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My report on "Chemical Reactions and Stoichiometry"
My report on "Chemical Reactions and Stoichiometry"
Student name: D-Rob
Teacher name: Ms. Chrisman
School: PPHS
Submission Time: 3/3/10 2:19 PM
Page 1 : http://mw2.concord.org/public/part2/chemreact/page1.cml
1. When does a chemical reaction occur? (Note: You can reset the model or even play it backwards .)
(a) Any two atoms can form a bond at any time.
(b) When two unbonded atoms collide with each other.
(c) When any two atoms hit each other even if they have already formed bonds to other atoms.
(d) Sometimes, when bonded atoms collide with something else, the bond breaks.
(e) Both B and D are correct.
My answer is (e) (1:59:47 PM)
2. If the atoms are heated to a high temperature:
(a) bonds tend to form rather than break.
(b) bonds tend to break rather than form.
(c) on average there are just as many atoms without bonds as atoms with bonds.
(d) the temperature seems to have no effect on bonding.
My answer is (b) (1:59:56 PM)
Page 2 : http://mw2.concord.org/public/part2/chemreact/page2.cml
1. How does the atom concentration affect the rate of the chemical reaction?
(a) Concentration has no effect.
(b) Increased concentration = increased reaction rate.
(c) Increased concentration = decreased reaction rate.
My answer is (b) (2:01:02 PM)
2. Explain the connection between concentration, collisions, and reaction rate.
As concentration increases so does the reactions rate and the amount of collisions. (2:01:37 PM)
Page 3 : http://mw2.concord.org/public/part2/chemreact/page3.cml
1. How does the temperature affect the rate of the chemical reaction?
(a) Temperature has no effect.
(b) Higher temperature = increased reaction rate.
(c) Higher temperature = decreased reaction rate.
My answer is (b) (2:02:53 PM)
2. Explain the connection between temperature, collisions, and reaction rate.
As temperature increases so does the reaction rate and the amount of collisions stays the same. (2:03:13 PM)
3. What do you think would happen if you could raise the temperature to a much higher level than is allowed using the slider above?
(a) It will just form bonds even faster.
(b) No bonds will form.
(c) Bonds will form, but they will also break apart.
My answer is (c) (2:03:22 PM)
Page 4 : http://mw2.concord.org/public/part2/chemreact/page4.cml
1. What changes did you make to the size of the container and the temperature to reach 80% completion the fastest way possible? Explain why that worked.
I increased the temperature because the higher the temperature is the more often reactions will form. (2:05:16 PM)
2. Why shouldn't you set the temperature for the highest possible value if your goal is to have about 80% of the atoms bonded to form molecules?
If the temperature is to high then the bonds will break almost as often as they form. (2:05:53 PM)
Page 5 : http://mw2.concord.org/public/part2/chemreact/page5.cml
1. Describe what happens in the following reaction: A + B2 AB + B
One molecule of B bonds with the molecule of A and the other molecule of B remains on it's own. (2:07:42 PM)
Page 6 : http://mw2.concord.org/public/part2/chemreact/page6.cml
1. Which hydrogen to chlorine ratios give a reaction that forms HCl with nothing left over? (Select all that work.)
(a) 1 hydrogen : 1 chlorine
(b) 2 hydrogen : 1 chlorine
(c) 2 hydrogen : 2 chlorine
(d) 2 hydrogen : 3 chlorine
(e) 4 hydrogen : 4 chlorine
My answer is NOT ANSWERED.
2. What is the correct balanced equation for making water from hydrogen and oxygen?
(a) H2 + O2 --> H2O
(b) 2 H2 + O2 --> H2O
(c) 4 H2 +2 O2 --> 4 H2O
(d) 2 H2 + O2 --> 2 H2O
(e) 2 H2 +2 O2 --> 4 H2O
(f) H2 +2 O2 --> H2O
My answer is (d) (2:10:37 PM)
Page 7 : http://mw2.concord.org/public/part2/chemreact/page7.cml
1. Which is the limiting reactant in the 2nd reaction?
(a) fuel
(b) oxygen
(c) both are limiting
My answer is (a) (2:11:27 PM)
2. Explain why it is hard to get ALL of the fuel to react if you use exactly the right ratio of fuel to oxygen. hint
Because some of the oxygen will bond with other oxygen atoms. (2:12:36 PM)
3. To power your car a specific amount of gasoline (fuel) is mixed with air (containing oxygen). If the mixture is not right, then your car will not have much power, or it will be spitting out lots of unburned fuel as a pollutant, or both. What do you think is the best fuel/oxygen mixture to optimize power and reduce pollution (i.e. get the most fuel in the cylinder which can be burned efficiently)?
(a) use the perfect ratio of fuel to oxygen as indicated by the chemical equation
(b) use extra fuel, making oxygen the limiting reactant
(c) use a lot of extra oxygen, making the fuel a very limiting reactant
(d) use a little extra oxygen, making the fuel the limiting reactant
My answer is (d) (2:12:57 PM)
Page 8 : http://mw2.concord.org/public/part2/chemreact/page8.cml
1. Reaction 1 is what type of reaction:
(a) synthesis
(b) decomposition
(c) single displacement
(d) double displacement
My answer is (b) (2:13:57 PM)
2. Reaction 2 is what type of reaction:
(a) synthesis
(b) decomposition
(c) single displacement
(d) double displacement
My answer is (a) (2:14:01 PM)
3. Reaction 3 is what type of reaction:
(a) synthesis
(b) decomposition
(c) single displacement
(d) double displacement
My answer is (c) (2:14:05 PM)
Page 9 : http://mw2.concord.org/public/part2/chemreact/page9.cml
1. Which of the following affect the rate of reaction?
(a) concentration of reactants
(b) temperature of reactants
(c) boiling point of reactants
(d) both A and B
(e) none of the above
My answer is (d) (2:15:02 PM)
2. Explain your answer for the previous question about factors affecting reaction rates.
As temperature and concentration increased the rate of the reaction is sped up. (2:15:30 PM)
3. The process by which food rots is ultimately driven by chemical reactions. Why does refrigerating food make the food last longer? (Be sure to explain it at the molecular level.)
Keeping the temperature down slows the rate at which reactions will occur. (2:17:20 PM)
4. Which chemical equation below is shorthand for the following description? One molecule of methane (CH4) reacts with two molecules of oxygen (O2) to form one molecule of carbon dioxide (CO2) and two molecules of water (H2O):
(a) CH4 + O2 --> CO2 + H2O
(b) 2 CH4 + 4 O2 --> 2 CO2 + 4 H2O
(c) CH4 + 2 O2 --> CO2 + 2 H2O
(d) CH4 + 2 O2 --> 2 CO2 + 2 H2O
My answer is (c) (2:18:09 PM)
5. Aluminum reacts with oxygen to form aluminum oxide, a thin non-reactive coating that prevents aluminum from further rusting. The UNBALANCED chemical equation is: Al + O2 Al2O3. What is the correct BALANCED chemical equation?
(a) 8 Al + 6 O2 --> 4 Al2O3
(b) 2 Al + 3 O2 --> Al2O3
(c) 4 Al + 3 O2 --> 2 Al2O3
My answer is (a) (2:18:46 PM)
6. Some dry powder fire extinguishers contain baking soda and use the following reaction to produce carbon dioxide (CO2), which helps to smother the fire: 2 NaHCO3 Na2CO3 + H2O + CO2. What type of reaction is this?
(a) synthesis
(b) decomposition
(c) single displacement
(d) double displacement
My answer is (b) (2:19:10 PM)
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