LS test

1. Water (H2O) is:

• A homogeneous mixture of H2 and O2
• A heterogeneous mixture of H2 and O2
• A pure substance
• An element

2. Air in Paris is:

• A homogeneous mixture
• A heterogeneous mixture
• A pure substance
• An element

3. Crude oil is predominantly a mixture of straight and branched chain aliphatic hydrocarbons, ranging from gaseous methance to viscous tar-like compounds with up to 80 carbons. Thus, crude oil is

• A homogeneous mixture
• A heterogeneous mixture
• A pure substance
• An element

4. Which of following statements is/are not correct?

• Solid always has a fixed volume

• Liquid has a fixed volume

• Liquid takes the volume of its container

• Gas can be compressed to a smaller volume or expanded to a larger volume.

5. Hydrogen is considered to be a promissing energy carier (a clean fuel). It is in the gas phase at the ambient conditions (room temperature and atmospheric pressure). To liquidify H2 (transform it into liquid), one can:

• Reduce pressure
• Increase pressure
• Reduce temperature
• Reduce pressure and reduce temperature

6. Currently, the global energy consumption keeps increased. To deal with this problem, one could propose:

• Invent a new source of energy
• Harvest the energy(ies) which is(are) already available to the human being
• Do nothing simply because we can not do anything. Consumption of energy is natural
• Let’s go back to before the industrial revolution, namely do not use any machine

7. Burning gasoline to power a car is a:

• Chemical – to – motion energy conversion process

• Efficient energy conversion with conversion yeild of 100%

• Endothermic process

• Exothermic process

8. Dissolving O2 into water is a:

• Chemical process
• Physical process
• Biological process
• Magical process

9. In some circumstance, having dissolved O2 in water is not desirable. One proposes to bubbling an inert gas into water to remove the dissolved O2. What could be the best innert gas for this purpose?

• N2
• CO2
• Ar
• H2

10. H2 produced by reforming natural gas contains CO impurity which is harmful to Pt catalyst in the proton exchange membrance fuel cell (e.g. Toyota H2 car). Please suggest a strategy to eliminate CO impurity from H2 gas.

• Use a nanoporous filter made of Pt
• Use a nanoporous filter made of Co
• Burn the mixture with O2
• Flux the mixture through a Ca(OH)2 solution