F= 9/5 (C + 32)
C= 5/9 (F - 32 )
You have probably used these two equations often in chemistry class to convert from Celsius-to-Fahrenheit and the other way around, but did your teacher ever explain to you why these equations worked?
On the Celsius scale, the range of temperature between the Normal Melting Point of Ice and the Normal Boiling Point of Water is divided into 100 equal units. Whereas on the Fahrenheit scale, the range of temperature between the Normal Melting Point of Ice and the Normal Boiling Point of Water is divided into 180 equal units. *You can see both of these for yourself by subtracting the Boiling Point by the Melting Point on each scale.
*On the Celsius scale, zero is the melting point, and it corresponds to 32 degrees Fahrenheit.
* And the Fahrenheit degree is 5/9 of one Celsius degree. Why?
The 5/9 on the Celsius equation is obtained by dividing 100 ( Units between the Boiling Point and Melting Point of water [Celsius]) by 180 (Units between the Boiling Point and Melting Point of water[Fahrenheit]).
100/180 = 10/18 = 5/9
* Note that 0 Celsius corresponds to 32 Fahrenheit, so to convert Fahrenheit to Celsius you would have to subtract 32 degrees.
Breaking this equation down:
C= 5/9 ( F - 32 )
You can convert the Fahrenheit scale to the Celsius scale by using their ratio, then you must subtract 32 degrees. The equation could also be written like this:
C= 100/180 ( F - 32)
*The earlier equation is only a simplified version of the above equation.
Remember, the 5/9 is there because a Fahrenheit degree is 5/9 of a Celsius degree; by having that fraction present, you are acknowledging the relationship between a Fahrenheit degree and a Celsius degree, and thereby converting the units.
Dihydrogen Monoxide is dangerous!
In an attempt to show how readily junk science is taken to heart, a student at Eagle Rock Junior High won first prize at the Greater Idaho Falls Science Fair, by displaying false information about the common molecule in order to prove how gullible people really can be. In case you were wondering what dihydrogen monoxide is… It’s just water!
But the student shared false information with the viewers, such as:
- it can cause excessive sweating and vomiting
- it is a major component in acid rain
- it can cause severe burns in its gaseous state
- accidental inhalation can kill you
- it contributes to erosion
- it decreases effectiveness of automobile brakes
- it has been found in tumors of terminal cancer patients
When he then asked them whether or not dihydrogen monoxide should be controlled, forty-three said yes, six were undecided, and only one person knew that the chemical was water. When asked, most of the participants had wanted to BAN the chemical, to ban water. Clearly his science fair project was a success!
Accuracy is how close a value is to the true value.
Precision is how close values are to each other.
A real life example of accuracy is when you hit a bulls-eye, or when you get the correct answer on a test. It’s being right on, what the answer is and not close to it.
A real life example of precision is when you aim and throw something, if you are able to throw another thing in the same area as the first thing then you are precise.It’s the act of the next answer being close in range of the first.
This person is accurate.
This person is precise.
Here’s a real life scenario: You are an engineer and you are asked by your employer to make estimate just how much it is going to cost to create a building on an area of land. You have to consider how much the materials will cost, if the soil is stable or if it isn’t and just how much it will cost to dig a hole and possibly cement that area, you also have to consider the pay of your workers if you hired any. Other factors you have to consider may be human error, you never know if something is going to go wrong, if you or your workers forgot something- and that will cost additional money. Creating a new building can be unpredictable, so your estimate will have precision- it will have a range of one number to another number- of about what it will cost; in this scenario you can not be accurate.
A lot of real life scenarios are going to be precise, and not accurate due to external factors, because you never know what will happen.
However you can be accurate on what you will pay your workers, but time is a dependent variable so if something goes wrong with the construction your workers will have to fix it and you will have to pay your workers more than you anticipated.
Nasa’s last rover Curiosity is landing on Mars, August 5th 1:23 AM (Eastern). There will be LIVE FOOTAGE (well, you know, live as they can get 23 minutes later) hosted on Nasa’s site. ( http://mars.jpl.nasa.gov/msl/participate/ )
I don’t know about you guys, but that makes me awfully excited. >u<
Oh my God, I CANT WAIT 8 DAYS.
The other problems are set up exactly the same as this one, except for different mL of NaOH. I hope that this helps you to understand.
You have to get the new molarities first, which you can do with the starting mL and starting molarities given to you by getting the moles of each; and then you can get the new molarities by dividing the moles by the new volume of the total solution.
Then you need to get the pH of acetic acid and NaOH separately.
You can usually get the acid dissociation constants from your textbook’s appendix, then you use that to help you get the concentration/molarity of H, in order to get the pH.
You can use the ion-product constant for water in order to get the molarity of H ( since you know the molarity of OH-).
Someone, please correct me if I did anything wrong. I did this problem at 1 A.M. so I wouldn’t be surprised if there’s a mistake in there somewhere.
I hope you can read this, and good luck! Don’t be afraid to ask more questions.
This is a picture of the benzoic acid that me and my friend recrystallized in the organic chemistry lab.
The original substance was impure benzoic acid and it was heated in a boiling bath of water (while in a test tube), and hot solvent was added until the substance melted.
The substance was then cooled very slowly at a controlled rate of about 2-5 C per minute in order to allow large crystals to form. A controlled, slow cooling allows the crystals to form properly while blocking out most impurities.
The purified substance was then tested by determining it’s melting point. The initial and final melting point was within 1 C, indicating that it was very (but not necessarily entirely) pure.
Titin is a protein that in humans is encoded by the TTN gene. It is a giant protein that functions as a molecular spring which is responsible for the passive elasticity of muscle. It is composed of 244 individually folded protein domains connected by unstructured peptide sequences. These domains unfold when the protein is stretched and refold when the tension is removed. Titin is important in the contraction of striated muscle tissues. With its length of ~27,000 to ~33,000 amino acids—depending on the splice isoform— titin is the largest known protein. (Wikipedia)
Interestingly enough, due to it’s size, it’s actual name is 189,819 letters long. A man was recorded while spending about three hours trying to pronounce the word. If you want to see the length of the word itself, view this link:
The word is also sometimes considered the lengthiest in the English language.
Ernest Rutherford publishes his atomic theory describing the atom as having a central positive nucleus surrounded by negative orbiting electrons. This model suggested that most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space. Rutherford came to this conclusion following the results of his famous gold foil experiment. This experiment involved the firing of radioactive particles through minutely thin metal foils (notably gold) and detecting them using screens coated with zinc sulfide (a scintillator). Rutherford found that although the vast majority of particles passed straight through the foil approximately 1 in 8000 were deflected leading him to his theory that most of the atom was made up of ‘empty space’
I think the Rutherford experiment should be common knowledge.
For those of you that follow bloodredorion AND bloodredorion-science, most of my science rants/lectures will be here from now on.