Download Acid Basics

Acid Basics
Acids are compounds that give up hydrogen nuclei. What is a hydrogen nuclei? It’s a
proton. So acids give up protons. Recall that 99.9 % of all hydrogen (H) has no
neutrons in the nucleus and it’s just a proton. Here’s an example: HCl (hydrochloric
acid, the acid in your stomach that breaks down food) dissolves in water to give a cation
(H+) and an anion (Cl-). HCl → H+ + ClProtons are highly reactive (they want to bond!) and will combine with H2O molecules to
form H3O+. Notice that H3O+ (hydronium ion) has a positive charge because its charge is
out of balance. Compounds that accept protons are known as bases. Here’s that
reaction: H2O + H+ → H3O+
To sum up: acids give up protons and bases accept them.
Acids are rated on their strength, or ability to give up protons, on the pH scale. pH
stands for power of hydrogen and works like this: the pH scale goes from 1 (strongest
acid) to 14 (weakest acid) with 7 being neutral. Water is exactly 7. By the way, strong
acids are weak bases and vice versa.
Finally when we mix an acid and a base together a reaction occurs that gives a salt and
water. Salts are a large class of compounds that are defined as the product formed from
the neutralization of an acid and a base! Here’s an example:
HCl (acid) + NaOH (base) → NaCl (salt) + H2O (water!)
To which compound did the proton (H) go in the products? ______________
Answer the following questions
1. What is an acid?
2. What is a base?
3. What is the nucleus of 99.9% of all hydrogen atoms?
4. If an acid has a pH of 1 is it a strong or weak acid? Is it a strong or weak base?
5. What happens when you mix a acid and a base?
6. What is a salt?
Carbon: the Element of Life
Carbon is the basis of organic chemistry. Organic compounds (with some exceptions) are those
compounds that have carbon as a constituent atom of the compound. And organic compounds are
the key components of biochemistry, the chemistry of life as we know it.
What makes carbon so special that it has its own branch of chemistry and is so important for
living organisms? Recall that C has 4 valence electrons that can form strong covalent bonds
with other atoms including even stronger double and triple bonds. That’s important because
living things need to survive bumps and bruises in a tough environment. Carbon also makes a
tetrahedron pattern, think of a 4 sided pyramid, with C in the middle and its 4 covalent bonds at
the corners. This triangular faced structure is very strong as well as versatile. Carbon often
bonds with itself to form a variety of large structure molecules with ring, wall, and tube shapes,
perfect for building complex diverse morphologies (body structures) of living organisms. Finally,
many, if not most, organic molecules contain N, O and H atoms as well.
1. Look at the tetrahedron below and put the C nucleus in the center and the 4 valence electrons
at the corners.
2. Carbon makes ring structures. Every intersection of the lines below is a carbon atom.
Chemists don’t write the C’s since it would be time consuming and clutter the figure. Label all
the intersections with a C.
Answer the questions below:
1. What element is the basis of organic chemistry? What compounds are the basis of
biochemistry?
2. What are three types of covalent bonds C can make?
3. What is the shape of the carbon atom and its 4 covalent bonds? What kind of
structures can C make? Why is that important to living organisms?
4. What three other atoms are often bound to C in organic molecules?