Which of the following material phases cannot form a solution?
A) solids
B) liquids
C) gases
D) All of the above can form solutions.
E) None of the above can form solutions.
Answer: D
You might also like to view...
An automotive catalytic convertor is a packed bed in which a platinum catalyst is coated on the surface of small alumina spheres. A metal container holds the catalyst pellets and allows engine exhaust gases to flow through the bed of pellets. The catalyst must be heated by the exhaust gases to 300°C before the catalyst helps combust unburned hydrocarbons in the gases. The time required to achieve this temperature is critical because unburned hydrocarbons emitted by the vehicle during a cold start comprise a large fraction of the total emissions from the vehicle during an emission test. A fixed volume of catalyst is required but the shape of the bed can be modified to increase the heat-up rate. Compare the heat-up time for a bed 5-cm-diameter and 20-cm-long with one 10 cm diameter and
5-cm-long. The catalyst pellets are spherical, 5-mm-diameter, have a density of 2 g/cm3, thermal conductivity of 12 W/(m K) and specific heat of 1100 J/(kg K). The packed-bed void fraction is 0.5. Exhaust gas from the engine is at a temperature of 400°C, a flow rate of 6.4 gm/s, and has the properties of air.
GIVEN
FIND
The heat-up time (t) for the pellet surface temperature (Tp) to reach 300°C
ASSUMPTIONS
The initial temperature of the bed (To) = 20°C
SKETCH
In the past, most of the landmass on Earth was concentrated in a single, large continent
Indicate whether the statement is true or false
If a star has a parallax of 0.05", then its distance in light years is about:
A) 6.4 light years. B) 12.7 light years. C) 20 light years. D) 65 light years. E) 100 light years.
A bucket of water with total mass 23 kg is attached to a rope, which in turn is wound around a 0.050-m radius cylinder at the top of a well. The bucket is raised to the top of the well and released. The bucket is moving with a speed of 6.0 m/s upon hitting the water surface in the well. What is the angular speed of the cylinder at this instant?
a. 39 rad/s c. 120 rad/s b. 79 rad/s d. 160 rad/s