First:
the coefficients give the number of molecules (or atoms) involved in the reaction
. In the example reaction, two molecules of hydrogen react with one molecule of oxygen and produce two molecules of water. Second: the coefficients give the number of moles of each substance involved in the reaction.
What are the 3 characteristics of a chemical equation?
- the equation must represent known facts (all reactants and products must be identified)
- the equation must contain the correct formulas for the reactants and products (remember oxidation states to correctly write formulas and the diatomic molecules)
What are the coefficients in a balanced chemical equation?
The numbers placed in front of formulas to balance equations are called coefficients, and
they multiply all the atoms in a formula
. Thus, the symbol “2 NaHCO3” indicates two units of sodium bicarbonate, which contain 2 Na atoms, 2 H atoms, 2 C atoms, and 6 O atoms (2 X 3= 6, the coefficient times the subscript for O).
What 3 things does a balanced chemical equation show you?
A Balanced Equation
When a chemical equation is balanced, it is clear what
substances are the reactants, which are the products, how much of each substance is involved, as well as their relationship to each other
, and the steps that occur during the reaction.
How do you add coefficients to a balanced equation?
When you balance a chemical equation, you change coefficients. You never change subscripts. A coefficient is a whole number multiplier. To balance a chemical equation, you add these whole number multipliers (coefficients) to
make sure that there are the same number of atoms on each side of the arrow
.
Is it possible to have a coefficient of 0 in any chemical equations?
The
stoichiometric coefficient of any species that does not participate in a given chemical
reaction is zero.
What is an example of a color change?
Sometimes a change in color is simply
the mixing of two colors
and not due to a change in the composition of the substances used. For example, putting red food coloring and blue food coloring in a beaker of water results in purple water, but no chemical reaction has occurred.
How do you read chemical symbols?
In a chemical equation, the
reactants are written on the left
, and the products are written on the right. The coefficients next to the symbols of entities indicate the number of moles of a substance produced or used in the chemical reaction.
What are the rules for writing chemical equations?
A chemical equation should be
written with the reactants
(if there are two or more should be separated by ‘+’ symbol, same applicable to products) on the left side of an arrow and the products of the chemical reaction on the right side of the equation.
What is shown in a balanced chemical equation?
A balanced equation is an equation for a chemical reaction in which
the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products
. In other words, the mass and the charge are balanced on both sides of the reaction.
How do you interpret a balanced chemical equation?
-In the balanced chemical equation, the reactants are written on the left side of the chemical reaction and the products are written on the right side of the reaction. -From the balanced chemical equations we can interpret as follows: –
Relative masses of the reactants and products
.
What Cannot happen in a chemical reaction?
In a chemical reaction, the atoms and molecules produced by the reaction are called products. In a chemical reaction, only the atoms present in the reactants can end up in the products.
No new atoms are created
, and no atoms are destroyed.
What must never be changed in order to balance an equation?
The number of atoms of each element on both sides of the equation must be equal because matter cannot be created or destroyed. When balancing equations, the only numbers that can be changed are coefficients.
Subscripts in
a chemical formula cannot be changed to balance an equation.
How do you write a balanced chemical equation?
You cannot change subscripts in a chemical formula to balance a chemical equation; you can change only the
coefficients
. Changing subscripts changes the ratios of atoms in the molecule and the resulting chemical properties. For example, water (H
2
O) and hydrogen peroxide (H
2
O
2
) are chemically distinct substances.
What is the first thing you need for stoichiometry?
Just two things to remember before we get started: the first step in any stoichiometric problem is to always ensure that
the chemical reaction you are dealing with is balanced
, clarity of the concept of a ‘mole’ and the relationship between ‘amount (grams)’ and ‘moles’.
