CHEM102 Lecture Notes - Lecture 2: Reaction Rate, Enthalpy, Chemical Kinetics

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emeraldfly513

8 Feb 2018

School

University of Alberta

Department

Chemistry

Course

CHEM102

Professor

Sai Yiu

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CHEM102 Full Course Notes

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Chem 102 lecture 2 wednesday, january 10, 2018. It has to do with thermodynamics, or thermochemistry. Enthalpy change, or delta h, can be gotten from the difference between the energy at the beginning and at the end. Enthalpy change varies depending on the type of reaction and which direction the reaction is going in. Thermodynamics energy change and the extent (chemical equilibrium) Chemical kinetics concerns reaction rates of chemical reactions. It provides information of chemical reactions in the molecular world. 2 no2 (g) 2 no (g) + o2 (g) at 300 c: concentration of no2 decreases with time (not linear, concentration of o2 increases with time, concentration of no increases. Change in amount (or concentration of substance a) Concentration of a at t2 concentration of a at t1. Concentration decreases as time is increased (indicated by minus sign) (please take a look at the scanned file for this lecture) The instantaneous rate is reaction rate at a specific time.

Related Questions

1.Which of the following is a physical property?

A) ozone reacts with silver to give silver oxide

B) platinum metal does not react with hydrochloric acid

C) the density of lead

E) Sulfur burns in oxygen to form sulfur trioxide

2. Which of the following is a chemical property of gold?

A) is malleable

B) does not react with hydrochloric acid

C) is a good conductor of heat

D) is a good conductor of electricity

3) Which of the following is a physical change?

a) the freezing of water to form ice

B) the inability of gold react with water

C) the burning of paper

D) the sodium metal vigorously with water

E) the reaction of zinc with hydrochloric acid

4. Which one of the following would be classified as a heterogenous mixture?

A) copper nitrate solution

B) mix of table salt and black pepper

C) Salt water

D)brass

E) a sugar solution

5. Which of the following is a chemical change?

A) the boiling of water to form steam

B) crushing of lump of sulfur into yellow powder

C) the reaction of chlorine gas and sodium to form salt

E) hammering zinc into a thin film

6) An extensive property is

A) independent of the quantity of matter observed

B) difficult to measure

C) always strongly dependent on the external conditions

D) dependent on the quantity of matter observed

E) is a unique value regardless of the measurement conditions

7) Which of the following defines or expresses the concepts of accuracy?

A) average of the data

B) differences between the accepted answer and the average value of the data

C) deviation of the average

D) the closest value to the expected answer

E) reproducibility of a measurement

8) Hydrates are:

A) orgainc compounds that contain oxygen together with usual carbon and hydrogen

B) readily soluble in water and release energy

C) concentrated solutions of salts in water

D) moistyre sensitive hygroscopic inorganic salts

E) compounds in which each formula unit has one or more water molecules associated with it

9) Which of the following is the correct defintion of isomer?

A) Isomers are molecules with the same empirical formula but have different isotopes

B) Isomers are molecules that have the same molecular formula but contain different istotopes.

C) Isomers are molecules that have the same molecular formula but different arrangement of atoms in space

D) Isomers are molecules that have the same arrangements of atoms in space but different empirical and molecular formulas

E) Isomes are molecules that have the same empirical formula but different arrangements of atoms in space

10) Most water-soluble compounds of Group 1A or 2A elements are:

A) nonelectrolytes

B) weak electrolyes

C) weak acid

D) strong electrolytes

E) strong acids

11) to precipitate Cd2+(aq) from solution one could add:

A) KI(Aq)

B) NaCl(aq)

C) H2S(aq)

D)HNO3(aq)

E) HCl(aq)

12) Select a statement that best describe the oxidation process

A) in the oxidation process all elements experience an increase in oxidation state

B) in the oxidation process all elements change oxidation state

C) in the oxidation process some elements change their oxidation state

D) in the oxidation process some elements experience oxidation state increase

E) In the oxidation process only oxygen increases its oxidation state.

13. A disproportionation reaction is one in which:

A) the dame substance is oxidized and reduced

B) the equation is not balanced

C) both reactants are reduced

D) water must be added

C) more of one substance reacts than another

14) The energy of molecules of a gas:

