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1- The volume of a sample of gas is 650. mL at a pressure of 1.60 atm. Assume th

ID: 1007674 • Letter: 1

Question

1- The volume of a sample of gas is 650. mL at a pressure of 1.60 atm. Assume that the temperature is held constant.

a)What is the volume of the sample at a pressure of 2.00 atm?

B)What is the pressure of the sample when the volume is 500. mL?

2) What volume will 5.00 g of N2O gas occupy at 50C and 12.0 atm?

3) How many liters of O2 are required to prepare 5.0 L of HCN?

Half life problems: use the method At = A0e kt = A0e ( 0.693t t1/2 )

4) A sample of 35 16S, a emitter, has an activitiy of 0.100 µCi. In 20.0 days, the activity of the sample has declined to 0.0853 µCi. What is the half-life of 35 16S?

5) The half-life of 59 26Fe is 44.6 days. How long will it take for 95.0% of a sample of this nuclide to decay?

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Explanation / Answer

1.

a. P1V1 = P2V2

   (1.6*0.65 = 2*v2)

v2 = FINAL VOLUME = 0.52 L

b. (1.6*0.65 = P2*0.5)

P2 = 2.08 atm

2.

from ideal gas equation

PV = nRT

(12*V) = (5/44)*0.0821*323

v= volume of gas = 0.2511 L

3.

4. k = 1/tln(a/x)

   k = (1/20)ln(0.1/0.0853) = 0.00795 day-1

   t1/2 = 0.693/0.00795 = 87.17 days

5. k = 0.693/44.6 = 0.0155 day-1

    0.0155 = (1/t)ln(100/5)

   t = 193.27 days