydrocarbon + Oxygen → Carbon Monoxide + Carbon + Water.
138
What are combustion reactions?
Reactions where flames (light, heat, and sound energy) can be observed and are exothermic
## Footnote
Combustion reactions typically involve hydrocarbons reacting with oxygen.
139
What are corrosion reactions?
Reactions with oxygen that are much slower than combustion reactions
## Footnote
Corrosion is a gradual process that often affects metals.
140
What is incomplete combustion?
Combustion that occurs when there is not enough oxygen
## Footnote
It produces carbon monoxide, carbon, and water.
141
Write the equation for incomplete combustion of a hydrocarbon.
Hydrocarbon + Oxygen → Carbon Monoxide + Carbon + Water
142
What is complete combustion?
Combustion that occurs when there is enough oxygen
## Footnote
It produces carbon dioxide and water.
143
Write the equation for complete combustion of methane.
CH4 + 2O2 → CO2 + 2H2O
144
What are solubility rules?
Guidelines that tell which ions form solids and which remain in their ionic form in aqueous solution.
145
What happens if all ions in a reaction are soluble?
No precipitation reaction occurs.
146
What are the exceptions for soluble salts?
* Salts formed with group 1 cations and NH4+ cations
* Acetates (C2H3O2−), nitrates (NO3−), and perchlorates (ClO4−) are soluble
* Bromides, chlorides, and iodides are soluble
* Sulfates (SO4^2−) are soluble with exceptions for Ca2+, Sr2+, and Ba2+
* Salts containing silver, lead, and mercury (I) are insoluble
* Carbonates (CO3^2−), phosphates (PO4^3−), sulfides, oxides, and hydroxides (OH−) are insoluble.
147
What is the reactivity series of metals?
An arrangement of metals from highest to lowest reactivity.
148
What criteria are used to compare the reactivity of metals?
* Reactivity with oxygen
* Reactivity with water
* Reactivity with dilute solutions of acids
* Reactivity with other metal ions in solutions.
149
What does oxidation mean in a redox reaction?
Loss of electrons, resulting in an increase in oxidation state.
150
What does reduction mean in a redox reaction?
Gain of electrons, resulting in a decrease in oxidation state.
151
What is the mnemonic for remembering redox reactions?
OILRIG: Oxidation Is Loss, Reduction Is Gain.
152
What is an oxidising agent?
The atom that gains electrons and is reduced in a chemical reaction.
153
What is a reducing agent?
The atom that loses electrons and is oxidised in a chemical reaction.
154
How can you identify a redox reaction?
By identifying changes in oxidation numbers of atoms before and after a reaction.
155
What is the process for balancing complex redox reaction equations?
* Split the equation into two half equations (oxidation and reduction)
* Balance elements other than O and H
* Balance oxygen by adding water
* Balance hydrogen by adding H+ ions
* Equalize charges by adding electrons
* Combine half-equations.
156
What are net ionic equations?
Equations that describe reactions in water, excluding spectator ions.
157
What do positive and negative standard reduction potentials indicate?
* Positive voltage: energy released in spontaneous reaction
* Negative voltage: energy required for the reaction to occur.
158
What is a Galvanic/Voltaic cell?
A device that uses redox reactions to create electricity.
159
What is the role of the salt bridge in a galvanic cell?
Allows ions to pass between the cells, balancing charge.
160
What occurs at the anode and cathode in a galvanic cell?
* Anode: oxidation occurs (loss of electrons)
* Cathode: reduction occurs (gain of electrons).
161
What is the rate of reaction?
A measure of how quickly reactants are converted into products.
162
What is collision theory?
For reactions to occur, particles must collide with sufficient energy.
163
What factors can increase the rate of reaction?
* Increasing temperature
* Increasing concentration
* Increasing surface area
* Adding a catalyst
* Increasing pressure.
164
What is kinetic energy's role in collisions?
Particles move faster, increasing the chance of successful collisions.
165
How does increasing concentration affect reaction rates?
More particles of reactant in the same space lead to more collisions.
166
What effect does increasing surface area have on reactions?
More of one reactant is exposed to the other, resulting in more collisions.
167
What is a catalyst?
A substance that speeds up a reaction without being used up.
168
How do catalysts affect activation energy?
They decrease the activation energy required for a reaction.
169
What happens to particles when pressure is increased?
Particles are pushed closer together, increasing collision likelihood.
170
What is the relationship between volume and concentration when pressure increases?
If volume goes down, concentration goes up.
171
What is activation energy?
The minimum amount of energy required for reactants to begin reacting.
172
What does the Maxwell-Boltzmann distribution show?
The likelihood of particles having different velocities at different temperatures.
173
What does an activation energy curve illustrate?
The peak of the curve represents the activation energy required.
174
What is enthalpy?
The energy content of a system.
175
What is the formula for calculating enthalpy?
H = U + PV.
176
What indicates an exothermic reaction in terms of enthalpy change?
ΔH is negative if heat is released.
177
What does Hess's Law state?
Total enthalpy change depends only on initial and final states, not the pathway.
178
What do energy profile diagrams represent?
The energy level of a reaction as it progresses.
179
What signifies an exothermic reaction in terms of energy comparison?
Energy of products < Energy of reactants.
180
What is bond energy?
The amount of energy required to break the bonds of 1 mol of a substance.
181
What is the standard enthalpy of formation?
The change of enthalpy during the formation of 1 mole of a substance from its elements.
182
What is a stepped reaction?
A reaction that occurs in multiple steps.
183
What is a calorimeter used for?
To measure the quantity of heat flow in a chemical reaction.
184
What is molar heat of combustion?
Energy released when 1 mole of a substance undergoes complete combustion.
185
What is molar heat of dissolution?
Energy consumed/released when 1 mol of a substance dissolves in water.
186
What is entropy?
A measure of molecular disorder or randomness in a system.
187
What factors affect entropy?
* Temperature
* Dissolution
* Change in State
188
What defines an open system?
Matter and energy can go outside the system.
189
What is a spontaneous reaction?
A reaction that occurs without external energy once started.
190
What conditions favor spontaneous reactions?
* Decrease in enthalpy
* Increase in entropy
191
True or False: Spontaneity is related to the rate of reaction.
False
