Chemistry Reading #3 Flashcards
What happens when two or more molecules interact and change chemically?
A reaction occurs through the breaking of bonds and the formation of new bonds.
What are the classifications of chemical reactions?
Synthesis, decomposition, single replacement, double displacement, combustion, and polymerization
What does the Law of Conversation of mass tell us?
All chemical reactions must be balanced in terms of the number of atoms involved.
What does the formation of bonds release?
Energy
What does the breaking of bonds require?
Energy
What is a chemical reaction?
a process that rearranges the atoms in any substance(s) to produce one or more different substances; the process that creates chemical changes
What is a chemical equation?
an expression that describes the changes that happen in a chemical reaction, typically of the form reactants → products
What is a reactant?
a substance that is used or changed in a chemical reaction; the starting material or substance in a chemical reaction
What is a product?
a substance that is created or released in a chemical reaction
What do symbols represent?
The state of matter
Where to particles in a solid react?
At their surface
What does the greek letter Delta Δ indicate?
It indicates that heat is the catalyst in a chemical reaction.
What is aqueous (aq) mean?
Dissolved in water
What does insoluble mean?
not dissolvable in a particular solvent
What does soluble mean?
a substance that is able to dissolve in water.
What is the law of conservation of mass?
states that the total mass of reactants (starting materials) and the total mass of products (materials produced by the reaction) is the same
What does the term conservation mean?
Unchanged
What do symbols over the arrow in chemical reactions tell us?
They indicate when heat is added or a catalyst is used to speed up the reaction
What is an unbalanced chemical equation?
states that the total mass of reactants (starting materials) and the total mass of products (materials produced by the reaction) is the same
What is a balanced chemical equation?
a chemical equation that satisfies the law of conservation of mass, when the total numbers of atoms of each element are the same on both the reactant side and the product side of a chemical equation
What does the arrow in a chemical equation mean?
forms, produces, yields, etc.
What does the (g) symbol in a chemical equation mean?
the substance is a gas
What does the (l) symbol in a chemical equation mean?
The substance is a liquid
Translate this equation to words
Two moles of hydrogen gas plus a mole of oxygen gas yield two moles of liquid water.
Balance this reaction
What does the coefficient in a chemical equation represent?
The relative number of moles of each substance.
How do you balance a chemical equation?
To balance any chemical equation we adjust the coefficients until the same number of atoms appear on the reactant and product side of the equation.
What is a synthesis reaction?
a reaction in which two substances combine to form a third substance, also known as a combination reaction
What is a decomposition reaction?
a reaction in which a single substance breaks apart to form two or more new substances
What is an important decomposition reaction?
Electrolysis of water
Does a system of two carbon atoms have a lower energy when the atoms are bounded or when they are not bonded?
The carbon atoms have a lower energy when bonded
What is the average energy of different chemical bonds measured in?
kJ/mol
What does exothermic mean?
the products and reactants lose energy overall during the reaction.
What does indothermic mean?
Energy is absorbed by the system so the net change in enthalpy during the reaction is positive and ΔH has a positive sign.
What is electrolysis?
the result of a chemical reaction in an electrolytic cell
What does redox mean?
one substance or molecule is reduced and another oxidized
