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2.1 The Nature of Matter

Questions Answers

1. Name and describe the three subatomic particles that make up atoms. Proton: positive particle in the nucleus

Neutron: neutral particle in nucleus

Electron: negative particle that is much smaller in the electron cloud outside the nucleus.

2. a. The word “isotope”, in a way, just means a “type” of atom of a particular element. What is different about the different isotopes of any given element?
b. What does it mean for an atom to be “radioactive”? What do you think makes one isotope more radioactive than another?
  1. Isotopes are different because there are different amounts of neutrons in the nucleus.  
  2. A radioactive atom is really just an isotope.  The more neutrons in a type of element, the more unstable the atom will be, giving it more radioactivity.
3. Sulfuric acid is a compound with the formula H2SO4 . What does this formula tell you about the atomic makeup of this compound? (Check out this super cool periodic table if you aren’t sure which elements are being represented) Sulfuric acid is two Hydrogen, one Sulfur, and four Oxygen bonded together.
4. Describe the difference between a covalent bond and an ionic bond. Give an example of each A covalent bond is when two atoms share one or more electron to complete their electron shell.

An ionic bond is when a positive atom and a negative atom are attracted to each other by the forces of electronegativity.

2.2 Properties of Water

Questions Answers

1. What does it mean for a molecule to be polar? How does this lead to hydrogen bonding in water molecules? When a molecule is polar, it mean that one part is particularly negative, and one part is particularly positive.  When Hydrogen bonds with Oxygen, most of the electrons are towards Oxygen’s electron shell.
2. What is the difference between cohesion and adhesion? Give an example of each. Cohesion is when molecules are more attracted to other molecules of the same type, than another molecule.  Adhesion is when a molecule is more attracted to another molecule than it’s own kind of molecule.  An example of adhesion is when you put a wet piece of paper on a white board.  Cohesion is when you put a drop of water on plastic.  
3. Describe what a solution is in one sentence correctly using the following terms: solution, solute, solvent A solution is when a solute breaks down in a solvent.  The solvent is usually water.
4. Oil is nonpolar, meaning its molecules do not have the partial charges that polar water molecules have. Using polarity, explain why you think oil and water won’t mix. Oil and Water are not attracted to each other because they are opposites in a polarity way.
5. The values on a pH scale are not arbitrary or random. Explain the molecular relationship between a liquid with a pH of 4 and a liquid with a pH of 5. Which is the stronger acid? Liquid four is the stronger acid because it has a higher concentration of H+ ions.  
6. What is a buffer? Buffers are weak acids and bases that react with stronger acids and bases to prevent sharp changes in PH.


2.3 Carbon Compounds

Questions Answers

1. What are the five other elements that can bond with carbon to make up the molecules of life? Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur.
2. Carbon has more valence electrons (electrons available for bonding) than many other elements commonly found on Earth. Why does this make carbon so special and important? It makes it easy to bond with other atoms so it can form many different molecules needed for life on earth.
3. What is the relationship between monomers and polymers? Monomers are compound parts that join together to make polymers. They are both macromolecules.
4. For each macromolecule (carbohydrate, lipid, nucleic acid and protein) list the monomer and one major function in the body. Carbohydrate:Main source of food and sometimes used in structure.

Lipid:Store energy and can be used as a waterproof layer.

Nucleic acid:Store and transmit genetic info.

Protein:Regulate reactions, structure, and fight disease.

5. Explain the difference between plants and animals (humans) when it comes to storage of large amounts of excess sugar In plants they grow bigger and are more healthy when they heave more sugar.  In animals we convert it to fat and get less healthy so we have to burn it off.
6. How can you tell visually whether you are looking at a saturated or unsaturated fat? In unsaturated fat there is at least one carbon double bonded.  In saturated there is only one carbon double bonded.

Unsaturated fats tend to be liquid at room temperature.

7a. Look at the picture of the formation of a peptide bond at the bottom of page 48. Shown are two amino acids – alanine and serine. Name two structures that alanine and serine have in common, and one structural difference between them.
b. How does  your answer to question 7a explain why proteins are among the most diverse macromolecules?  
The both share the highlighted blue and green group.  Their differences are in the highlighted purple group.

They are among the most diverse because anything can be in the R group, and they can have tons of different properties.



2.4 Chemical Reactions and Enzymes

Questions Answers

1. Use the following words correctly in a sentence that describes what a chemical reaction is: chemical reaction, reactant, product A chemical reaction is when two reactants combine and chemically change to become a new thing, called a product.
2a. Explain the difference between an exothermic (energy-releasing) reaction and an endothermic (energy-absorbing) reaction.
b. All types of reactions have a specific activation energy. What is an activation energy?
Exothermic reactions are reactions when more energy than it took to make than reaction happen is released.   Endothermic reactions are reactions that happen when more energy is taken in then released.
Activation energy is the amount of energy it takes to start a reaction, since the amount of energy needs to be at a certain amount for them to take place.
3. How do catalysts speed up chemical reactions? Catalysts lower the activation energy making reactions more likely to happen.
4. Explain how an enzyme works using the following terms correctly: enzyme, substrate, active site, enzyme-substrate complex Enzymes have an active site that allows reactions to occur faster than normal.  A substrate is something that attaches to an active site to react.  Enzyme-substrates are the whole complex put together.
5. Lactase is an enzyme that breaks down lactose (the sugar in milk) into a form that the body can readily use. People who are lactose intolerant do not produce lactase, so they are unable to digest dairy products. The human body is capable of making tens of thousands of different enzymes, so why can’t lactose intolerant body systems just use a different enzyme to catalyze the reaction? Each enzyme is made of different things and they cannot be used to lower the activation energy of another thing properly.  (It would be like using a lawn mover for making a smoothie.)  Each enzyme is made specifically to do one job.
6. The enzyme amylase catalyzes the breakdown of carbohydrates into small disaccharides. This reaction occurs in the mouth and the small intestine, but not in the stomach. Why not? In the stomach there is hydrochloric acid which breaks down everything it touched.  If enzymes were down there, they could not live.  Nothing can live in the stomach.


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