An Introduction to Chemical Reactions and Equations (3.1.1) Flashcards
• Starting materials (reactants), finished materials (products) and special conditions describing chemical changes (reactions) are expressed in concise
statements called chemical equations.
• Starting materials (reactants), finished materials (products) and special conditions describing chemical changes (reactions) are expressed in concise
statements called chemical equations.
• Reactions obey the law of conservation of mass.
• Reactions obey the law of conservation of mass.
• Reactant atoms are balanced with product atoms using integer coefficients.
• Reactant atoms are balanced with product atoms using integer coefficients.
The plus sign (+) between reactants is read “reacts
with”, and the arrow is read “to produce”.
Stoichiometric coefficients are whole number
(integer) coefficients that indicate the number of
units of each reactant and product involved in a
balanced equation.
Subscripts are never changed to balance a
chemical equation.
Phases of matter (solid, liquid, gas, aqueous) give
information about the physical state of the materials
present as the reaction proceeds.
A reaction arrow separates reactants from products
and indicates the direction of the reaction.
In this example, addition of two molecules of
hydrogen gas to one molecule of oxygen gas
produces two units of liquid water.
Equations are similar to recipes, with each reactant
being an ingredient in the recipe. The reactants in
the pancake example are 2 eggs, 2 cups of flour,
and a cup of milk. This produces 12 pancakes. The
reaction arrow represents cooking.
In this example, iron reacts with oxygen to produce
iron(III) oxide, (Fe2O3). How much oxygen is used?.
The diatomic oxygen on the left must be balanced
with the 3 oxygen atoms on the right in the product.
A common multiple (6) is found between the
subscripts 2 and 3. Each substance is multiplied by
an appropriate coefficient. Finally, the iron atoms
are balanced by placing a 4 in front of the iron on
the reactant side. Now there are 4 atoms of iron and
6 atoms of oxygen on each side of the equation.
The equation is balanced.
The plus sign (+) between reactants is read “reacts
with”, and the arrow is read “to produce”.
Stoichiometric coefficients are whole number
(integer) coefficients that indicate the number of
units of each reactant and product involved in a
balanced equation.
Subscripts are never changed to balance a
chemical equation.
Phases of matter (solid, liquid, gas, aqueous) give
information about the physical state of the materials
present as the reaction proceeds.
A reaction arrow separates reactants from products
and indicates the direction of the reaction.
In this example, addition of two molecules of
hydrogen gas to one molecule of oxygen gas
produces two units of liquid water.
Equations are similar to recipes, with each reactant
being an ingredient in the recipe. The reactants in
the pancake example are 2 eggs, 2 cups of flour,
and a cup of milk. This produces 12 pancakes. The
reaction arrow represents cooking.
In this example, iron reacts with oxygen to produce
iron(III) oxide, (Fe2O3). How much oxygen is used?.
The diatomic oxygen on the left must be balanced
with the 3 oxygen atoms on the right in the product.
A common multiple (6) is found between the
subscripts 2 and 3. Each substance is multiplied by
an appropriate coefficient. Finally, the iron atoms
are balanced by placing a 4 in front of the iron on
the reactant side. Now there are 4 atoms of iron and
6 atoms of oxygen on each side of the equation.
The equation is balanced.
