Homework 8 Objective 5

Objective 5:

1. Boyle's law states that when the volume goes up the pressure goes down and vice versa.
2. When you go up in elevation the pressure decreases. This lower pressure would cause the balloon to expand and burst if it was filled all the way. This is why high-altitude balloons are only filled half way.
3. Pressure x volume= constant.
4. When you breathe in and flex your diaphram, you are increasing the volume of your lungs (by breathing in) and then you increase the pressure by flexing your diaphram.
5. As the diver goes deeper into the water, the pressure increases. According to Boyle's law, of the pressure increases, volume will decrease. This is important to the diver because the diver's body has numerous air spaces.

Citations:
http://wiki.answers.com/Q/Why_are_weather_balloons_partially_infated_before_they're_released_into_the_atmosphere
http://library.thinkquest.org/12596/boyles.html
http://wiki.answers.com/Q/How_does_Boyle%27s_law_apply_in_respiration
http://www.scubadivingsarasota.info/online-scuba-training/gas-laws

homework 8 objective 4

Homework 8

Objective 4

1. The particles at a warmer temperature are moving faster and that means there is more thermal energy. At a cooler temperature, the particles move slower and there is less energy.
2. The ice cream is suddenly exposed to warm air and then melts. It changes its state of matter. Ice cream is partly thin air, and this air makes up some of its volume. When you put the ice cream in hot air is starts to absorb it absorbs the heat.
3. When you add heat to something, the particles begin to vibrate a lot. When you cool it, the vibrating is less.
4. Condensation occurs when hot air and cold air come together.
5. Sublimation occurs when a solid can go from a solid to a gas. It is an endothermic reaction and absorbs heat.

Citations:
http://www.word-detective.com/howcome/icecreammelt.html
http://www.macmillan-caribbean.com/uploads/5c4bbec7-640b-4ff2-8fec-aad991ae2634_CSEC%20Chemistry%20pages.pdf

homework 8- objective 3

Homework 8

Objective 3

1. Chemical Energy because the atoms share electrons and give electrons so it is all changing. When you take all of the electrons off of something it turns into plasma.
2. A rolling bowling ball has kinetic energy.
3. A bowling ball that is still has potential energy.
4. Electromagnetic Energy is an occurrence of waves in matter. Electromagnetic energy is measured in waves.
5. Electrons moving from one place to another is electricity. An example is power outlets. The electrons come to the power outlet so we can plug things in. (cell phone chargers, etc.)

Citations:
http://griffinscience.com/
http://en.wikipedia.org/wiki/Electromagnetic_energy

Homework 8- Objective 2

Homework 8- Objective 2

1. The main difference between a chemical change and a physical change is that during a chemical change the identity of a substance’s chemical changes. During a physical change, the chemical nature of a substance doesn’t change.
2. The 4 ways a chemical change can happen are spontaneous, heat, light, and electricity.
3. The Law of Conservation is mass means that mass isn't created or destoyed. it is constant.
4. Temperature is a number that relates to energy, but it isn't energy. Thermal energy, or heat, is actual energy. Adding heat, means adding energy.
5. An endothermic reaction would be the reaction Zelle and I did in class. We put baking soda and acentric acid together, and it got cold. An exothermic reaction would be elephant toothpaste. The reaction became hot and you could feel the warmth on the container the experiment was done in. 

Citations:
http://en.wikipedia.org/wiki/Physical_change
http://en.wikipedia.org/wiki/Chemical_change#Examples_of_chemical_changes
http://en.wikipedia.org/wiki/Conservation_of_mass 
http://zonalandeducation.com/mstm/physics/mechanics/energy/heatAndTemperature/heatAndTemperature.html

Homework 8

Objective 1, November 2:

1. Mass is more useful to measure matter then weight because weight changes with where you are. Scientists don't want to get different answers so they use mass because it doesn't change.
2. The volume of the box is 619.65 centimeters cubed.
3. The most commonly used units for density are kilogram per cubic meter and the unit of gram per cubic centimeter.
4. The formula for density is mass divided by volume.
5. The formula for finding volume is length times width times height.
Citations:
http://en.wikipedia.org/wiki/Density#Formula_and_common_units
http://wiki.answers.com/Q/Why_is_mass_more_useful_than_weight_for_measuring_matter

Endothermic Reaction

Zelle and I did our reaction today. We made a video...but someone kindly deleted it for us! haha! O well...we will just explain it.


Our experiment called for 25ml of acetic acid and 15g of baking soda.... we didn't have that much acid, so we divided everything by 5 so we didn't have to use as much, but it was still balanced.  Since we didn't use as much ingredients as the experiment called for, our results weren't very dramatic, but it still worked.  The temperature went down 3-4 degrees Celsius.... and ended up being at about 18 degrees Celsius.


When we mixed everything together, we saw a few bubbles forming (a sign of a chemical reaction) and then it got colder.  Again, there would have been more bubbles if we used as much ingredients as the experiment called for.  Also, the acid smelled TERRIBLE!!!!!  You would have seen it on our video, but apparently someone thought theirs was better :)  hahaha.... just kidding!!!!

That is about it.... have a good weekend!!

Endothermic Reaction

Hey everybody!!  Zelle and I are doing endothermic reactions for Test 6.  We will have a video posted soon of our actual experiment and all of our materials and results. 


Endothermic: "within-heating" --> describes a process or reaction in which the system absorbs energy from the surroundings in the form of heat (takes in heat and doesn't produce it... so it is a cold reaction)


Materials

~ 25 ml of acetic acid
~15 g of baking soda
~ a styrofoam cup
~ a thermometer
~ stirring rod