Chemistry+Answer+Key

D10 ANSWERS PERFORMANCE QUESTIONS 2010

1. What charge does an Al ion have if it has only 10 electrons? 2. Which column of elements in the periodic table is most stable and least reactive? What are these elements called? **They are called noble gases and they are located in the last column.** 3. Which element in this group would be the **least likely** to react with other elements? a. Boron b. Carbon d. Oxygen 4. What element has 14 protons? 5. How many valence electrons does Sulfur have? 6. How many shells does Boron have electrons occupying space? How do you know based on the periodic table?
 * +3**
 * c. Neon**
 * Silicon**
 * 6 valence electrons**
 * Boron has 2 shells with electrons occupying space. I know this because it is in the second row on the periodic table, which indicates it is the second shell.**

D11

1. What is the name of the bond between a metal and a non-metal? 2. What kind of bond is formed in the creation of water?
 * An ionic bond.**
 * A covalent bond.**

D12

1. How can you tell if a substance is an acid or a base? 2. 2Na + 2H2O à 2NaOH + H2 is an example of what kind of reaction? 3. What end of the ph scale would vinegar most likely be close to? Include the number and property.
 * You can use the pH scale and see what number it is. If the number is closer to 1, then it is an acid. If the number is closer to 14, then the substance is a base.**
 * A Single replacement.**
 * Vinegar would be towards 1 on the ph scale, indicating it is an acid.**

D14

1. What are the byproducts of the combustion of a hydrocarbon? 2. What is a combustion reaction? 3. Complete the following combustion reaction C10H8 + 12 O2 ---> **10 CO2 + 4 H2O**
 * Carbon dioxide and water vapor**
 * Combu stion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. **

D15

1. What is a polymer? 2. What are some examples of synthetic polymers?
 * Any of a class of natural or synthetic substances composed of macromolecules that are multiples of monomers The monomers do not all need to be the same or have the same structure.**
 * Synthetic organic polymers include many plastics, including polyethylene, the nylons, polyurethanes, polyesters, vinyls (e.g., PVC), and synthetic rubbers.**

D16

1. Draw a diagram of a a. linear polymer b. branched polymer c. cross-linked polymer 2. What is a polymer made up of?
 * It is made up of monomers.**

D18

1.What is a long-term effect of landfills on the enviornment?
 * Landfills can effect the envoirnment long term with air pollution, contamination of surface waters, changes in landscape (accompanied by “visual discomfort”), and changes in soil fertility.**