Looking for some assistance doing a few chemistry problems. Will tip for help in setting them up (and of course eventually arriving at a correct answer).


First problem relates to wavelength, velocity, and such:




How fast (in miles per hour) would you have to throw a rock if you wanted the rock to have a wavelength of 2.36 x 10 -26 nm. The rock weighs 10 ounces.



I'm guessing this involves working backwards to find the answer? Not sure as to where to begin though.

This post was edited by chicano on Jun 28 2015 02:04pm

Lambda= h/(mv)



lambda= wavelength
h= planck const
m=mass
v= velocity

This post was edited by saber_x3 on Jun 28 2015 02:16pm

2.36 x 10^-26 nm = (6.63 x 10^-34 J/s) / (10 oz) ( x )

Am I solving for velocity?

This post was edited by chicano on Jun 28 2015 02:30pm

are you converting your units properly?





sounds like it.

This post was edited by carteblanche on Jun 28 2015 02:32pm

well 10 ounces needs to be converted to kg and nanometers to meters I guess?


2.36 x 10^-35 m/s = (6.63 x 10^-34 J/s) / (.28349523125000003 kg) ( x )

dont forget miles and hours

I don't know what you mean? How do I solve for v?

i was referring to the units you need to convert. the problem doesnt give you miles or hours, but your final answer needs to be in miles per hour.

you already have the formula. what are you asking? re-arrange for v. make sure you convert units as needed

This post was edited by carteblanche on Jun 28 2015 02:57pm

Kinda confusing when it's a denominator, how would I isolate velocity?

Uh,treat the variables like objects.

you want v on one side,

Lambda= h/(mv)

since v is on the bottom (denominator ) , you can move it to the left side

lambbda *v =h/m

then get rid of lambda that's on the top to the bottom of the right side

v=h/(m*lambda)