Ch. 19 & 14ap nuclear chemistry & kinetics test [65 points] Honors Chemistry

Show your work in an organized manner, includes any relevant equation / formula, proper units in your work / answer, and the proper number of significant figures in your answer.

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Signature: ___________________________

 

1. Write the (hypothetical ?) nuclear reaction involving [15 points]

a. 35P undergoing positron emission: __________________________

b. the fission of 240Np --> 90Sr + ________

c. the alpha decay of 140Ba: ___________________________

 

2. What is the age of an object that currently contains 2.5 g 14C, which originally had 7.0 g 14C. The half-life of 14C is 5.73 * 103 years. [10 points]

 

3. In the combustion of ethane

C2H6 + O2 --> CO2 + H2O

the rate of the consumption of oxygen is 10.0 mM / second. [15 points]

a. what is the rate of consumption of ethane ?

b. what is the rate of appearance of carbon dioxide ?

c. what is the rate of the reaction ?

 

4. A chemical reaction consumes 45 kJ /mole of heat under constant pressure conditions, where the activation energy for the forward reaction (E a,f) is 35 kJ / mole. [10 points]

a. sketch the reaction energy profile, label E a,b ; E a,f ; ∆H; E reactant ; E product.

b. What is the activation energy of the backward reaction (E a,b) ?


4. What is the rate law (i.e. value of the exponents and rate constant, including its units) in the consumption of ethane (see # 3) based on the following (hypothetical ?) experimental data [15 points]

Expt

[C2H6] (M)

[O2] (M)

Rate (mM / s)

1

5.0

2.0

1.0

2

5.0

8.0

2.0

3

10.0

8.0

4.0