Formula - Blog Posts
It’s Pi Day!
Pi Day, the informal holiday beloved by math enthusiasts — and even by the math averse — is here! March 14 marks the yearly celebration of the mathematical constant π (pi).
What is Pi?
Pi (3.1415….) is the ratio of circumference to diameter in a circle. Any time you want to find out the distance around a circle when you have the distance across it, you will need this formula.
Despite its frequent appearance in math and science, you can’t write pi as a simple fraction or calculate it by dividing two integers. For this reason, pi is said to be “irrational.” Pi’s digits extend infinitely and without any pattern, adding to its intrigue and mystery.
How Do We Use Pi at NASA?
Measurements: Pi can be used to make measurements – like perimeter, area and volume.
For example, sometimes we use lasers to explode ice samples and study their composition. In this scenario, we can uses pi to calculate the width of the laser beam, which in turn can be used to calculate the amount of energy, or fluence, that hits the ice sample. A larger fluence equals a bigger explosion in the ice.
Commanding Rovers: Pi is also used every day commanding rovers on the Red Planet. Everything from taking images, turning the wheels, driving around, operating the robotic arm and even talking to Earth!
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
Side Dish - Salad Dressing - The Easiest Salad Dressing
It really baffles me how there are hundreds of billions of galaxies in the universe. Hundreds of billions of stars per galaxy. With each star system containing 1-9 planets each. And people still are convinced that this tiny speck of dust we call Earth is the only place you can find intelligent life, let alone life period.
Structural Isomerism
In one boring history lesson, you and your friend (who both love chemistry) are doodling displayed formulas in the back of your textbook. You both decide to draw C5H12 - however, when you come to name what you’ve drawn, your friend has something completely different. You know what you’ve drawn is pentane and your friend knows what they’ve drawn is 2,3-dimethylpropane. So which one is C5H12?
The answer is both! What you and your friend have hypothetically drawn are structural isomers of C5H12 (another is 2-methylbutane). These are compounds which have the same molecular formula but different structural formulas.
Isomers are two or more compounds with the same formula but a different arrangement of atoms in the molecule and often different properties.
There are several different kinds of structural isomers: chain, positional and functional group.
Chain isomerism happens when there is more than one way of arranging carbon atoms in the longest chain. If we continue with the example C5H12, it exists as the three chain isomers shown above. Chain isomers have similar chemical properties but different physical properties because more branched isomers have weaker Van der Waals and therefore lower boiling points.
Positional isomers have the same carbon chain and the same functional group but it is attached at different points along the chain.
This is a halogenoalkane. The locant “1″ describes where the chlorine is on the chain. For more on naming organic compounds, check out my nomenclature post.
The final type of isomer you need to know is a functional group isomer. This is a compound with the same molecular formula but a different functional group. For example, C2H6O could be ethanol or methoxymethane.
And surprisingly, that is all you need to know for the AS exam. There are also things called stereoisomers but those will be covered next year. Just make sure you know how to name and draw the three different kinds of structural isomers for the exam. Practice makes perfect!
SUMMARY
Structural isomers are compounds which have the same molecular formula but different structural formulas.
Isomers are two or more compounds with the same formula but a different arrangement of atoms in the molecule and often different properties.
There are several different kinds of structural isomers: chain, positional and functional group.
Chain isomerism happens when there is more than one way of arranging carbon atoms in the longest chain. Chain isomers have similar chemical properties but different physical properties because more branched isomers have weaker Van der Waals and therefore lower boiling points.
Positional isomers have the same carbon chain and the same functional group but it is attached at different points along the chain.
A functional group isomer is a compound with the same molecular formula but a different functional group.
Happy studying!
Remember that t-shirts designing F1 YouTube video the drivers did last year? Yeah me neither.
Anyways: Mick, Zhou, and Sebastian’s t-shirt designs were something I needed to sketch last year so I’m pulling some old drawings from the vault.
Daniel Ricciardo | The Honey Badger
Chef John's Chocolate Chip Cookies - Desserts Chef John's chocolate chip cookies are almost perfect: crispy on the outside, chewy and chocolaty in the middle, and thin, oh so thin!
We need books that affect us like a disaster, that grieve us deeply, like being banished into forests far from everyone. A book must be the axe for the frozen sea within us. That is my belief.
Franz Kafka