Hydrogen space shuttle

Stoichiometry has important practical applications, such as predicting how much product can be formed in a reaction. For example, in the space shuttle fuel cell, oxygen reacts with hydrogen to produce water, which is used for life support (Fig. L.l). Let s look at the calculation space shuttle engineers would have to do to find out how much water is formed when 0.25 mol 02 reacts with hydrogen gas. 

FIGURE L.l One of the three hydrogen-oxygen fuel cells used on the space shuttle to provide life-support electricity and drinking water. 

The problem was solved by Francis Bacon, a British scientist and engineer, who developed an idea proposed by Sir William Grove in 18.39. A fuel cell generates electricity directly from a chemical reaction, as in a battery, but uses reactants that are supplied continuously, as in an engine. A fuel cell that runs on hydrogen and oxygen is currently installed on the space shuttle (see Fig. L.l). An advantage of this fuel cell is that the only product of the cell reaction, water, can be used for life support. 

The hydrogen-oxygen cell used in the space shuttle is called an alkali fuel cell, because it has an alkaline electrolyte ... 

Fossil fuels are nonrenewable, and combustion products contaminate the atmosphere. Consequently, scientists are searching for new sources of energy. One possibility is molecular hydrogen, which releases energy when it reacts with oxygen 2 H2(g) + 02(g) 2H2 0(/) + Energy Hydrogen powers the rockets of the space shuttle,... 

After it has been separated, hydrogen is an unusually clean-energy carrier and clean enough for the U.S. space shuttle program to use hydrogen-powered fuel cells to operate the shuttle s electrical systems while the by-product of drinking water is used by the crew. 

Since liquid hydrogen has the greatest energy content per unit weight of any fuel, NASA used liquid hydrogen as the primary fuel for the Saturn 5 moon rockets and the Space Shuttle. 

The space shuttle uses a fuel cell as a source of energy. This cell depends on the oxidation of hydrogen by oxygen to form water. The fuel cell operates under basic conditions, so it is sometimes referred to as an alkaline fuel cell. Figure 11.31, on the next page, shows the design of the cell. The half-reactions and the overall reaction are as follows. 

Similarly, transporting, storing at the station, and pumping liquid hydrogen at 21K is an even more formidable task. Everyone knows it well what kind of safety precautions are undertaken when a space shuttle lifting main rocket is fuelled with liquid hydrogen and oxygen. 

FIGURE L.l One of the three hydrogen-oxygen fuel cells used on the space shuttle. Although only one cell is needed to provide life-support electricity and drinking water shuttle flight rules require that all three be functioning. In April 1987, a mission of space shuttle Columbia was cut short when one of the fuel cells malfunctioned. 

Liquid hydrogen has been used as a fuel in the U.S. space program for many years. Hydrogen powered the Saturn V rocket that carried the first astronauts to the moon, and it fuels the rocket engines of the space shuttle (Figure 14.14a). 

PROBLEM 14.19 The space shuttle fuel tank contains 1.45 X 106 L of liquid hydrogen, which has a density of 0.088 g/L. How much heat (in kilojoules) is liberated when the hydrogen burns in an excess of oxygen How many kilograms of oxygen are needed to oxidize the hydrogen ... 

Liquid hydrogen fuel powers the rockets of the U.S. space shuttle. 

NASA has long used liquid hydrogen to fuel space rockets. Now NASA also uses fuel cells within the space shuttle cabin to provide electrical power to the shuttle s instruments. The water that is created in the fuel cell is then used as drinking water by the crew. 

The main engines of the space shuttle burn hydrogen and oxygen, with water as the product. Is this synthetic (human-made) water the same as water found in nature Explain. 

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