Chemistry Chapter 6: Chemicals & Their Reactions Flashcards
chemical reaction
a process in which
substances interact, forming new substances with new properties
word equation
describing a
chemical reaction using the names of the reactants and products
chemical equation
describing
a chemical reaction using the chemical formulas of the reactants and products
reactants
Chemicals, present at the start of a chemical reaction, that is used up
during the reaction
products
Chemicals produced during a chemical reaction
scientific law
statement that summarizes an observed pattern in nature.
Law of conservation of mass
states that the total mass of the products in a chemical reaction is the same as the total mass of the reactants.
Skeleton Equation
chemical equation with all the correct reactants and products to describe a chemical reaction, but it may or may not be balanced (it may or may not obey the “Law of Conservation of Mass”).
synthesis reaction
a reaction in which
two reactants combine to make a larger or more complex product; general pattern: A + B → AB
decomposition reaction
a reaction where a large or more complex molecule breaks down to form two (or more) simpler products; general pattern: AB → A + B
combustion
the rapid reaction of a
substance with oxygen to produce oxides
and energy; burning
complete combustion
a combustion
reaction of hydrocarbons that uses all the
available fuel and produces only carbon
dioxide, water, and energy; occurs when
the supply of oxygen is plentiful
incomplete combustion
a combustion reaction of hydrocarbons that may produce carbon monoxide, carbon,
carbon dioxide, water, and energy;
occurs when the oxygen supply is limited
corrosion
the breakdown of a metal
resulting from reactions with chemicals
in its environment (slower than combustion)
Beneficial Corrosion
When corrosion protects the metal from further corrosion (giving a protective oxide layer).
Examples: Aluminum, copper, & zinc
Rust & Factors
Rust: reddish-brown flaky material produced when metals
containing iron corrode.
Causes: presence of oxygen, water, and electrolytes, along with acidity
and mechanical stress.
Ways of Protecting Against Corrosion
- Protective Coatings
- Using corrosion-resistant materials
- Galvanizing
Protective Coatings (Against Corrosion)
A simple way to prevent corrosion is to cover the metal with a rust-inhibiting
paint, chrome, or plastic coating. Once
the coating is chipped or scratched, corrosion is inevitable
Corrosion-Resistant Materials
Use materials that do not
rust (more corrosion-resistant metals or non-metals, like plastic). Stainless steel is an example, has chromium, carbon, nickel, and iron (less).
Galvanizing
Steel coated with a thin layer of zinc, forming a hard, insoluble oxide over it.
