Give an example each of a desirable and an undesirable chemical change?

Chemical changes involve changes in chemical composition. A desirable chemical change is the conversion of carbon dioxide and water to glucose and oxygen, in presence of sunlight. This reaction is more commonly known as photosynthesis and is carried out by green plants (which contain the chlorophyll pigment). This reaction maintains the balances of gases in our atmosphere, provides us with food (directly or indirectly), is the source of fuels (either fresh such as wood, or fossilized, such as coal or petroleum) and generates oxygen for our sustenance. 

An undesirable chemical change is rusting of iron and steel. Exposure to atmospheric elements, such as moisture, causes the formation of ferric oxide, which results in weakening of metal components, loss of luster and electrical conductivity. Rusting results in economic losses around the world.

Hope this helps.  

What are three strong feelings that Bruno experiences in Chapter 3?

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How does a hot cup of tea lose heat ?

Thermodynamics is the field that studies energy transformations that occur in matter.

A cup of hot tea is actually an open system in which energy can be transferred from the hot tea to the surroundings. The molecules in the hot tea are moving faster than those in the surrounding environment and there will be a transfer of heat to the surroundings due to convection. If the tea is very hot, the air above it gains heat energy and the molecules move apart from each other causing them to become less dense and they rise. Eventually, as heat dissipates to the surroundings, the molecules of the atmospheric gases move closer together, become more dense and will sink. The process of convection occurs when matter is in the liquid or gaseous states.

Conduction will occur if someone places their hand on the hot tea cup. The higher temperature of the cup of hot tea will transfer heat by conduction to the cooler object--the person's hand when the faster moving molecules transfer energy to the slower moving molecules.

Therefore, both convection and conduction cause the hot tea to lose heat energy to the surrounding environment.

Did President Roosevelt know about Pearl Harbor before the attack?

If you are asking whether President Franklin D. Roosevelt knew that the Japanese were going to attack Pearl Harbor, the answer is no.  If you are asking whether Roosevelt knew that the Japanese were likely to attack American territory or interests somewhere at some time, the answer is yes.  However, there is a tremendous difference between these two levels of knowledge.  Reputable historians do not believe that FDR knew that a Japanese attack on Pearl Harbor was going to happen.

The idea that FDR did know about the attack is usually put forward by conspiracy theorists. They correctly assert that FDR wanted to get into WWII.  They also correctly assert that the US had intelligence that showed that Japan was planning to attack American territory or its allies.  However, they take these facts to mean that FDR actually knew that there was going to be an attack on Pearl Harbor itself and that he allowed that attack to happen to give the US an excuse to go to war.  Reputable historians reject this conclusion.

FDR had no way of knowing when or where the Japanese were going to attack.  There were many possible places they could have attacked.  Even though he knew that they wanted and intended to attack the US or its allies, he had no actual knowledge of which specific targets they might attack.  To think of this in modern terms, we know perfectly well that ISIS wants to attack America and its allies.  However, this does not mean that we have any idea where and when it will next try to attack.

Reputable historians do not believe that FDR had any real knowledge of where and when the Japanese would attack. Therefore, we have to say that he did not “know about Pearl Harbor before the attack.”

How did Prohibition help lead to the rise of organized crime?

The 18th amendment to the Constitution established prohibition in our country. It was now illegal to make, to transport, or to sell alcohol in our country. Most people said they believed the idea of Prohibition was a good one. However, their actions suggested they really didn’t agree with the concept.

Even though people agreed with the idea of Prohibition, they didn’t stop drinking. Secret clubs, called speakeasies, formed. Alcohol flowed freely in these speakeasies. Since the demand for alcohol didn’t disappear with Prohibition, there was a need to try to satisfy the demand. However since it was illegal to make, to transport, or to sell alcohol, organized crime syndicates got involved trying to satisfy the demand for alcohol. Since it was illegal to be involved in the alcohol trade and business, prices rose making this a very profitable industry, even though it was an illegal industry. Organized crime was willing to take the risk of making huge profits knowing there was a possibility of being prosecuted for doing this. As a result, organized crime became very active in satisfying the demand for alcohol during Prohibition.

What is a solute?

Solute is a substance that is dissolved into another substance (known as a solvent) to form solution. A common example of a solute is common salt (sodium chloride). When mixed in water (a solvent), we get salt water. Another commonly used solute (from our day to day life) is sugar, which is usually added in tea or milk or coffee. In general, the solute has lesser quantity in comparison to solvent (think of how much sugar do we add in a cup of tea, maybe a teaspoon full in 150-200 ml solvent). Solutes and solvent are, generally, different phases. For example, all the above mentioned examples have solid solutes in liquid solvent. However, we can also have liquid solute in liquid solvent (think about thinner solution in a bucket of paint). 

Hope this helps. 

Guard cells control the size of the opening of the......?

Guard cells control the size of the opening of stomata. By this function, guard cells control the exchange of gases (mainly carbon dioxide and oxygen) between the leaves and the atmosphere. Guard cells are present in pairs and are part of the epidermis of the plants. When a stoma has to be opened, guard cells sense the signal and start producing cytoplasmic solutions. This causes a reduction in cell water potential and results in an influx of water. This causes inflation of guard cells and the stoma opens. Stoma can be closed by reversing the influx of water, which causes the guard cells to become flaccid. By controlling the level of carbon dioxide and oxygen in the plant, the stomata regulate photosynthesis and by controlling the transpiration levels, stomata avoids too much water loss from the plant.

Hope this helps.  

As part of the employment process, Marlow visits an old doctor who works for the company. What measurements does the doctor take and why? How does...

