Chemistry flash cards (AQA)

What is the atomic number of an element?

The atomic number is the number of protons in the nucleus of an atom.

What is an isotope?

An isotope is a variant of an element that has the same number of protons but a different number of neutrons.

Define relative atomic mass.

Relative atomic mass is the weighted average mass of an atom of an element compared to 1/12 of the mass of a carbon-12 atom.

What does the pH scale measure?

The pH scale measures the acidity or alkalinity of a solution, ranging from 0 (highly acidic) to 14 (highly alkaline), with 7 being neutral.

What is a mole in chemistry?

A mole is a quantity that contains Avogadro's number of particles, approximately 6.02 x 10²³.

What is the formula for calculating molar mass?

Molar mass is calculated as the sum of the masses of the individual elements in a compound, measured in grams per mole.

What are the three states of matter?

The three states of matter are solids, liquids, and gases.

What is the Law of Conservation of Mass?

The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction.

What is a covalent bond?

A covalent bond is a chemical bond formed when two atoms share one or more pairs of electrons.

What is an ionic bond?

An ionic bond is a chemical bond formed through the electrostatic attraction between oppositely charged ions.

What is a catalyst?

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.

What triggers a chemical reaction?

A chemical reaction is triggered by factors like temperature, concentration, surface area, and the presence of a catalyst.

What is an endothermic reaction?

An endothermic reaction is a reaction that absorbs heat from its surroundings.

What is an exothermic reaction?

An exothermic reaction is a reaction that releases heat to its surroundings.

How is concentration calculated?

Concentration is calculated by dividing the amount of solute by the volume of the solution.

What is electrolysis?

Electrolysis is a process that uses electrical energy to drive a non-spontaneous chemical reaction.

How do acids react with metals?

Acids typically react with metals to produce hydrogen gas and a salt.

What is the role of indicators in chemistry?

Indicators are substances that change color in response to changes in pH, thus indicating acidity or alkalinity.

What are the products of the complete combustion of hydrocarbons?

The products of complete combustion of hydrocarbons are carbon dioxide and water.

Define the term 'oxidation'.

Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.

Define the term 'reduction'.

Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.

What is a homologous series?

A homologous series is a group of organic compounds that share the same functional group and have similar chemical properties.

What is a functional group?

A functional group is a specific group of atoms within a molecule that is responsible for its characteristic chemical reactions.

What is the general formula for alkanes?

The general formula for alkanes is CnH2n+2.

What are the products of the reaction between an acid and a carbonate?

The products are salt, water, and carbon dioxide.

What is the process of crystallization used for?

Crystallization is used to separate a pure solid from a solution.

Define solubility.

Solubility is the ability of a substance to dissolve in a solvent at a given temperature and pressure.

What is combustion?

Combustion is a chemical reaction that occurs between a fuel and an oxidant, producing heat and often light.

What is an alkene?

An alkene is a hydrocarbon that contains at least one carbon-carbon double bond.

Define polymerization.

Polymerization is the process of joining smaller molecules (monomers) to form larger, more complex molecules (polymers).

What is an empirical formula?

An empirical formula shows the simplest whole number ratio of the elements in a compound.

What is a molecular formula?

A molecular formula shows the actual number of atoms of each element in a molecule.

What is the greenhouse effect?

The greenhouse effect is the trapping of the sun's warmth in the Earth's atmosphere due to greenhouse gases.

What happens during a displacement reaction?

In a displacement reaction, one element displaces another in a compound.

What is the ideal gas law?

The ideal gas law formulates the relationship between pressure, volume, temperature, and number of moles of a gas: PV = nRT.

What is the purpose of titration?

Titration is used to determine the concentration of a solution by reacting it with a solution of known concentration.

What are ionic compounds?

Ionic compounds are chemical compounds composed of ions held together by ionic bonds.

What is the difference between a strong acid and a weak acid?

A strong acid completely ionizes in solution, while a weak acid only partially ionizes.

What is a saturated solution?

A saturated solution is a solution that contains the maximum amount of solute that can dissolve at a specific temperature.

What is distillation?

Distillation is a separation technique that relies on differences in boiling point.

What are the three types of rock in the rock cycle?

The three types of rock are igneous, sedimentary, and metamorphic.

Define the term 'thermochemistry'.

Thermochemistry is the study of the heat absorbed or released during chemical reactions.

What is acid rain?

Acid rain is precipitation that has a lower pH than normal, primarily due to sulfur dioxide and nitrogen oxides in the atmosphere.

What are renewable resources?

Renewable resources are natural resources that can be replenished naturally over time.

What is enthalpy?

Enthalpy is a measure of the total heat content of a system.

What is a redox reaction?

A redox reaction involves the transfer of electrons between two species, where one is oxidized and the other is reduced.

What is the significance of catalysts in industrial processes?

Catalysts increase the efficiency of reactions, reduce energy consumption, and lower production costs.

What are the advantages of using hydrogen as a fuel?

Hydrogen produces clean energy with water as the only byproduct, and it can be replenished from water.

Define electrochemical cell.

An electrochemical cell is a device that converts chemical energy into electrical energy, or vice versa.

What is a balanced equation?

A balanced equation has the same number of atoms of each element on both sides of the equation.

What is the impact of carbon dioxide on global warming?

