Unit 4 A.5, A.7, and A.9

Electronegativity is the tendency of an atom to attract shared electrons within a chemical bond. A cohesive force is the attractive force between molecules in a substance. A mixture is the combination of materials that retain its separate identity. A heterogeneous mixture is a mixture that is not uniform throughout. A suspension is a mixture containing large dispersed solid particles that can be separated by filtration. The tyndall effect is the scattering of light caused by reflection from suspended particles. Colloid is a mixture containing small solid particles that does not settle out. Milk would be an example of a colloid. Homogeneous means uniform throughout. A solution is a homogeneous mixture of two or more substances. When mixing salt with water, the salt is the solute, the dissolved substance, and the water is the solvent, the dissolving agent. In the water cycle a repetitive process of rainfall, run-off, evaporation, and condensation occurs in the Earth's crust and atmosphere. Direct water use is water consumed by an end user and indirect water use is the water consumed in the preparation, production, or delivery of goods. The water found on the Earth's surface is called surface water and water from underground is called groundwater. An aquifer is a water-bearing layer of rock, sand, or gravel.

Unit 4 Sec. A and Sec. D Summary HW

7/23/14

Unit 4 Sec. A Summary HW

9)

10) Colloid because the mixture does not settle out.

13) a. 2.11%

b. 0.009%

14) Oceans, glaciers, rivers, and water vapor.

15) Water is a renewable source because it can be replenished by natural processes over time.  

16) Water constantly goes through a cycle and recycles all of the water so it can be possible that a dinosaur once swallowed the water.

Unit 4 Sec. D Summary HW

1) “Purify” water means processing the water making it clean.

2) Screenings, pre-chlorination, and flocculation.

3) Screening to prevent fish, sticks, and other large objects from entering the water, pre-chlorination which is adding chlorine to kill disease-causing organisms, and flocculation which is where crystals of aluminum added to remove suspended particles.

4) a. It would be difficult to remove the salt in the seawater because salt is soluble in water.

b. Distillation

5) 

6) Yes because the temperature in the water has increased causing global warming.

7) This quote means that the world is filled with water but very little of it is drinkable.

8) The water would not be recycled and fill up quickly.

11) Flocculation is when the crystals of aluminum hydroxide are added to remove suspended particles.

12) Calcium oxide is added to neutralize acidic water thus raising its pH to a proper level.

13) 1 ppm of fluoride is added to reduce tooth decay.

18) Chlorine kills disease-causing organisms making it cleaner.

19) Chlorine in water can react with organic compounds produced by decomposing animal and plant matter to form substances that can be harmful to human health.

Unit 3 D.1-D.2 and C.8-C.10

Cellular respiration is the process that is used by organisms to convert complex molecules into carbon dioxide and water molecules. A biomolecule is a large organic molecule found in living systems. A carbon cycle is the movement of carbon atoms within the Earth's ecosystems. In photosynthesis carbon dioxide goes in the plant, photosynthesis occurs, and oxygen gas and carbohydrates leave the plant. Global warming is the observed and predicted increases in average global surface temperatures.

Unit 3 Sec. D and Sec. C Summary HW

7/22/14

Unit 3 Sec. D Summary HW

1) Biomolecule is the large organic molecule found in living systems.

2) a. Natural gas

b. Coal

c. Petroleum

3) Coal, petroleum, and natural gas.

4) The sun.

5) People needed more ways for transportation, used petroleum for gas for the cars, allowed easier and faster transportation.

Unit 3 Sec. C Summary HW 3

17) a. Cellular respiration and as cutting timber are burned CO₂ is released into the atmosphere.

b. The lithosphere and atmosphere

c. Deforestation and fossil fuel emissions

18) Carbon enters the atmosphere through respiration, diffusion happens in the atmosphere into the hydrosphere, the lithosphere stores the carbon, and gets released into the atmosphere.  

19) CH₄ + 2 O₂ –––> CO₂ + 2 H₂O

20) a. As the water evaporates it gets even hotter.
b. Clouds can block the sun.

Unit 3 C.5

The equation for the burning of hydrocarbon is: Hydrocarbon + Oxygen gas –––> Carbon dioxide + Water + Thermal energy. After given the hydrocarbon, you plug in the formula of it to the equation. Then you have to balance the equation to make it work. The combustion of a hydrocarbon is a highly exothermic reaction.

Unit 3 Sec. C Summary HW 2

7/21/14

10)

11) a. C₅H₁₂ + 8 O₂ –––> 5 CO₂ + 6 H₂O + 3510 kJ

b. C₃H₈ + 5 O₂ –––> 3 CO₂ + 4 H₂O + 2200 kJ
c. 2 C₆H₁₄ + 19 O₂ –––> 12 CO₂ + 14 H₂O + 4141 kJ

Section C.3

1) a. It requires energy to break it apart.

b. Requires energy

c. It’s similar because it separates the product.

d. The chemical bonds attach to each other just like two magnets.

