What scientific concept do you need to know in order to solve this problem? Our tutors have indicated that to solve this problem you will need to apply the Percent Yield concept. You can view video lessons to learn Percent Yield. Or if you need more Percent Yield practice, you can also practice Percent Yield practice problems. Our tutors rated the difficulty of What is the percent yield for a reaction in which 28 g of Cu Our expert Chemistry tutor, Jules took 3 minutes and 12 seconds to solve this problem.
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Analytical Chemistry Video Lessons. Cell Biology Video Lessons. Genetics Video Lessons. Biochemistry Video Lessons. Question fe Chemistry Stoichiometry Limiting Reagent. Stefan V. May 12, Ernest Z. Here are the basic steps to solve a theoretical yield problem.
Use the molar mass of "Zn" to convert grams of "Zn" to moles of "Zn". Use the molar ratio from the balanced equation to convert moles of "Zn" to moles of "Cu". Use the molar mass of "Cu" to convert moles of "Cu" to grams of "Cu".
Related questions How do you determine how much of the excess reactant is left over? Note that the voltage for the silver ion reduction is not doubled even though the reduction half-reaction had to be doubled to balance the overall redox equation.
A substance which is capable of being reduced very easily is a strong oxidizing agent. Conversely, a substance which is capable of being oxidized very easily is a strong reducing agent. According to the standard cell potential table, fluorine F 2 is the strongest oxidizing agent. It will oxidize any substance below on the table. For example, fluorine will oxidize gold metal according to the following reaction.
Lithium metal Li is the strongest reducing agent. It is capable of reducing any substance above on the table. For example, lithium will reduce water according to this reaction. Using the Table above will allow you to predict whether reactions will occur or not. For example, nickel metal is capable of reducing copper II ions, but is not capable of reducing zinc ions.
Read the material at the link below and answer the questions at the end:. This battery consisted of alternating disks of zinc and silver with pieces of cardboard soaked in brine separating the disks.
He found that the intensity of the shock increased with the number of metal plates in the system. Devices with twenty plates produced a shock that was quite painful. Two variations on the basic voltaic cell are the dry cell and the lead storage battery. Many common batteries, such as those used in a flashlight or remote control, are voltaic dry cells. These batteries are called dry cells because the electrolyte is a paste. They are relatively inexpensive, but do not last a long time and are not rechargeable.
In the zinc-carbon dry cell, the anode is a zinc container, while the cathode is a carbon rod through the center of the cell. The half-reactions for this dry cell are:. Anode oxidation :.
Cathode reduction :. The paste prevents the contents of the dry cell from freely mixing, so a salt bridge is not needed. The carbon rod is a conductor only and does not undergo reduction. The voltage produced by a fresh dry cell is 1.
An alkaline battery is a variation on the zinc-carbon dry cell. The alkaline battery has no carbon rod and uses a paste of zinc metal and potassium hydroxide instead of a solid metal anode.
The cathode half-reaction is the same, but the anode half-reaction is different. Advantages of the alkaline battery are that it has a longer shelf life and the voltage does not decrease during use. A battery is a group of electrochemical cells combined together as a source of direct electric current at a constant voltage. Dry cells are not true batteries since they are only one cell. The lead storage battery is commonly used as the power source in cars and other vehicles.
It consists of six identical cells joined together, each of which has a lead anode and a cathode made of lead IV oxide PbO 2 packed on a metal plate. A lead storage battery, such as those used in cars, consists of six identical electrochemical cells and is rechargeable.
The cathode and anode are both immersed in an aqueous solution of sulfuric acid, which acts as the electrolyte. The cell reactions are:. Each cell in a lead storage battery produces 2 V, so a total of 12 V is generated by the entire battery. This is used to start a car or power other electrical systems. Unlike a dry cell, the lead storage battery is rechargeable. Note that the forward redox reaction generates solid lead II sulfate which slowly builds up on the plates. Additionally, the concentration of sulfuric acid decreases.
When the car is running normally, its generator recharges the battery by forcing the above reactions to run in the opposite, or nonspontaneous direction. This reaction regenerates the lead, lead IV oxide, and sulfuric acid needed for the battery to function properly.
