Our aim is to investigate how much quicker Essay Example for Free

Our aim is to investigate how much quicker Essay Aim:- Our aim is to investigate how much quicker a reaction happens if the acid we uses strength goes up, and also to see if there is a pattern which could be carried on to higher strength acids. Background Science:- Chemical reactions play a very important part in our life, some even keep us alive (the process of our digestion system is a series of chemical reactions which convert food into chemicals which can be more easily used by our bodies), other circumstances where chemical reactions are used in our bodies that cut down the amount of acid in your stomach, there are also chemicals in washing powder for removing stains by using chemicals called enzymes which speed up the breakdown of the chemicals in stains. All chemical reactions happen at various speeds, such as chemicals in fireworks which react very fast, within seconds of the firework being lit the reaction is over. Slow chemical reactions could be such things as the ripening of cheese so it can mature over time. Some adhesives we use require two chemicals to be mixed depending on the amounts used it could make the glue harden quickly or slowly. Some reactions happen slowly whereas some happen very fast. The name in which we measure a speed of a reaction is called a Rate Of Reaction. It can be measured in two ways, either the rate in which one of the products is produced, one of the products that is produced is gas, you can measure gas in a syringe or in a upturned burette. Another method that can be used is recording mass of the reactant, (how much the mass has added to its weight of lost). The mass could be recorded every minute and could be written like this, 1. 0g/60secs. Variables:- We had four variables to choose from, Temperature, Concentration, Surface area/Pressure and Catalyst. If we were to use temperature we would measure how much quicker the reaction would go if the acid and calcium were heated together, but we would have to keep the temperature at a constant heat as it wouldnt be a fair test if the reactants were getting hotter and colder. If we were to use a catalyst it would be used to speed up the reaction, but this would be unfair because we wouldnt be able to measure how much extra speed is being put in by the catalyst. Or we could change the surface area of the reactant, this would give the acid more of a area to act on, to measure this we would have to weigh the calcium first then expose it to the acid for a certain time and then take it out and weigh it, making sure we use the same concentration of acid each time to make it a fair test. We decided to use Concentration, for this we would change the strength of concentration each time and take a volume of gas that is given off every ten seconds. From choosing the variable Concentration we can measure the rate of gas that is being given of, this could be useful because we could work out how much gas per minute is being given off, from that we can then predict how much gas is being given off for any time you need to find. Prediction:- I think that as the strength of the acid goes up the rate of reaction will go up. Collision Theory:- I think this will happen because the higher the strength of the solution the more particles there are in the solution, which means more collisions more frequently. The acid will hit the calcium carbonate, if there is enough energy in the acid the calcium and acid will react together to give off Carbon Dioxide. The more the particles collide the faster they react. I have made a predicted graph, showing what I think the graph will look like. I have drawn in the lines of best fit showing the steepness of the line. This diagram shows how the acid particles collide with the marble chip to give off a gas. Method:- Set up apparatus as shown above. 1. Measure out desired amount of marble chips. 2. Measure out desired amount of hydrochloric acid 0. 25 mole first, then when all experiments with 1 mole have been completed go onto 0. 5 mole then 1 mole then 1. 5 and finally 2 mole. 3. Fill up the water bowl. 4. Fill measuring cylinder with water up to 100 ml. 5. Holding hand over the top of the measuring cylinder quickly turn it upside down and place it under the water (as shown above). If the water comes out refill the cylinder and try again. 6. Place tube so one end is coming up in the cylinder under water. 7. Put the marbles in the chronicle flask. 8. Pour in the hydrochloric acid and quickly affix the top with the tube coming out of it into the chronicle flask. 9. Decide at what time you will measure how much gas is given off. We decided to take a reading every 10 seconds, we also decided to start taking the readings at 30 seconds. You measure how much gas is given off by the water dropping in the measuring cylinder. E. g. 10 mls given off in the first 30 seconds. 10. Take these readings for 100 seconds using a stop watch to be precise. I am going to take 3 repeats, I am doing 3 because I can get a fair average from these 3 results. From the averages I will plot a graph to compare the different strength acids. Analysis:- (Graphs). From my graphs I clearly show the variable of different strengths of acids. As I used higher strength acids, the time in which the gas was produced got much faster. As the acids get stronger the lines become more inline. Whereas the 0. 5 points were all over the place. From my results I can see that my prediction was correct I think that as the strength of the acid goes up the rate of reaction will go up. I could see that from my results the strength of acid went up and the speed it took to make the gas went down. This links to the collision theory, that is that as the strength of the acid went up there were more particles to collide on the marble, which meant that more gas was given of due to more particles in the small mixture. The higher the strength of acid the more accurate the results became, we can see this because the range bars get smaller as the strength of the acid gets stronger. From the predicted graph I can see a difference in the results graph. The 1 mole strength acid has taken longer than the 0. 5 mole acid to produce the gas. I will explain the possible reasons for this more in my evaluation. Evaluation:- The main difficulty we faced was with the 2 mole strength acid because it reacted so fast we barely had time to read the times precisely. This may have meant we had unfair results. The main anomalous results were the 1 mole results, because from the information we have (collision theory) it tells us that it is stronger than the 0. 5 mole which means it should be lower than on the graph than 0. 5. But it isnt. This may have been because the results were read wrong, the acid we used may have been slightly too strong or the marble chips we used may have been smaller which means it is easier for the acids to break down. To improve the accuracy we could use a burette, which are far more accurate than a measuring cylinder or a gas cylinder. Gas Syringe Burette Computer data collectors are a very accurate way of registering the time, also if you were to use a camera recorder so you could look back at it and pause it when it got to the times when you needed to record a time. The results would never be the same because sometimes the measurement of marble chips maybe slightly more or less, or the accuracy of reading the time would be slightly out etc. As I said earlier in my investigation the results seemed to become more reliable as the strength of acid went up. Although it should be less accurate to measure the time as the acid strength went up it seemed to be more accurate. James Lane 11N Rates Of Reaction Investigation.

