The state (phase) of the compounds can be expressed in the chemical equation. This is done by placing the correct label on the right hand side of the formula. There are only four labels that can be used:
(g) for gaseous compounds
(l) for liquids
(s) for solid compounds
(aq) for an aqueous (water) solution
To show that heat is needed for a reaction, a Greek delta (
) is placed above the arrow.
You may remember from
Physical and chemical change that energy cannot be created or destroyed during a chemical reaction but it may change form. In an exothermic reaction,
H is less than zero and in an endothermic reaction,
H is greater than zero. This value is often written at the end of a chemical equation.
Solid zinc metal reacts with aqueous hydrochloric acid to form an aqueous solution of zinc chloride (
)and hydrogen gas. Write a balanced equation for this reaction.
The reactants are zinc (
) and hydrochloric acid (
). The products are zinc chloride (
) and hydrogen (
).
You will notice that the zinc atoms balance but the chlorine and hydrogen atoms don't. Since there are two chlorine atoms on the right and only one on the left, we will give
a coefficient of 2 so that there will be two chlorine atoms on each side of the equation.
When you look at the equation again, you will see that all the atoms are now balanced.
In the initial description, you were told that zinc was a metal, hydrochloric acid and zinc chloride were in aqueous solutions and hydrogen was a gas.
Balance the following equation:
In this example, the first two steps are not necessary because the reactants and products have already been given.
With a complex equation, it is always best to start with atoms that appear only once on each side i.e.
,
and
atoms. Since the
atoms already balance, we will start with
and
atoms. There are two
atoms on the right and one on the left. We will add a second
atom by giving
a coefficient of two. There are two
atoms on the left and one on the right. To balance the
atoms,
will be given a coefficient of two. The equation now looks as follows:
,
and
atoms balance, but
and
atoms do not. There are six
atoms and ten
atoms on the left, and five
atoms and eight
atoms on the right. We need to add one
atom and two
atoms on the right to balance the equation. This is done by adding another
molecule on the right hand side. We now need to check the equation again:
The equation is now balanced.
The following video explains some of the concepts of balancing chemical equations.
Khan academy video on balancing chemical equations
Questions & Answers
I'm interested in biological psychology and cognitive psychology
Communication is effective because it allows individuals to share ideas, thoughts, and information with others.
effective communication can lead to improved outcomes in various settings, including personal relationships, business environments, and educational settings. By communicating effectively, individuals can negotiate effectively, solve problems collaboratively, and work towards common goals.
it starts up serve and return practice/assessments.it helps find voice talking therapy also assessments through relaxed conversation.
miss
Every time someone flushes a toilet in the apartment building, the person begins to jumb back automatically after hearing the flush, before the water temperature changes. Identify the types of learning, if it is classical conditioning identify the NS, UCS, CS and CR. If it is operant conditioning, identify the type of consequence positive reinforcement, negative reinforcement or punishment
nature is an hereditary factor while nurture is an environmental factor which constitute an individual personality. so if an individual's parent has a deviant behavior and was also brought up in an deviant environment, observation of the behavior and the inborn trait we make the individual deviant.
Samuel
I am taking this course because I am hoping that I could somehow learn more about my chosen field of interest and due to the fact that being a PsyD really ignites my passion as an individual the more I hope to learn about developing and literally explore the complexity of my critical thinking skills
