Gas hydrogenations

In the microwave-assisted or hot-filament-assisted CVD of diamond, methane and hydrogen gases (CH ca 1—5% and 95—99%) are used. In... 

The indusU ial reaction using nitrogen and hydrogen gases... 

Group B Hydrogen, gases, or vapors of manufactured origin... 

The decomposition of dimethyl ether (CH3OCH3) to methane, carbon monoxide, and hydrogen gases is found to be first-order At 500°C, a 150.0-mg sample of dimethyl ether is reduced to 43.2 mg after three quarters of an hour. Calculate... 

The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113°C to 22.799°C. The calorimeter assembly is known to have a total heat capacity of 3.00 kJ-(°C). (a) Write a balanced equation for the reaction. 

Sodium hydroxide, NaOH, is a soft, waxy, white, corrosive solid that is sold commercially as lye. It is an important industrial chemical because it is an inexpensive starting material for the production of other sodium salts. The amount of electricity used to electrolyze brine to produce NaOH in the chloralkali process (Section 12.13) is second only to the amount used to extract aluminum from its ores. The process produces chlorine and hydrogen gases as well as aqueous socFinn hydroxide (Fig. 14.17). The net ionic equation for the reaction is... 

The nitrogen and hydrogen gases, in a 1 3 ratio, are passed over a heated iron catalyst at a temperature of 400°C and a pressure of about 200 atmospheres. 

As a simple proof that a complex-like structure forms on the surface of metals immersed in a mixture of nitrogen and hydrogen gases, try immersing a piece of red-hot bronze in an atmosphere of ammonia. The surface of the metal soon forms a tough, impervious layer of bronze-ammonia complex, which imparts a dark-brown colour to the metal. The brown complex reacts readily with moisture if the metal is iron and is impermanent, but the complex on bronze persists, thereby allowing the colour to remain. 

A heterogeneous catalyst is in a different phase or state of matter than the reactants. Most commonly, the catalyst is a solid and the reactants are liquids or gases. These catalysts provide a surface for the reaction. The reactant on the surface is more reactive than the free molecule. Many times these homogeneous catalysts are finely divided metals. Chemists use an iron catalyst in the Haber process, which converts nitrogen and hydrogen gases into ammonia. The automobile catalytic converter is another example. 

If the temperature of the reaction mixture is increased, the amount of heat increases and the equilibrium would shift to the left in order to consume the added heat. In doing so, the concentration of nitrogen and hydrogen gases would increase and the concentration of ammonia gas would decrease. 

Note that there are 4 mol of gas (1 of nitrogen and 3 of hydrogen) on the left side and 2 mol on the right. If the container is made smaller, the pressure will increase and the equilibrium will shift to the right because 4 mol would be converted to 2 mol. The concentrations of nitrogen and hydrogen gases would decrease, and the concentration of ammonia would increase. 

Fig. 4.1 outlines the Haber process to make ammonia. The reaction of nitrogen and hydrogen gases was first studied by Haber with Nemst and Bosch in the period 1904-1916. The two gases are adjusted to a 3 1 H2 N2 mixture and compressed to 2,000-10,000 psi (150-600 atm). The mixture is filtered to remove traces of oil, joined to recycled gases, and is fed to the reactor at 400-600°C. The reactor (Fig. 4.2) contains an iron oxide catalyst that reduces to a porous iron metal in the H2 N2 mixture. Ruthenium on... 

Figure 4.2 In the reactor for ammonia synthesis, nitrogen and hydrogen gases are used. (Courtesy of Solutia Inc., Luling, LA)...

Spongy platinum has, besides tho power of causing the ignition of oxygon and hydrogen gases, that of condensing vapors upon its surface and in its pores to a... 

When he was electrolysing water and he switched off the power supply, he noticed that a current still flowed but in the reverse direction. Subsequently, the process was explained in terms of the reactions at the electrodes surfaces of the oxygen and hydrogen gases which had been produced during the electrolysis. 

The percentage yield of ammonia indicates the percentage of the nitrogen and hydrogen gases that are actually changed into ammonia gas. 

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