6SA1 Hints

1.                 Sodium has 11 protons and 11 neutrons in its nucleus. Draw a sodium atom. Be sure to label the particles. Hint: The first energy level has ______ electrons, the second has ________, and the third has _____ electron.

2.                 Explain why carbon monoxide (CO) is or is not an element. H: Carbon monoxide is not an element because it has two different kinds of ________.

3.                 Explain Are all compounds mol­ecules? Why or why not? H: No; only compounds formed by __________ bonding are molecules.

4.                 Compare van derWaals forces, ionic bonds, and covalent bonds and how the number of electrons in an energy level affects bond formation.  H: Van der Waals forces hold __________ together. Ionic bonds are __________ attractions between two oppositely charged atoms. A covalent bond forms when electrons are ___________.

5.                 Explain how the number of electrons in an energy level affects bond formation? H: Atoms are most stable when there are a complete set of ____ electrons in the outer energy level (the ________ rule).

1.                 Beryllium has four protons in its nucleus. How many neutrons are in beryllium-9? Explain how you calculated your answer. ____ neutrons (Subtract  Be’s  atomic number from its mass); the number of protons added to the number of neutrons gives the atomic mass.

 

 

6SA2 Hints

1.   Identify the parts of this chemical reaction: A+B->AB. H: reactants on left, products on right.

2.   Diagram the energy changes that can take place in a chemical reaction. H: Diagrams should resemble Figures 6.15, 6.16, 6.17, which depict exothermic, endothermic, and catalyzed reactions.

3.   Explain why the number of atoms of reactants must equal the number of atoms of products formed. H: Matter is neither _________ nor __________; it can only change ________.

4. Describe the importance of enzymes to living organisms. H: Enzymes ________ the activation energy needed to start a chemical reaction.

5. For the fol­lowing chemical reaction, label the reactants and products, and then balance the chemical equation. _ H202 -» _ H20 + _ 02  H: Reactants on left, products on right – we did this one in class!

6. Draw a diagram of a roller coaster and write a paragraph relating the ride to activation energy and a chemical reaction. H: Roller coaster must be brought to the top of the structure before it can speed downhill; chemical reactions need sufficient activa­tion energy to begin.

 

6SA3 Hints

1. Water's ability to increase and decrease ________________ helps maintain pH.

2. As a polar molecule, electrons in hydrogen atom bonds are closer to the ____________ atom, creating a ___________ charge that attracts _________ atoms in solutes.

3. Check pH table: hydrochloric acid, ______ 7; sodium hydroxide, ______ 7; water, at __ (neutral).

4.  Solutions are ____________ mixtures (can’t separate as in salt water). Suspensions are ____________ mixtures (can separate as in salad dressing made out of oil and vinegar).

 

6SA4 Hints

1. no, because all known life-forms contain _________

2. Check table in text: ____________ store energy and provide support; lipids store energy, provide barriers; proteins transport substances, speed reactions, provide structural support, and make hormones; nucleic acids store and communicate genetic information.

3. Look at structure in text: ____________: C, H, 0; ____________: C, N, 0, H, S

4.  Protein properties stem from the _________ in which the amino acids assemble and determine how the peptides _______ into a three-dimensional structure.