Question

7-A gas mixture consists of N2, O2, and Ne, where the mole fraction of N2 is 0.50 and the mole fraction of Ne is 0.20 If the mixture is at STP in a 3.0 L container, how many molecules of O2 are present?

8-Calculate the density of Freon-12, CF2Cl2, at 37.0°C and 0.369 atm.

9-Determine the final temperature of a gold nugget (mass= 256 g) that starts at 378 K and loses 5.37 kJ of heat to snowbank when it is lost. The specific heat capacity of gold is 0.128J/gk.

Answer 1

first and second question can be solved by gas equation while the third question with the formula Q=mc(T2-T1) . where Q is heat energy , m is mass , c is specific heat capacity , T is temperature .

NN Total N Nwe Total N Siney 2 0.50 nNe z O. 20 2 2 2 L Volume 2 22-4 lb 1 mol we Know at STP moL 3.L 2 22.4 0-134 mol z Total numbA Z. 2 0.50A 013 4 0.06 NNe 20.20 X0. 134 z0.02t 10 N67 0.02 0.13 4- 2 0.04 2 O 04 0.134 0.21 2 2) Ginen z243t 31 2 300 k 2 3.C P20.369 atm 7, 2 d73 P 21atm /2? at STP U2 22-4 2 T2 Ti 22-4X 30 0 66. 7litre 2 243 X 0. 36q 2 2 2) Ginen m2 266 7m 537 X10 T z 5.37 K7 C0.128 1/7h T 2. 2. Me6T,-T) 163.88 ) 12541 K