1) On a phase diagram, the critical pressure is ________.
A) the pressure required to melt a solid
B) the pressure below which a substance is a solid at all temperatures
C) the pressure above which a substance is a liquid at all temperatures
D) the pressure at which a liquid changes to a gas
E) the pressure required to liquefy a gas at its critical temperature
2) The isomerization of methylisonitrile to acetonitrile
CH3NC (g) –> CH3CN (g)
is first order in CH3NC. The rate constant for the reaction is 9.45 x 10-5 s-1 at 478 K.
The half-life of the reaction when the initial [CH3NC] is 0.030 M is ________ s.
A) 1.06 x 104
B) 5.29 x 103
C) 3.53 x 105
D) 7.33 x 103
E) 1.36 x 10-4
3) There are ________ valence electrons in the Lewis structure of CH3OCH3.
A) 20
B) 16
C) 18
D) 24
E) 22
4) The formula weight of magnesium fluoride (MgF2), rounded to one decimal place, is
________ amu.
A) 86.6
B) 43.3
C) 62.3
D) 67.6
E) 92.9