Explanation:
<u>Hydrogen is used as fuel in automotives . It yields very high energy on combustion. It has great energy density by weight but poor energy density by volume. This is because Hydrogen is a very light gas, approx. 11 times lighter than normal air.</u> Hence it would require large volume of container to store it at normal atmospheric pressure conditions. That is why it is compressed using external energy to increase its density and decrease the volume needed for storage . So it becomes portable.
Only problem in this approach is that it utilities about 20% energy of the Hydrogen's energy potential to compress it . But this method proves cost effective as it reduces the overall weight of the container and also gives space to vehicles .
Answer: 19th century observers had noticed that the coastlines of North America and South America generally matched the coastlines of Europe and Africa. B. A German climatologist named Alfred Wegener proposed scientific evidence to support the idea that the continents once fit together.
Explanation:
This is a true statement!
For example, the biggest city in the Sahara (admittedly placed on the edge of it, on the Atlantic coast) is Nouakchott, the capital of Mauritania - it has 1 million people, so a great portion of the 2.5 million.
Another big city is Ghardaia in Algeria - of 100 000 people.
A. North Korea. They have so many problems that it keeps them from having economic prosperity.