Carbon dioxide traps heat in the atmosphere, contributing to the greenhouse effect and climate change.

What is an ester?

An ester is a chemical compound formed from the reaction of an alcohol and a carboxylic acid, often with a fruity smell.

How do you determine the reactivity series?

The reactivity series ranks metals based on their ability to displace other metals from solutions of their ions.

What is a solvation shell?

A solvation shell is a layer of solvent molecules that surround a solute particle in solution.

What is the purpose of a reaction profile?

A reaction profile graphically represents the energy changes during the course of a chemical reaction.

What are alcohols?

Alcohols are organic compounds containing one or more hydroxyl (-OH) functional groups.

What is a greenhouse gas?

A greenhouse gas is a gas that contributes to the greenhouse effect by absorbing infrared radiation.

What are the main components of air?

The main components of air are nitrogen (78%), oxygen (21%), and trace amounts of other gases.

What is a chemical equilibrium?

A chemical equilibrium is the state in which the rate of the forward reaction equals the rate of the reverse reaction.

Define 'sublimation'.

Sublimation is the process where a solid changes directly into a gas without going through the liquid phase.

What is an amine?

An amine is a compound derived from ammonia by replacing one or more hydrogen atoms with organic groups.

What is hydrolysis?

Hydrolysis is a chemical reaction where water is used to break down a compound.

What are reactants in a chemical reaction?

Reactants are the starting materials in a chemical reaction that undergo a change to form products.

What is the thermal decomposition?

Thermal decomposition is a chemical reaction where a compound breaks down into simpler compounds or elements when heated.

What is the concept of limiting reactants?

The limiting reactant is the reactant that is completely consumed first in a chemical reaction.

What are transition metals?

Transition metals are elements found in the d-block of the periodic table, known for their ability to form variable oxidation states.

How does temperature affect reaction rates?

Generally, an increase in temperature increases the rate of reaction as particles move faster and collide more frequently.

What is the formula for calculating percentage yield?

Percentage yield is calculated by (actual yield/theoretical yield) x 100.

What is a saturated hydrocarbon?

A saturated hydrocarbon is a hydrocarbon that contains only single bonds between carbon atoms.

What is the role of water in biological systems?

Water is essential for biochemical reactions and processes, serving as a solvent, temperature regulator, and reactant.

What are signs of a chemical reaction?

Signs of a chemical reaction include color change, gas production, temperature change, and the formation of a precipitate.

What is a volatile substance?

A volatile substance is one that easily vaporizes at normal temperatures.

Define le Chatelier's principle.

Le Chatelier's principle states that if an external change is applied to a system at equilibrium, the system will adjust to counteract that change.

What is an aldehyde?

An aldehyde is an organic compound containing a functional group with the structure -CHO.

What is a reduction of metal ore?

Reduction of metal ore is the process of extracting a metal from its compound, typically via a chemical reaction with carbon or other reducing agents.

What do we understand by corrosion?

Corrosion is the degradation of materials, usually metals, due to chemical reactions with their environment.

What factors affect solubility?

Temperature, pressure, and the nature of the solute and solvent affect solubility.

What is the role of enzymes in biological reactions?

Enzymes are biological catalysts that speed up chemical reactions in living organisms.

What is a precipitate?

A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.

What is the significance of the pH in biological systems?

pH is crucial in biological systems as it affects enzyme activity, chemical reactions, and overall cellular function.

What are the characteristics of acids?

Acids taste sour, conduct electricity, and produce hydrogen ions (H⁺) in solution.

What happens during a neutralization reaction?

A neutralization reaction occurs when an acid reacts with a base to form water and a salt.

What is a chemical formula?

A chemical formula is a symbolic representation of the composition of a compound, showing the elements present and their ratios.

What is the role of oxygen in combustion?

Oxygen is essential in combustion as it reacts with the fuel to release energy in the form of heat and light.

What are the characteristics of alkali metals?

Alkali metals are soft, highly reactive metals that form hydroxides with water and are found in group 1 of the periodic table.

Define a saturated solution.

A saturated solution contains the maximum concentration of solute that can dissolve in a solvent at a given temperature.

What are primary, secondary, and tertiary alcohols?

Primary alcohols have the hydroxyl group attached to the first carbon atom, secondary to the second, and tertiary to the third carbon.

What are covalent networks?

Covalent networks are large structures where atoms are bonded by covalent bonds in a continuous network.

What happens to gas pressure when volume decreases?

According to Boyle's Law, gas pressure increases when the volume decreases, assuming temperature remains constant.

What is a systematic name in chemistry?

A systematic name is the official name of a chemical compound based on its structure and composition.

What are the physical properties of metals?

Metals are typically shiny, malleable, ductile, and good conductors of heat and electricity.

What is a fundamental unit in chemistry?

A fundamental unit in chemistry is a basic measure such as the meter, kilogram, or second used for measurements.

What does 'aqueous' mean?

Aqueous refers to a solution in which water is the solvent.

What is a chemical change?

A chemical change involves the formation of new substances through a chemical reaction.

What is specific heat capacity?

Specific heat capacity is the amount of heat required to raise the temperature of 1 kg of a substance by 1 degree Celsius.

What defines a strong base?

A strong base completely dissociates in solution, producing hydroxide ions.

How do you determine the molecular weight?

Molecular weight is