4.11

Biofuels have certainly affected peoples everyday life. For instance, even though biofuels have increased food prices, expanded biofuel production will keep food prices higher in the future. This could be a problem on the poor because it would make it harder to get food and support their families. Some biofuels could reduce greenhouse gas emissions while replacing fossil fuels, but the effects of climate change depend on where and from what raw materials they are produced from. Certainly Biofuels have pros and cons to our society.

Ethanol and biodiesel currently claim only a small share of global final energy consumption. Biofuel productions have increased in recent years and is expected to continue increasing. We focus on biofuels because of their connection to gasoline and diesel fuels, important players because as liquids, they can be pumped of fuels vehicles and aircraft. The claims that biofuels produce significantly lower greenhouse gas emissions compared with fossil fuels were contested. Concerns were also raised over the competition that biofuels pose to food production. 

Ethan and biodiesel contribute to a net reduction of the greenhouse gas CO2. The fossil fuels are not carbon neutral, that is, the CO2 produced by their combustion is not offset by some natural process such as photosynthesis. Biodiesel has several inherent advantages over ethanol. Biodiesel bless well with existing diesel fuel and can be distributed via the same infrastructure. Like ethanol and because it contains oxygen, it burns more cleanly than diesel fuel releasing lower amounts of particulate matter. The sustainability of ethanol production is far more difficult to asses. Ethanol originates from several feedstocks, including corn, cane sugar, and sorghum.  I would use biodiesel in a car because it is better for the engine and it makes the gas milage better. Biodiesel or biofuel are better for our ecosystem because it lowers the amount of greenhouse gases in our atmosphere. Certainly, biofuel and biodiesel are going to become a major necessity for our future

4.10

The production of biodiesel has grown dramatically in recent years. Biodiesel is unique among transportation fuels in that it can be produced economically in small batches by individual consumers. Although biodiesel is made primarily from vegetable oils, animal fats work equally we’ll. Even though biodiesel could be synthesized from olive oil or butter, both are too expensive to use as a starting material. Instead, biodiesel is made from soy, rapeseed, or palm oil. It can also be produced from waste cooking oil, such as that used for french fries. Biodiesel is blended with petroleum-based diesel fuel, just like ethanol’s blended with gasoline. For example, B20 is 20% biodiesel and 80% diesel fuel. Blends up to 20% are fully compatible with any diesel engine, including those in medium- and heavy weight trucks.  Biodiesel is made from vegetable oils (palm oil, soybean oil) and animal fat. The difference between Biofuels and Biodiesel is that Biofuels are made from components other than petroleum derived products such as human and animal wastes, landfill gases, agricultural, and industrial wastes. On the other hand Biodiesel is made from vegetable oil and animal fat. 

4.9

Biofuels are a generic term for a renewable fuel derived from a biological source, such as trees, grasses, animals wastes, or agricultural crops. Like fossil fuels, all biofuels release CO2 when burned. However, Biofuels should release a lower net amount of CO2 into the atmosphere than fossil fuels. This is because the plants from which the biofuels originated absorbed CO2 from the atmosphere while they are growing. Whether burned as a fuel or not, these plants would release this same amount of CO2 back into biosphere. 

Enzymes are biological catalysts. Enzymes accelerate the chemical reaction. The molecules in the beginning of the process are called substrates and then later the Enzyme converts them into a different molecule. Most all metabolic processes in the cell need Enzymes in order to occur at rates fast enough to sustain life. 

Ethanol is an example of an alcohol, a hydrocarbon substituted with one or more OH groups bonded to its carbons atoms. One difference is that humans can safely consume small amounts of ethanol in wine, beer, and other alcoholic drinks. Most of the Ethanol produced in the United States comes from corn. Even though widely available in many parts of the world, wood is insufficient supply to meet our energy demands. So instead of relying on wood, people all sectors are eyeing liquid fuels like ethanol. Gasoline typically contained 10% of ethanol. Ethanol releases less energy because it contains oxygen. As a fuel, ethanol already is partially oxidized or burned. 

