SEARCH
You are in browse mode. You must login to use MEMORY

   Log in to start

QCAA Chemistry 2023 Units 1-4


🇬🇧
In English
Created:


Public
Created by:
Antoni T


5 / 5  (2 ratings)



» To start learning, click login

1 / 25

[Front]


Define electronegativity
[Back]


The tendency for an atom of a given chemical element to attract shared electrons when forming a chemical bond

Practice Known Questions

Stay up to date with your due questions

Complete 5 questions to enable practice

Exams

Exam: Test your skills

Test your skills in exam mode

Learn New Questions

Dynamic Modes

SmartIntelligent mix of all modes
CustomUse settings to weight dynamic modes

Manual Mode [BETA]

Select your own question and answer types
Specific modes

Learn with flashcards
Complete the sentence
Listening & SpellingSpelling: Type what you hear
multiple choiceMultiple choice mode
SpeakingAnswer with voice
Speaking & ListeningPractice pronunciation
TypingTyping only mode

QCAA Chemistry 2023 Units 1-4 - Leaderboard

0 users have completed this course. Be the first!

No users have played this course yet, be the first


QCAA Chemistry 2023 Units 1-4 - Details

Levels:

Questions:

171 questions
🇬🇧🇬🇧
Define electronegativity
The tendency for an atom of a given chemical element to attract shared electrons when forming a chemical bond
Define ionisation energy
The amount of energy required to remove an electron from an isolated atom or molecule.
Define valency
The ability of an atom to form chemical bonds with other atoms
What is the trend of ionisation energy?
Ionization energy increases moving from left to right across an element period (This is due to valence shell stability). Ionization energy of the elements within a group generally decreases from top to bottom (This is due to electron shielding).
What is the trend of electronegativity
Electronegativity decreases down a group and increases across a period
What is the trend of valency?
Valency first increases and then decreases as we go from left to right in a period but remains the same in a group.
Define a metallic element
Any chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc
Define non-metallic elements
A chemical element (such as boron, carbon, or nitrogen) that lacks the characteristics of a metal.
Define an alkali metal
Very reactive chemical species that readily lose their one valence electron to form ionic compounds with nonmetal elements
Define a halogen
They are reactive non-metallic elements that form strongly acidic compounds with hydrogen.
Define Aufbau's principle
An electron enters the orbital with lowest energy first and subsequent electrons are fed in the order of increasing energies.
Define Hund's rule
Every orbital is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.
Define Pauli's exclusion principle
No more than two electrons can occupy the same orbital and two electrons in the same orbital must have opposite spins
Define electrostatic forces
The attractive or repulsive force between two electrically charged objects.
Define valence electrons
The electrons in the outermost shell, or energy level, of an atom.
Define valency
The number of other atoms with which an atom of the element can combine.
Define electron lone pairs
A pair of valence electrons that in a covalent bond are not exchanged with another atom
What are the types of bonding?
Ionic, covalent and metallic
Define ionic bonding
A chemical connection in which one atom loses valence electrons and gains them from another
Define covalent bonding
The mutual sharing of one or more pairs of electrons between two atoms.
Define metallic bonding
A chemical bond formed between positively charged atoms in which the free electrons are shared among a lattice of cations.
What is the formula for relative atomic mass (RAM)?
∑ isotope mass x isotope abundance / 100.
What is the isotope abundance formula?
Average atomic mass/∑ isotope mass
Define a pure substance
A form of matter that has a constant composition and properties that are constant throughout the sample.
Define a heterogenous mixture
A mixture in which the composition is not uniform throughout the mixture.
Define a homogenous mixture
A mixture in which the composition is uniform throughout the mixture.
Define distillation
The process involving the conversion of a liquid into vapour that is subsequently condensed back to liquid form
Define an ionic compound
Neutral compounds made up of positively charged ions called cations and negatively charged ions called anions
Define an allotrope
The existence of a substance and especially an element in two or more different forms usually in the same phase.
Define a metallic lattice
The type of bond that is formed to create the structure of metals
Define giant covalent networks
A three-dimensional structure of atoms that are joined by covalent bonds. Substances with giant covalent structures are solids with very high melting points
Define a hydrocarbon
An organic compound containing only carbon and hydrogen.
Define an alkane
Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds. This makes them relatively unreactive
Define a alkene
Alkenes are a homologous series of hydrocarbons that contain a carbon-carbon double bond.
Define a single displacement reaction
A reaction in which one element is substituted for another element in a compound
Define a double displacement reaction
Where two compounds react, and positive ions and the negative ions of the two reactants switch places, forming two new compounds or products.
Define a combustion reaction
A reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat
Define a decomposition reaction
Processes in which chemical species break up into simpler parts
Define a redox reaction
A chemical reaction that takes place between an oxidizing substance and a reducing substance.
Define a combination reaction
A reaction in which two reactants combine to form one product
State the law of conservation of energy
The amount of energy is neither created nor destroyed.
Define kinetic energy
The energy of motion, observable as the movement of an object, particle, or set of particles
Define an exothermic reaction
When energy is transferred to the surroundings
Define an endothermic reaction
Chemical reactions in which the reactants absorb heat energy from the surroundings to form products.
Define bond enthalpies
The amount of energy stored in a bond between atoms in a molecule.
Define specific heat capacity
The energy required to increase temperature of material of a certain mass by 1°C
Define heat change
The transfer of energy from one body to another as a result of a difference in temperature or a change in phase.
Define molar mass
The sum of the total mass in grams of the atoms present to make up a molecule per mole
Define a mole
The amount of substance containing the same number of molecules as there are atoms in exactly 12 g of 12C.
Define relative atomic mass
The weight in grams of the number of atoms of the element contained in 12.00 g of carbon-12
