Units

Science questions not covered in Chem 14A and 14B. Try to limit questions to chemistry (inorganic chemistry, physical chemistry, organic chemistry, biophysical chemistry, biochemistry, materials science, environmental chemistry).

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ariaterango_1A
Posts: 57
Joined: Wed Sep 18, 2019 12:15 am

Units

Postby ariaterango_1A » Tue Oct 22, 2019 2:59 pm

I'm having trouble with units when conducting some of these problems. Could anyone help me with the units of velocity, threshold energy, Plank's constant, and frequency?

Reina Robles 2B
Posts: 71
Joined: Fri Aug 09, 2019 12:16 am

Re: Units

Postby Reina Robles 2B » Tue Oct 22, 2019 3:19 pm

Velocity: meters per second
Threshold energy: Joules
Plank's constant: Joules times seconds
Frequency: Hz (which is also cycles per second)

You can also find these on the constants and equations sheet that they give us during tests:
https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf

I hope this helps!

Rebecca Remple 1C
Posts: 137
Joined: Wed Sep 18, 2019 12:16 am
Been upvoted: 1 time

Re: Units

Postby Rebecca Remple 1C » Tue Oct 22, 2019 3:32 pm

Reina Robles 1H wrote:Velocity: meters per second
Threshold energy: Joules
Plank's constant: Joules times seconds
Frequency: Hz (which is also cycles per second)

You can also find these on the constants and equations sheet that they give us during tests:
https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf

I hope this helps!

I completely agree with Reina's advice! Also, I highly recommend using the constants and equations sheet while solving homework problems to simulate a test situation. Additionally, I wanted to note that 1 Joule is equivalent to 1 kg⋅m2⋅s−2. This can help you cancel units, depending on what you're solving for. This conversion used to trip me up and it shows up a lot in the homework problems. I hope this helps!

-Rebecca

Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

Re: Units

Postby Tiffany Chao 2H » Tue Oct 22, 2019 9:06 pm

velocity: m/s
threshold energy: J or kg. m^2. s^-2
Planck's constant: 6.626 x 10^-34 Js or kg.m^2. s^-1
frequency: Hz or s^-1

ariaterango_1A
Posts: 57
Joined: Wed Sep 18, 2019 12:15 am

Re: Units

Postby ariaterango_1A » Tue Oct 29, 2019 2:25 pm

Thank you everyone! I didn't realize we would be provided a list of constants. It would be a good idea for me to do the practice problems with this sheet to cancel out units.


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