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I know this was kind of addressed in a question someone asked earlier but I just wanted to ask if we would be marked down if we left the stoichiometric coefficient as a fraction? I know different professors prefer different things so I just wanted to clarify to see if it would necessarily be seen as a mistake if we left the fraction instead of multiplying both sides to get rid of it?
In past chemistry classes, we have converted the fraction to a decimal and rounded to the correct number of sig figs. I assume Lavelle will prefer we do this since that is typically how figures are reported on lab reports and other experimental documents.
I would personally refrain from keeping fractions in the formula because of how easy of a fix it is. All you really have to do is multiply everything by the denominator to remove the fraction. It's an easy fix for something you won't have to worry about later.
Dr.Lavelle states it's better that the fractions are left in whole numbers when balancing equations. Since he prefers it that way, I think it is better to keep the habit of doing it often when it comes down to fractions in a chemical equation.
My best guess is just to turn the fractions into whole numbers just to be safe, because in the lecture the professor did mention that stoichiometric coefficients should not be fractions, but ultimately I think it just depends on if the question specifies otherwise.
I think in most cases we should always leave the Stoichiometric coefficients in integers, for example, in the butane combustion class example, professor Lavelle multiplied by all stoichiometric coefficients by 2 in order to have every coefficient as an integer. Unless the question specifically says "leave the stoichiometric coefficient in fraction form" (which I think is not very common), then we leave them in fractions.
Hope it helps!
Hope it helps!
KSong_1J wrote:I know this was kind of addressed in a question someone asked earlier but I just wanted to ask if we would be marked down if we left the stoichiometric coefficient as a fraction? I know different professors prefer different things so I just wanted to clarify to see if it would necessarily be seen as a mistake if we left the fraction instead of multiplying both sides to get rid of it?
I think it's a stated rule never to have fractions as stoichiometric coefficients when balancing chemical reactions! (Or it's highly recommended to put them as whole numbers)
I think it is fine to have a fraction as the coefficient. But it will be more convenient if the fractions are converted into whole numbers, especially when you need to do further calculations such as finding the molecular formula etc.
I think Professor Lavelle said in a previous lecture that chemists prefer coefficients to be integers instead of fractions. I know it seems bothersome to convert decimals and fractions into integers, but I think the safe bet is to convert them into integers.
I think it is always safe to convert the fractions into integers for the stoichiometric coefficients in a balanced equation. I remember there was this one multiple-choice question in the post-assessment modules for balancing equations, and the correct answer had stoichiometric coefficients with integers rather than with fractions.
I would definitely say to make all your stoichiometric coefficients into integers. I know Dr. Lavelle mentioned to do so in a lecture, and the UA who hosted tonight's Workshop also said to be sure to convert them into whole numbers, so I would put in that extra step just to be safe. You can always ask your TA to double check how they will be grading, though. :)
Whenever Dr. Lavelle has done these types of problems, he always makes sure that the final answer is an integer. In his module videos, he specifically showed that the last step in balancing an equation was to multiply by a factor to get an integer.
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