chemisty
Which term describes a reaction where products can react to reform the original reactants?
A reversible reaction
What is the unit used to express the amount of a substance?
The mole (mol)
Which subatomic particle has a positive electrical charge?
A proton particle
In a neutral atom, the number of protons is equal to the number of which other particles?
Electron counts
Materials with a simple molecular structure generally have which property?
Low boiling points
Which material is an example of a giant covalent structure?
Diamond substance
How is the relative formula mass (Mr) of a compound calculated?
By adding atomic masses
The atomic number of an element is determined by the number of which particles?
Protons present
Which type of bonding involves the electrostatic attraction between oppositely charged ions?
Ionic bonding
Which calculation describes percentage yield in a chemical reaction?
(Actual/Theoretical) x 100%
When an acid reacts with a base, what are the typical products formed?
Salt and water
What is the process of using electrical energy to break down compounds?
Electrolysis method
What kind of intermolecular forces exist between simple molecular substances?
Very weak forces
How is the concentration of a solution typically expressed?
Moles per dm³ (mol/dm³)
An ion with a negative charge is formed when an atom does which of the following actions?
Gains an electron
Which of the following is characteristic of metallic bonding?
Delocalized electrons
What is the primary role of a catalyst in a chemical reaction?
To lower activation energy
What is the maximum number of electrons that can occupy the first electron shell?
Two electrons
Why does graphite conduct electricity, unlike diamond?
It has delocalized electrons
What does a limiting reactant in a chemical reaction determine?
The amount of product formed
What is the term for the efficiency of a chemical reaction in converting reactants into useful products?
Atom economy
What are atoms of the same element with different numbers of neutrons called?
Isotopes
A chemical reaction that releases energy to its surroundings, usually as heat, is called which type of reaction?
Exothermic process
What type of chemical change involves the loss of electrons by a substance?
Oxidation process
What generally happens to the rate of reaction when the temperature is increased?
It increases significantly