4.8

To understand the role of the catalyst, consider a typical exothermic reaction. In figure 4.20 the potential energy of the reactants  (left side) is higher than the potential energy of the products (right side) because it is an exothermic reaction. The green line indicates the energy changes during  reaction in the absence of a catalyst. Over all, this reaction gives off energy, but the energy initially increases because some bonds break first. The energy necessary to indicate a chemical reaction is called its activation energy and is indicated by the green arrow. Increasing the temperature often results in increased reactions rates. Increasing temperature isn’t a practical solution. The blue line shows how a catalyst can provide an alternative reaction pathway and thus a lower activation energy. This is the point at which the metal catalyst enters the reaction. The beauty of a catalyst is that it is not consumed and thus only small amounts of it must be used. Green chemists value catalytic reactions not only because small amounts of catalyst are employed, but also because the reaction often can be carried out at lower temperature.

4.5

Exothermic is a term applied to any chemical or physical change accompanied by the release of heat. Endothermic is a term applied to any chemical or physical change that absorbs energy A chemical reaction is endothermic when the potential energy of the products is higher than that of the reactants. In 4.13 part b you have to calculate the energy required lift one 1kg book the entire 2 m. Then you want to express this value in kilojoules and the value it to make the final calculation. Lastly to work off one donut it requires about lifting almost 90000 book. Temperature is a measure of the average kinetic energy of the atoms and or molecules present in a substance. Heat is the kinetic energy that flows from a hotter object to a colder one. There is always heat flowing through the human body. 

4.4

Distillation is a separation process in which a solution is heated to its boiling point reforming, and coking. To distill crude oil, first it must have to be pumped into a large vessel. As the temperature in the boiler increases, compounds with lower boiling points begin to vaporize. As the temperature further increases, compounds with higher boiling points vaporize. Once vaporized, all compounds travel up the distillation tower. Compounds are condensed to liquid at different heights in the tower due to a decrease in temperature with height. 

A. denoting or operated by a liquid moving in a confined space under pressure. Dynamite wouldn’t work because it would cause too much damage while fracturing shale hydraulically would do the opposite. 

B. A well consists of about 42 gallons of liquid and the ingredients are gasoline, diesel and home heating oil, jet fuel, heavy fuel oil, liquified refinery gas, and other products. 

C. i do not see where this is in the article 

4.3

Coal turned out to be a better energy source than wood because it yielded more heat per gram. Coal provided more than 50% of the nations energy until about 1940. By the 1960s coal was used for generating electricity. In figure 4.6 it displays the history of the US energy consumption.  Coal occurs in varying percentage of carbon and a lower percentage of oxygen. Generally the more oxygen a fuel contains, the less energy per gram it releases. Oxygen containing fuels lie lower on the potential energy scale. Although coal is available across the world and remains widely used fuel, it has serious drawbacks. A second drawback is the environmental harm caused by coal mining, Many streams rivers in Appalachia suffer from the effects of decades of mining operations. When coal deposits lie sufficiently close to the surface, mining techniques safer for miners are possible. A third drawback is that coal is a dirty fuel. A forth drawback may ultimately be the most serious, that burning coal produces carbon dioxide. Because of these drawbacks, and give that coal reserves are relatively plentiful in the US, significant research efforts are underway to develop new coal technologies. 

4.2

  1. Explain the energy transformation that cut in a neutrons cradle

As you can see from figure 4.5 it shows the motion of the metal balls swinging back and forth. When a ball is lifted it gives potential energy. Then the potential energy is converted into kinetic energy. After that the kinetic energy is gradually converted into potential energy as the ball rises and slows. Then the process repeats. 

  1. Why would a Newtons cradle not keep going forever

Newtons cradle would not keep going forever because the movement that is going back and forth would soon slow down and come to a stop. You realize the balls started to heat up because heat is transferred to the surrounding atoms and molecules in the air. As a result, when the balls come to a stop, the energy of the universe has been conserved.

  1. The calorie was introduced with the metric system in the late 18th century and was defined as the amount of heat necessary to raise the temperature of one gram of water by one degree Celsius. The joule is a unit of energy equal to 0.239 cal. One joule is approximately equal to the energy required to raise a 1kg book 10cm against the force of gravity.