Define empirical formula
Chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule
Define molecular formula
Chemical formula that gives the total number of atoms of each element in each molecule of a substance
Define the VSEPR theory
A model used to predict 3-D molecular geometry based on the number of valence shell electron bond pairs among the atoms in a molecule or ion
What are the primary molecular shapes?
Linear, bent, trigonal planar, tetrahedral, pyramidal
Define dispersion forces
A force acting between atoms and molecules that are normally electrically symmetric and are the weakest intermolecular attractive forces.
Define dipole-dipole attraction
Attractive forces between the positive end of one polar molecule and the negative end of another polar molecule.
Define hydrogen bonding
An attraction between a hydrogen atom in one polar molecule and a small electronegative atom in usually another molecule of the same or a different polar substance.
State STP (standard temperature and pressure)
Temperature of 273K (0 °C) and an absolute pressure of exactly 105 Pa
Define the kinetic theory of gases
That all matter is made of small particles that are in random motion and that have space between them.
State the ideal gas law
PV = nRT (P = pressure, V= volume, n= amount of substance, R=ideal gas constant, T=temperature)
Define Boyle's law
That the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature.
Define Charles law
That the volume of an ideal gas at constant pressure is directly proportional to the absolute temperature.
Define Gay Lussac's law
That the volumes of gases undergoing a reaction at constant pressure and temperature are in a simple ratio to each other and to that of the product.
Define Avogadro's law
That equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
Define the relation between pressure and temperature
The pressure of a given amount of gas is directly proportional to the temperature at a given volume.
Define the relation between pressure and volume
The volume of a fixed amount of a gas is inversely proportional to its pressure.
Define the relation between temperature and volume
The volume of a given amount of gas is directly proportional to its temperature
Define molarity
The moles of a solute per liters of a solution
Define a solution
A type of homogeneous mixture composed of two or more substances.
Define a solvent
A substance that dissolves a solute, resulting in a solution.
Define a saturated solution
A solution in which the maximum amount of solvent has been dissolved
Define an unsaturated solution
A solution in which more solute can be dissolved.
Define a supersaturated solution
When the concentration of a solute exceeds the concentration specified by the value of solubility at equilibrium.
Define a precipitate
A substance separated from a solution or suspension by chemical or physical change
Define solubility
The ability to be dissolved, especially in water.
Define a solubility curve
Graphic representation of the variation with changing temperature of the solubility of a given substance in a given solvent.
Define pH
A quantitative measure of the acidity or basicity of aqueous or other liquid solutions
Define an Arrhenius base
Any species that increases the concentration of hydroxide ions
Define an Arrhenius acid
A compound that increases the Hydronium ion concentration in aqueous solution.
Define collision theory
Theory used to predict the rates of chemical reactions, particularly for gases
Define Maxwell-Boltzmann distribution
Describes the distribution of speeds among the particles in a sample of gas at a given temperature.
Define activation energy
The minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.
Define energy profile diagrams
Shows whether a reaction is exothermic or endothermic
Define an open chemical system.
Allowing matter and energy to be exchanged with the surroundings.
Define a closed chemical system.
Allowing energy, but not matter, to be exchanged with the surroundings.
Define chemical equilibrium.
The state in a reversible chemical reaction where the rate of the forward reaction is equal to the reverse reaction, resulting in a stable concentration of reactants and products over time.
What factors affect equilibrium?
Temperature, pressure, concentrations of reactants and products, and the presence of catalysts.
What is the effect of temperature change on chemical systems at equilibrium?
Considering the enthalpy change for the forward and reverse reactions; an endothermic forward reaction will shift to the right with increasing temperature, while an exothermic forward reaction will shift to the left.
Define Le Châtelier’s principle.
If a system in equilibrium is subjected to a change in temperature, pressure, or concentration, the system will adjust to counteract the change and restore equilibrium.
What is the effect of changing concentration and pressure on chemical systems at equilibrium (applying collision theory).
Shifts the chemical equilibrium of a reaction by affecting the rate of forward and reverse reactions based on collision theory; increasing concentration or pressure favors side with less moles of gas, while decreasing concentration or pressure shifts the equilibrium in the direction to oppose the change.
State the formula for equilibrium constant (Kc)
?c =[C]^c x [D]^d / [A]^a x [B]^b
Deduce the extent of a reaction from the magnitude of the equilibrium constant.
Larger values indicate a more complete conversion of reactants to products at equilibrium.
Define an acid (according to the Brønsted–Lowry definition)
Acids are substances that act as proton donors in a chemical reaction.
Define a base (according to the Brønsted–Lowry definition)
Bases are substances that act as proton receivers in a chemical reaction.
Define the term monoprotic
"Monoprotic" refers to an acid or base that can donate or accept only one proton (H+) in a chemical reaction.
Define the term polyprotic
"Polyprotic" refers to an acid or base that can donate or accept more than one proton (H+) in a chemical reaction.
Distinguish between strong and weak acids and bases in terms of the extent of dissociation, reaction with water and electrical conductivity.
Strong acids and bases dissociate completely in water, leading to a high degree of ionization, strong reaction with water, and high electrical conductivity. Weak acids and bases partially dissociate, resulting in lower ionization, weaker reaction with water, and lower electrical conductivity.
Define what a 'strong' acid and base is.
Strong acids and bases fully ionize or dissociate in water, resulting in high concentrations of hydrogen ions (H+) for strong acids and hydroxide ions (OH-) for strong bases
Define what is meant by 'concentrated acids and bases'.
Concentrated acids and bases refer to solutions with a large amount of acid or base dissolved in water regardless of their ionization or dissociation properties.