Theoretically, a lead storage battery should last forever. Do we have heat yet? The hypothesis was that the fusion would produce more energy than was required to cause the process to occur. Their process involved the electrolysis of heavy water water molecules containing some deuterium instead of normal hydrogen on a palladium electrode.
The experiments could not be reproduced and their scientific reputations were pretty well shot. However, in more recent years, both industry and government researchers are taking another look at this process. The device illustrated above is part of a government project, and NASA is completing some studies on the topic as well. A voltaic cell uses a spontaneous redox reaction to generate an electric current.
It is also possible to do the opposite. When an external source of direct current is applied to an electrochemical cell, a reaction that is normally nonspontaneous can be made to proceed.
Electrolysis is the process in which electrical energy is used to cause a nonspontaneous chemical reaction to occur. Electrolysis is responsible for the appearance of many everyday objects such as gold-plated or silver-plated jewelry and chrome-plated car bumpers. An electrolytic cell is the apparatus used for carrying out an electrolysis reaction.
In an electrolytic cell, electric current is applied to provide a source of electrons for driving the reaction in a nonspontaneous direction. In a voltaic cell, the reaction goes in a direction that releases electrons spontaneously. In an electrolytic cell, the input of electrons from an external source forces the reaction to go in the opposite direction. This makes the zinc electrode the anode and the copper electrode the cathode.
When the same half-cells are connected to a battery via the external wire, the reaction is forced to run in the opposite direction. The zinc electrode is now the cathode and the copper electrode is the anode. The standard cell potential is negative, indicating a nonspontaneous reaction. The battery must be capable of delivering at least 1. Another difference between a voltaic cell and an electrolytic cell is the signs of the electrodes.
In a voltaic cell, the anode is negative and the cathode is positive. In an electrolytic cell, the anode is positive because it is connected to the positive terminal of the battery. The cathode is therefore negative.
Electrons still flow through the cell form the anode to the cathode. More energy from the sun? With fossil fuels becoming more expensive and less available, scientists are looking for other energy sources. Hydrogen has long been considered an ideal source, since it does not pollute when it burns. The problem has been finding ways to generate hydrogen economically.
One new approach that is being studied is photoelectrolysis — the generation of electricity using photovoltaic cells to split water molecules. This technique is still in the research stage, but appears to be a very promising source of power in the future. The electrolysis of water produces hydrogen and oxygen gases. The electrolytic cell consists of a pair of platinum electrodes immersed in water to which a small amount of an electrolyte such as H 2 SO 4 has been added.
The electrolyte is necessary because pure water will not carry enough charge due to the lack of ions. At the anode, water is oxidized to oxygen gas and hydrogen ions. At the cathode, water is reduced to hydrogen gas and hydroxide ions. In order to obtain the overall reaction, the reduction half-reaction was multiplied by two to equalize the electrons.
The hydrogen ion and hydroxide ions produced in each reaction combine to form water. The H 2 SO 4 is not consumed in the reaction. Apparatus for the production of hydrogen and oxygen gases by the electrolysis of water.
A big electric bill. Production of NaOH is an important industrial process. Three different methods are employed, all of which involve the use of electricity. When calculating the price of sodium hydroxide a company has to charge in order to make a profit, the cost of electricity has to be factored in. To make a metric ton of NaOH, between kWh kilowatt hours are required. Compare that with the power needed to run an average house. You could power a home for months with the same amount of electricity.
Molten liquid sodium chloride can be electrolyzed to produce sodium metal and chlorine gas. At the anode, liquid chloride ions are oxidized to chlorine gas. The reactions and cell potentials are shown below:.
The battery must supply over 4 volts to carry out this electrolysis. This reaction is a major source of production of chlorine gas and is the only way to obtain pure sodium metal.
Chlorine gas is widely used in cleaning, disinfecting, and in swimming pools. It may be logical to assume that the electrolysis of aqueous sodium chloride, called brine , would yield the same result through the same reactions as the process in molten NaCl.
However, the reduction reaction that occurs at the cathode does not produce sodium metal because the water is reduced instead. This is because the reduction potential for water is only This makes the reduction of water preferable because its reduction potential is less negative. Chlorine gas is still produced at the anode, just as in the electrolysis of molten NaCl.
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