Carbon tetrachloride, CCl4 , is a solvent that was once used in large quantities in dry cleaning. Because it is a dense liquid that does not burn, it was also used in fire extinguishers. Unfortunately, its use was discontinued because it was found to be a carcinogen. It was manufactured by the following reaction: CS2 3Cl2 £ CCl4 S2Cl2 The reaction was economical because the byproduct disulfur dichloride, S2Cl2 , could be used by industry in the manufacture of rubber products and other materials. a. What is the percentage yield of CCl4 if 719 kg is produced from the reaction of 410. kg of CS2 . b. If 67.5 g of Cl2 are used in the reaction and 39.5 g of S2Cl2 is produced, what is the percentage yield? c. If the percentage yield of the industrial process is 83.3%, how many kilograms of CS2 should be reacted to obtain 5.00 104 kg of CCl4 ? How many kilograms of S2Cl2 will be produced, assuming the same yield for that product?

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.