How Students Choose ESL Writing Assessment Prompts :: Teaching Education Writing Essays

How Students Choose ESL Writing Assessment Prompts This article, reporting on the research done by Margo Glew and Charlene Polio of Michigan State University, examines writing assessment in a different way than most research on the topic. The goal of this research was to look into how an ESL student chooses prompts for a writing exam when offered a choice. Polio and Glew not only investigate how they choose, but how long it takes each student to choose and if they should even be given a choice at all. There are numerous suggestions through research that provide possible answers to the questions at hand. Some say students tend to choose shorter questions, or questions placed first or second on the list. This research was inconclusive however. Polio and Glew argue that â€Å"the primary reason for offering students a choice of prompts is the belief that students should be allowed to choose a prompt that will enable them to display their best writing† (37). This applies especially to ESL students who come from a much larger variety of backgrounds than to regular English students. However, â€Å"there is no evidence that when students choose a prompt, they choose one that allows them to display their best writing skills† (38). It is also pointed out though, that giving choices decreases reliability, adding to the already difficult process of fairly scoring written tests. Some even think that choosing wastes time. The researchers thought that looking at how the students chose a prompt might shed light on whether or not they should have a choice. They used 26 students and through testing, video taping and interviewing, they found that most students looked at all prompts before choosing and that 21 out of 26 students choose their topic in under two minutes. â€Å"The median time before students began writing was less than 60 seconds, with a range of 18 to 182 seconds.† (42). Out of all 26 students, only one student started writing with one prompt and started over with a second. Through the interviews they discovered that 22 students chose a prompt based on â€Å"perceived familiarity or background knowledge.† Proving true that having a choice should increase their ability to display their best writing proving false the idea that having a choice is a waste of time.

A Poison Apple Essay

In the poem ‘ A Poison Apple ‘, poet William Blake illustrates that how a person, angry with another. Through a variety of tropological element, Blake paints a picture of the angst of one individual directed toward his friend. First he uses hyperbole to emphasis the effect he has created. This is evident when he writes that his tears are causing the anger to grow between him and his friend. As written on line five and line six of stanza two, ‘And I watered it in fears Night and morning with my tears, ’. In reality, tears do not make things grow. In the poem though, Blake’s despair is growing more and more with each and very tear he sheds. The hyperbole continue with ‘ I told my wrath, my wrath did end. ’ and ‘ I told it not, my wrath did grow. ’ Wrath is something inside a person that cannot be grow like a tree. It is an emotion that people cannot always control. In the poem, Blake is showing that he can control it but in reality he cannot. That was the start of the anger to his friend. Last but not least, the way he grows the tree is a strong hyperbole to the way people do normally. ‘ And I sunned it with smiles ‘ and ‘ And with soft deceitful wiles. in line seven and line eight of stanza two, it described the way the author grow his anger and wrath. Trees should be grown in mud but Blake’s ‘ tree ’ was bombastically grown in soft deceitful wiles which is impossible to happen in real life. The anger of him was becoming more and more. William Blake does a masterful job of comparing the growth of a tree in garden to the growth in life. Unfortunately the tree that Blake is growing is a â€Å" poison tree †. If thrives on the anger and wrath of a friend, rather than on the love that should be considered. Most things grow better with love.

The Greatest Generation Of The World War II Essay

Many of the Greatest Generations’ core values have been challenged by later generations due to changes in the economy, politics, war, social equality, technology, and the family structure. The Greatest Generation, a name that journalist Tom Brokaw popularized, refers to the generation that grew up during the Great Depression, served during World War II, and then worked hard and prospered after the War. The Greatest Generation believed in following rules and not questioning authority, focusing on the nuclear family, being patriotic, working hard, saving money and owning a house. These tenets have evolved during the last fifty years for better and for worse. The traditional values of the Greatest Generation taught them to respect law and order, follow the rules, and be patriotic. That generation did not question the reasons behind fighting in World War II. During that time, Americans sacrificed everything, from sugar to death of loved ones, all in the name of patriotism and America being the greatest power in the World. Supporting America’s war went from becoming a duty to optional in later generations. Observing the casualties of war and questioning the reason for entering war, later generations challenged the United States’ military presence in Vietnam, Iraq, and Afghanistan. The Greatest Generation also did not challenge racism, as the Baby Boomers did that were born after World War II. 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