Chemical Reactions and Stoichiometry Flashcards
What are chemical reactions
The process by which reactants are chemically converted into products.
What is involved in a chemical reaction?
Breaking of bonds and the formation of new bonds.
What is synthesis?
Producing a larger molecule out of multiple smaller molecules.
What is decomposition?
Breaking of a large molecule into multiple smaller molecules.
What is single replacement?
When an element is substituted into a molecule for another.
What is double replacement?
When the reactants break up and swap places twice.
What is precipitation?
A double replacement reaction that results in the production of an insoluble solid.
What is combustion?
The reaction of a substance with oxygen in the presence of heat to form oxides.
What is oxidation-reduction?
A reaction that involves the transfer of electrons from one reactant to the other to form products.
What is hydrolysis?
A reaction of a substance with water.
What is neutralisation?
The reaction of an acid with a base to form a salt.
What is condensation?
A reaction that involves the production of a new substance and water.
What is a word equation?
A chemical equation where the reactants and products are written as words.
What is a symbol equation?
A chemical equation where the reactants and products are written as their ionic or molecular formulae.
What is an ionic equation?
A chemical equation where the cations and anions that are in the same state in the reactants as they are in the products are omitted.
What is the law of conservation of mass?
During a chemical reaction, atoms cannot be created or destroyed.
What is balancing chemical equations?
The process of ensuring the number of atoms of each element are the same on each side of a chemical reaction.
What is enthalpy?
The total energy of a chemical system.
What is the law of conservation of energy?
Energy in a chemical reaction cannot be created or destroyed but changed into different forms.
What is chemical potential energy?
The energy stored within the bonds of a substance.
What is chemical kinetic energy?
The energy that is due to particle motion.
How can the change in enthalpy of a chemical reaction be determined.
▲H = H of products - H of reactants
What is an endothermic process?
When energy is absorbed breaking bonds.
What is an exothermic process?
When energy is released forming bonds.
If the total energy required to break bonds in the reactants is more than the total energy released when new bonds are formed in the products, it is…
an endothermic reaction.
The change in enthalpy of an endothermic reaction is…
positive.
If the total energy required to break bonds in the reactants is less than the total energy released when new bonds are formed in the products, it is…
an exothermic reaction.
The change in enthalpy of an exothermic reaction is…
negative.
What is a thermochemical equation?
A chemical equation that shows the energy absorbed or released.
Is it an endothermic or exothermic reaction?
2H2(g) + O2(g) -> 2H2O(l) ΔH = -522kJ
Exothermic reaction.
Is it an endothermic or exothermic reaction?
2H2(g) + O2(g) -> 2H2O(l) + 522kJ
Exothermic reaction.
Is it an endothermic or exothermic reaction?
CO2(g) -> C(s) + O2(g) ΔH = +394kJ
Endothermic reaction.
Is it an endothermic or exothermic reaction?
CO2(g) + 394kJ -> C(s) + O2(g)
Endothermic reaction.
What is formula mass?
The total sum of the atomic masses.
How can formula mass be calculated?
Adding up the atomic masses of the elements involved.
What is the unit for formula mass?
gmol^-1
How do you calculate the % elemental composition?
=Atomic mass of element * number of atoms in substance/formula mass of compound