The old doctor Marlow had to visit before he deployed used "a thing like calipers and got the dimensions back and front and every way, taking notes carefully." The man is a phrenologist; he believes that the brain is divided into different "organs," each of which govern various beliefs and emotions. The more developed any given "organ" of the brain, the greater a person's propensity in that area. Further, they believed that you could thus determine a person's psychological makeup by feeling for lumps on the skull and measuring the cranium in various ways. (This "science" is not considered as obsolete and silly as the idea that a person's health and personality are governed by "humours" in the body.)

Marlow is annoyed by the meeting, but not so much because of the measurements, but because of the doctor's questions and off-hand comments. For example, he asks him if there is any madness in Marlow's family, a question Marlow considers unnecessarily intrusive. 

Discuss how dramatic irony plays out in "Roman Fever." What is the full story that neither Mrs. Slade nor Mrs. Ansley knows? What prompts the two...

In Edith Wharton's "Roman Fever," the two women have secrets they've kept from each other for years. The dramatic irony is that the reader has access to each woman's inner thoughts, so we know that they are keeping secrets before the characters reveal it to each other. This dramatic irony amplifies the story's tension and makes the ending much more powerful.

The full story the women don't know is that Delphin did not write the letter Mrs. Ansley has held so dear all of those years; also, Mrs. Slade didn't know that her husband (then fiancé) actually met Mrs. Ansley at the Colosseum and she became pregnant with his child.

The women reveal this information to each other because they have kept it secret for so long and can't keep it in anymore. They are dying to say what they know and put the other in her place. So, the urge to tell comes from a place of pettiness and revenge.

What are the Olmecs famous for?

The Olmec (1200 BC-400 BC) were a Mesoamerican people in the Gulf region of Mexico that were the predecessors of the Mayan and Aztec cultures. They developed urban areas with sacred temples and government buildings. They are most famours for the massive colossal stone heads that they constructed. Archaeologists are not sure what the purpose of the monuments were but are in relative agreement that the political leaders are depicted. The uniqueness of the facial features of each monument has led them to that conclusion. The leaders are depicted with jaguar paws and warrior helmets.

The stone monuments are nearly twenty feet in height and are made of basalt, which was transported nearly a hundred miles. There have been seventeen colossal stone head monuments discovered to date.

How are Lennie and George different from other people on the farm?

Lennie and George share a firm and lasting friendship and this state of companionship sets them apart from the other men on the ranch. 

The job of being a ranch hand entails a considerable amount of movement for many of the men, forcing them to travel to find work. In addition to a rather solitary sensibility that functions almost as a (masculine) code of values, the prevailing conditions of farm work during the Great Depression in California presented in the book serve to isolate individuals from one another.

There is a notable lack of friendship -- lasting or otherwise -- among the men on the ranch. Slim is admired, but holds himself somewhat aloof. Candy is very nice and friendly, yet until George and Lennie arrived he seems to have had no actual friendships on the ranch.

Added to the isolation produced by migratory patterns and a stoic social code, there are also class and race differences that keep people divided. Curley has no friends in part because he tries to maintain a class-based distance between himself as a representative of ownership and men who labor on the ranch.

George and Lennie defy the odds and maintain a remarkable friendship. The fact of this friendship makes the pair different from the others on the ranch.  

"If them other guys gets in jail they can rot for all anybody give a damn. But not us.”

Lennie broke in. “But not us! An’ why? Because…because I got you to look after me, and you got me to look after you, and that’s why.” He laughed delightedly. “Go on now, George!”

The stability of this friendship may be partly responsible for helping George and Lennie forge a shared dream as well wherein they will have a stake in their own labor by taking ownership of a small farm of their own. 

George and Lennie are conscious of their special status as men with a social network, however meager it may appear to the reader. Others are equally aware of this difference in the pair and this awareness is noted throughout the novel by the boss, Candy, Slim and others. 

More than any other elements of their characters, it is the friendship shared by George and Lennie that makes them different from the others on the ranch.

What is the setting of the short story "Raymond's Run"?

“Raymond’s Run” is set in Harlem, New York.

The setting of the story is important.  This is the story of a young girl attending a May Day race.  We know that the story takes place in Harlem, a neighborhood in New York City in the late sixties.  In this story, the neighborhood comes to life.

So I’m strolling down Broadway breathing out and breathing in on counts of seven, which is my lucky number, and here comes Gretchen and her sidekicks: Mary Louise, who used to be a friend of mine when she first moved to Harlem…

Squeaky likes her neighborhood.  She enjoys practicing her running through the streets.  She is definitely at home.  Another example of the neighborhood atmosphere is the May Day celebration. This is a neighborhood event that takes place every year.  Some girls dress up for the maypole dance, but Squeaky prefers to run.  She has a reputation for being a runner, and a good one.

Then all the kids standing on the side pile on me, banging me on the back and slapping my head with their May Day programs, for I have won again and everybody on 151st Street can walk tall for another year.

Squeaky has a tough time with the neighborhood kids.  She does not make friends easily, partly because she has to take care of her mentally handicapped older brother, Raymond.  People often make fun of Raymond, and Squeaky has to defend him.  Running is an area where Squeaky can be proud of herself.  It is something she can get better at with effort.  In this story, she learns that it is possible to make friends when you share something you care about.  She makes friends with Gretchen because she also loves running.

A good story uses its setting almost like a character.  Harlem is a unique neighborhood rich in culture and African American tradition.  This story demonstrates that richness by creating a colorful cast of characters and an endearing plot.