Uncertainty in Speed [ENDORSED]

[Veronica_Lubera_2A]

The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1% of the hydrogen radius, calculate the uncertainty in the speed of the electron using the Heisenberg uncertainty principle.

So the correct answer is Delta V >= 10^8 m/s. How would you solve the question to receive this answer?

[Chem_Mod]

I will be covering this topic in class during Week 2.

Calculate 1% of the hydrogen radius (0.05 nm) in meters and use it as the uncertainty in position, delta x, of the electron in the Heisenberg Indeterminacy (Uncertainty) Equation.

[Sears 4A]

I do not think we are covering this until week 2, and the week 2 homework can be from review or quantum, so maybe wait until Dr. Lavelle goes over this in lecture!

[AnayaArnold_3L]

The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1% of the hydrogen radius, calculate the uncertainty in the speed of the electron using the Heisenberg uncertainty principle.

So the correct answer is Delta V >= 10^8 m/s. How would you solve the question to receive this answer?

Dr.Lavelle will more than likely go over this concept more in a lecture during week 2 so I wouldn't worry about it too much as of right now.

[KatherineValdez_4B]

I really hope he does cover it because I'm confused.

[andrewcj 2C]

I think it goes like this:
(p)(x) = (1/2)(h/2)
(p) = m(v)
From here you can plug in (0.01)*(0.05 nm) for x and solve.

[andrewcj 2C]

One additional thing for my reply, make sure you convert nm to m.

[nicole-2B]

One additional thing for my reply, make sure you convert nm to m.

thanks for clarifying this.

[melinak1]

One additional thing for my reply, make sure you convert nm to m.

ohh ok thank you!

[KatherineValdez_4B]

One additional thing for my reply, make sure you convert nm to m.

Thanks for this I almost forgot to do it.

[Aprice_1J]

Another important conceptual thing to think about is that the more you know about the position of an electron, the less we know about its velocity- they have an inverse relationship.

[Anvi Brahmbhatt 4A]

I think it goes like this:
(p)(x) = (1/2)(h/2)
(p) = m(v)
From here you can plug in (0.01)*(0.05 nm) for x and solve.

Thank you for the explanation!

[Claire Stoecklein 1E]

When you determine delta p for the indeterminacy equation, make sure to use p=mv, using the velocity given in the equation and the mass of electron, 9.109 x 10^-31.

[brennayoung]

This equation can be used for other atoms than hydrogen right?

[Ruth Glauber 1C]

I think you need to calculate 1% of the hydrogen radius (0.05 nm) in meters for the uncertainty.

[Caitlin Ciardelli 3E]

Another way to calc uncertainty in v:

10 ms^-1 +/- .5
You can take the +/- value and multiply it by 2. This is another way to find uncertainty in v

[CMaduno_1L]

In response to Brennayoung's question, I believe that we will only be applying this to hydrogen for now. This principle is used when measuring position and momentum of a particle.

[Sara Richmond 2K]

Use these equations:
(delta p)(delta x) = (1/2)(h/4 PIE)
(deltap) = m( delta v)

Sometimes this type of problem can be confusing because they dont give you the delta p equation.

Also remember to multiply the delta v uncertainty by 2 because it is plus or minus a certain amount.

[Mitchell Koss 4G]

Also, don’t confuse frequency (v) with velocity (v)

[Jack_Pearce_2H]

you would use the heisenberg uncertainty equations to solve this but more likely than not the result would be very off because the electron is known to a very close degree of certainty

[305405193]

If you need more help solving for these uncertainty questions this YouTube video really helped me get through these types of problems here is the link: https://www.youtube.com/watch?v=BNYz5EKXVeI

[Harrington Bubb3A]

I really hope he does cover it because I'm confused.

Right?! I thought this was a physics question at first and didn't even read through it until I realized it was a chem problem.

[Harrington Bubb3A]

Also, don’t confuse frequency (v) with velocity (v)

I thought frequency was denoted with a lowercase f? Could be wrong that is based off of my physics class I took 3 years ago!

[Jacob Kirkosian 3C]

I believe that both a lowercase f and the Greek letter nu (which looks very similar to a v) can be used to denote frequency. However, nu is more often used when the frequency is related to electromagnetic waves.

[105784203]

The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1% of the hydrogen radius, calculate the uncertainty in the speed of the electron using the Heisenberg uncertainty principle.

So the correct answer is Delta V >= 10^8 m/s. How would you solve the question to receive this answer?

We will be covering this in weeks 2 and 3, you should wait until then to dive into these questions, its great that you are getting ahead though!

[kareena_prasad]

I think it is interesting how you can't determine the position and the speed of an electron at the same time. You can only find one if you have the other.

[605703266]

convert the radius into m and then multiply it by two to find the diameter which will act as your change in position (delta x). to find the mass of a hydrogen atom, convert the molar mass into kg/mol (SI units). you would take the molar mass, divide it by 1000 to convert into kg, and then use avogadro's number for the atoms. this acts as your mass. plug it all in the heisenberg equation and then solve for delta v (speed). note that momentum can also be written as mass times velocity so that's how you would solve for velocity.

[605703266]

convert the radius into m and then multiply it by two to find the diameter which will act as your change in position (delta x). to find the mass of a hydrogen atom, convert the molar mass into kg/mol (SI units). you would take the molar mass, divide it by 1000 to convert into kg, and then use avogadro's number for the atoms. this acts as your mass. plug it all in the heisenberg equation and then solve for delta v (speed). note that momentum can also be written as mass times velocity so that's how you would solve for velocity.

[Joellen 1B]

I would use the Heisenberg uncertainty equation which is the uncertainty in momentum multiplied by the uncertainty in position is greater than or equal to planck's constant over 4pi. The uncertainty in momentum is equal to mass times the uncertainty in velocity, so you could use that in solving. But overall, I would remember that the uncertainty in position would be the radius you were given multiplied by two to get the diameter.

[kayleec1004]

Heisenberg uncertainty equation (radius times two = the diameter).

[605537776]

Make sure to pay attention to units!

[Sophia Hartwell 1F]

I'm confused about this as well but based on the syllabus this should be covered in week 2 so hopefully he will go over it then.