4) a. Exothermic because the burning fossil fuels releases energy.
b. The biomolecules of prehistoric plants and animals.

Unit 3 C.2-C.4

There are three different types of energy; there is potential, kinetic, and chemical energy. Potential energy is energy of position. Kinetic energy is energy related to motion. Chemical energy is a form of potential energy stored in chemical compounds. Thermal energy, also known as heat, is the energy a material posses due to its temperature. Endothermic is a process that requires the addition of energy and exothermic is a process that involves the release of energy. The law of conservation of energy states that energy is neither created nor destroyed in any mechanical, physical, or chemical processes. Heat of combustion is the amount of thermal energy released when a material burns. Molar heat of combustion is the amount of thermal energy released from burning one mole of a substance.

Unit 3 Sec. C Summary HW

7/20/14

1) The petroleum is sometimes considered “buried sunshine” because it stores energy.

2) a. Potential energy is energy of position and it is stored within a coiled spring.

b. Kinetic energy is energy related to motion and an example would be the movement of a car.

3) In a chemical reaction energy is released, bonds break, and reactant atoms reorganize to form new bonds.

4) A molecule of butane because it contains more electrons so it creates more energy.

5) a. Kinetic energy   

b. Potential energy

c. Kinetic energy

d. Potential energy

e. Kinetic energy

6) The law of conservation of energy states that energy is neither created nor destroyed in any mechanical, physical, or chemical processes.

7) Chemical bonds stores energy so it requires energy to break it.

8) a. Exothermic because the wood is releasing energy as it burns.  

b. Endothermic because it requires additional energy to crack the large hydrocarbon molecule.

c. Endothermic because it requires additional energy to digest the candy bar.

9) When burning a candle, the reactants release energy from the product.

Unit 3 B.1-B.4

A polymer is a molecule composed of very large numbers of identical repeating units and a monomer is a compound where the molecules react to form the repeating units of a polymer. In chemistry there is a branch called organic chemistry that deals with hydrocarbons. In hydrocarbon molecules, carbon atoms that are chemically linked to one another is called a carbon chain. In an atom the shell surrounds the atom's nucleus with one or more electrons. The first shell surrounding the nucleus has a capacity of two electrons and the second shell has the capacity to hold eight electrons. Every atom combines with another atom to get eight electrons in its shell. The electrons in the outer most shell are called valence electrons. A covalent bond is the sharing of two or more valence electrons between two atoms. The Lewis dot structures helps indicate covalent bonds. Another way to represent a covalent bond would be by drawing a line and this is called a structural formula. Petrochemicals are any organic compounds that are produced from petroleum or natural gas. An addition reaction is a reaction at the double or triple bond within an organic molecule and an addition polymer is a polymer that is formed by repeated addition reactions.

Unit 3 Sec. B Summary HW

7/17/14

1) A covalent bond is the sharing of two or more valence electrons between two atoms.

3) The elements share their electrons like two dogs tugging at the same sock so each element can have the 8 electrons it needs.

4) The dot in a Lewis dot structure represents an electron.

5) The dash will help identify which electrons are shared by the elements in a covalent bond.

21)    H     H    H

          |       |       |

H –– C –– C = C –– H

          |       |     |

         H     H    H

Unit 3 A.10-A.12

Extrapolation is the process of estimating a value based on known data points. Intermolecular forces are the result of uneven distribution of electrical charge in a molecule. A polar molecule is a molecule that has a partially positive and negative charge. When drawing the alkane molecules, two ways of drawing the molecules is either as a straight-chain alkane or as a branched-chain alkane. The straight-chain alkane is an alkane consisting of molecules where the carbon atoms are linked together side by side. The branched-chain alkane is when one carbon atom is linked to three or four other carbon atoms. Structural isomers are molecules that have the same molecular formulas but different arrangements of atoms.

Unit 3 Sec. A Summary HW 4

7/16/14

24) Methane (CH₄), pentane (C₅H₁₂), hexane (C₆H₁₄), and octane (C₈H₁₈). It’s ranked in this order because it’s in order of the alkane series.

25) a.

b. The branched-chain molecule because the molecules are more condensed.

26) a. A short, straight chain because it has less molecules.

b. A long, branched chain because it is more condensed.

c. A short, branched chain because it is more condensed. 

Section A.8

1) a. Table 3.3 is organized in alphabetical order.

b. No, because the boiling point and the molecular formula is not written in increasing order.

2) a. A more useful way would be by ordering the table in order of the total number of carbon atoms.  

b. The table would look like table 3.4 with the hydrocarbon names in the order: methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane.

3) Methane, ethane, propane, and butane.

4) The boiling point would be less than 22 degrees Celsius.

5) Pentane

6) The decane molecules are stronger with more carbon atoms than butane molecules.

Section A.9

6) Butane C₄H₁₀ Pentane C₅H₁₂

7) a. i. Heptane

ii. Nonane

b. C₇H₁₆ and C₉H₂₀

8) a. C₂₅H₅₂

b. The molecular formula because it is smaller and easier to write.