A) is the same for all molecules at constant temperture

B) is dependent on concentration

C) increases with an increase in pressure

D) is distributed over a wide rande at constant temperature

E) increase with a decrease in temperture

15. The volume correction term in the van der Waals equation is present because:

A) molecules occupy volume

B) molecules attract each other

C) barometers are inaccurate

D) molecules repel each other

E) molecules are diatomic

I need help getting the chemical equations in part 4

Factors Affecting the Rates of Chemical Reactions 25-5 4. The Influence of Temperature the test tube with the evolved gas. The gas coming (a) Measure 5 mL of solution A (used in part over first wl contain some air that was present in into a test tube. Measure 4 mL of water and mL flask. After 2-3 min, test the gas in the Erlen of 3% H2O2 into a second test tube. Place both test meyer flask by inserting a glowing splint into the tubes in a 250-mL beaker of warm water (50Â°C). flask. Does the gas support combustion? what is the After about 3 min H202 solution into a 50-mL beaker, stir, and note the time. When the blue color appears, note and only the H202 solution to the flask. Continuously record the elapsed time. Compare the reacton swirl the contents of the flask. Does the gas evolve time with that observed for the second reaction more slowly? After a few minutes' wait, you should be mixture you studied in part 1 pou r solution A and then the identity of the gas? Rinse the flask and repeat the experiment, adding able to tell whether the CuCl2 catalyzes the reaction. Now fill another test tube with water and place it (b) Ignition Temperature. Review the Safety Pre over the gas delivery tube. Remove the stopper just cautions. In a fume hood, place 10 to 20 drops of methanol in a 30-mL beaker. Remove the beaker to your lab bench. Heat the end of a glass stirring rod at the tip of the inner blue cone of a Bunsen burner until the glass starts to soften. Quickly drop of 3 M CuCl, and 1 drop of 3 M FeCl, in that touch the heated end to the methanol. A chemical reaction should begin; if it does not, reheat the swirl the solution in the flask, and record the time rod and try again. Stay at arm length from the required to fill a 13 x 100 mm test tube with gas. beaker Do not touch the beaker until it has cooled long enough to add 2 drops of 3 M FeCl. Insert the stopper and continuously swirl the solution. Note and Rinse the flask. Add to it 20 mL of 3% H2O2, 1 order. Quickly replace the stopper, continuously record the time required to fill the test tube with gas Repeat the procedure using 20 mL of 3% H2O2 Describe the reaction that takes place. Write a ba5 anced chemical equation for the reaction. Why doesn't methanol burst into flames at room tem- drops of 3 M CuC, and 5 drops of 3 M FeC Quickly stopper the flask and continuously swirl the contents of the flask. Note and record the time required to fill a 13 Ã 100 mm test tube with gas. exposed to air? (c) Obtain a small square of cotton cloth (muslin) and a book of matches. (The cotton cloth should be tightly woven, about 2 to 3 cm on a side, and cleanly cut, so there are no ragged edges.) Work- ing in a hood, place about 10 mL of 50:50 (vv) 2-propanol-water in a 50- or 100-m beaker. Using crucible tongs, grasp the square by one corner and dip it into the 2 propanol-water solu tion. Lift the cloth and allow the excess solution to drain until no more solution drips off the cot ton-Place a small watch glass over the solution in the beaker. Carry the cotton, still held in the tongs, to your lab bench. Have a lab partner light a match and bring it just near enough to the square of cotton (held in the tongs) to ignite the 2 propanol-soaked cotton. Make certain that no other person is within arm's length of the flaming cloth. When the flame dies out, carefully note the condition of the cloth. How can the 2-propanol 6. The Importance of Mixing Reactants (a) Half-fill two 13 Ã 100 mm test tubes with water. Drop a small crystal of solid KMno, into each tube. Put one tube aside in a test tube rack or beaker and let it remain undisturbed. Swirl the second tube to dissolve the crystal of KMnO Observe the crystal in the undisturbed tube every few minutes, noting how long it takes for the crystal to dissolve and then to spread (diffuse. Record your observations. (b) Add 10 mL of 0.50 M H2C204 (oxalic acid) to 10 mL of 6 M H2S04 and mix thoroughly. Place 8 mL of this solution into each of two 15 x 125 mm test tubes. Measure out two separate 8 ml por tions of 0.005 M KMno. Add one portion of KMno, solution to one of the test tubes contain- ing oxalic acid, holding the test tube at a 45 angle and carefully pouring the KMnO, down the side of the test tube to avoid mixing the two solu- tions. Note the time. Pour another 8 mL of KMno4 into the second test tube, stopper the tube, mix by inverting the tube several times, and note the time. As the reactions proceed, Mno will oxi- dize the oxalic acid to CO, and will itself be reduced to colorless Mn2+ ion. Record the times required for the solutions in the two test tubes to become completely colorless burn without igniting the cotton? S. Effect of Catalysts on the Rate of Decomposi- tion of HOz Using the same apparatus as in part 3a, place 20 mL of 3% H2O2 in the flask. Fill a 13 Ã 100 mm test tube with water and invert it over the gas delivery tube. Then add 20 drops of 3 M CuCh to the flask, replace the stopper, continuously swirl the contents, and note and record how long it takes to fill

CHEM102 Lecture Notes - Lecture 2: Reaction Rate, Enthalpy, Chemical Kinetics

CHEM102 Full Course Notes

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