Author Question: What is the physical process whereby atoms or molecules tend to move from an area of higher ... (Read 53 times)

a0266361136 · **on:** Jul 16, 2018

What is the physical process whereby atoms or molecules tend to move from an area of higher concentration or pressure to an area of lower concentration or pressure?

a. Sublimation
b. Melting
c. Diffusion
d. Capillary action

Question 2

What is the density of a mixture of 40 oxygen (O2) and 60 helium at STPD?

a. 0.34 g/L
b. 0.55 g/L
c. 0.68 g/L
d. 1.25 g/L

Swizqar · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: C
Diffusion is the process whereby molecules move from areas of high concentration to areas of lower concentration.

Answer to Question 2

ANS: C
For the density of a gas mixture to be calculated, the percentage or fraction of each gas in the mixture must be known. For example, to calculate the density of air at STPD, the following equation is used:
dwair = (FN2 gmw N2) + (FO2 gmw O2) 22.4 L
dwair = (0.79 28) + (0.21 32) 22.4 L
dwair = 1.29 g/L