Homework Due 11-11-10

Objective 1:

1. Mass is more useful than weight when measuring matter because the weight of an object changes according to where it is. The mass of an object never changes, which makes it a better choice to measure matter.
2. The volume of this plastic box would be 619.65cm cubed.
3. The unit of measurement for density is g/cm cubed.
4. The formula for density is p = m/v. 
5. The formula for finding volume is length times width times height.

Objective 2:

1) The main difference between a chemical change and a physical change is the a chemical change isn’t reversible, while a physical change is. For example a physical change would be water freezing into ice...this you can reverse, and change the ice back into water. A chemical change would be wood burning into ash and carbon dioxide is produced. This you cannot undo because there is no way that you can make ash turn back into wood.

2) One type of chemical reaction is combustion. A combustion reaction is when oxygen combines with another compound to form water and carbon dioxide. This reaction is exothermic, which means that the reaction produces heat. Another type of chemical reaction is synthesis. A synthesis reaction is when two or more simple compounds combine to form a more complicated compound. A third type of chemical reaction is decomposition. A decomposition reaction is when a complex molecule breaks down to make simpler molecules. This is the complete opposite of a synthesis reaction. One other type of chemical reaction is acid-base. An acid-base reaction takes place when an acid and base react with each other. 

3) The Law of Conservation of Mass states that mass can change form, but it cannot be created or destroyed. This makes the mass of the reactants equal to the mass of the products. The person who created the Law of Conservation of Mass was formulated by Antoine Lavoisier in 1789, but Mikhail Lomonosov had previously expressed the same ideas in 1748 and tested and proved them in experiments. 

4) Temperature is the average measure of the energy in a substance. Thermal energy is the energy of an object due to the random motion of its atoms and molecules and substances.

5) An example of an exothermic reaction is wood burning. An example of an endothermic reaction is the evaporation of water. 

Objective 3:

1) Some forms of energy that are related to changes in matter are thermal energy, chemical energy, electromagnetic energy, and electrical energy.

2) A rolling bowling ball has kinetic energy.

3) A bowling ball sitting still has potential energy. 

4) Electromagnetic energy is the energy that comes from electromagnetic radiation. This radiation is made of waves, like radio waves and visible light. 

5) The energy of electrons moving from one place to another is electric energy. An example of this is lightning in the sky.

Objective 4: 

1) The thermal energy of particles that are at a warmer temperature would be greater than the thermal energy of particles that are at a lower temperature.

2) Ice cream melts on a warm sunny day because the thermal energy being produced by the sun makes a colder substance (in this case ice cream) melt. 

3) The melting point of particles has to do with vibrating particles because particles start vibrating faster and faster as they get warmer and warmer. So as the substance is being heated up to its melting point, the particles keep vibrating faster and faster.

4) Condensation occurs when the temperature of the air is the same as the dew point temperature. 

5) Sublimation results under the conditions where the temperature and pressure is below a substances triple point. 

Objective 5:

1) An inverse relationship is described by Boyle’s Law.

2) The formula for Boyle’s Law is pV = k... where p = the pressure of the system, v = volume of the gas, and k = a constant value that represents the product of the pressure and the volume of the system.

3) Boyle’s Law applies to physicians because the lungs are affected by Boyle’s Law while the doctor is listening to the lungs of a child. 

1. Boyle’s Law applies to SCUBA diving because there is a significant change in the pressure of the water as the diver goes deeper and deeper. As the pressure of the surrounding water increases, the diver is required to use more air from their tank.