Cambridge Chemistry Challenge

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Currently working on it

Im working on gold too, some sort of element i thought at first but then realised the arrow, so maybe some enthalpy value

Reply 401

Cubic

Original post by david2457

Im working on gold too, some sort of element i thought at first but then realised the arrow, so maybe some enthalpy value

I'm only doing gcse science, can you clarify whether or not enthalpy is change of energy?

My starting point was googling 'Hartree'.

Edit: Tried multiplying the bohr radii by value in angstroms: ≈ 0.53 Å and calculating au from there, didn't work.
(0.741152 and 614.764)

Edit 2: Does anyone know what the background is? I assumed it was light (orange emited photons) but now I'm not sure.

(edited 11 years ago)

gold is difficult

Original post by chemistinthemaking

gold is difficult

I wouldnt know im still stuck on copper.... :cry2:

clues for copper?

Original post by Cubic

http://en.wikipedia.org/wiki/Hartree

Try wikipediaing the Hartree and use the last equivalent formula for energy on hartrees. Yes enthaltpy is change of energy, or energy used/required.

(edited 11 years ago)

Reply 406

chemistinthemaking

Original post by david2457

Try wikipediaing the Hartree and use the last equivalent formula for energy on hartrees. Yes enthaltpy is change of energy, or energy used/required.

have you done it?

Reply 407

david2457

Original post by chemistinthemaking

have you done it?

No I'm stuck, has anyone done it?

Reply 408

Cubic

Original post by david2457

Try wikipediaing the Hartree and use the last equivalent formula for energy on hartrees. Yes enthaltpy is change of energy, or energy used/required.

Ah, I thought so, we've been referring to it as deltaH in school.

This equation?

E_\mathrm{h} = {\hbar^2 \over {m_\mathrm{e} a^2_0}} = m_\mathrm{e}\left(\frac{e^2}{4\pi\epsilon_0\hbar}\right)^2 = m_\mathrm{e}c^2\alpha^2 = {\hbar c \alpha \over {a_0}}

Reply 409

chantelleeee

Can anybody help me with silver?

Reply 410

Oromis263

Original post by david2457

http://en.wikipedia.org/wiki/Hartree

Try wikipediaing the Hartree and use the last equivalent formula for energy on hartrees. Yes enthaltpy is change of energy, or energy used/required.

Is that supposed to give the answer or?
I have a value using that, it's just a pain to enter in..

Reply 411

Cubic

Original post by chantelleeee

Can anybody help me with silver?

Google the names of top two rows (represented by letters) and find what's common between them.

Reply 412

Me123456789

Original post by Cubic

can you give me a clue for copper please

Reply 413

chemistinthemaking

Original post by Oromis263

Is that supposed to give the answer or?
I have a value using that, it's just a pain to enter in..

same lol

Reply 414

david2457

Original post by Cubic

Ah, I thought so, we've been referring to it as deltaH in school.

This equation?

E_\mathrm{h} = {\hbar^2 \over {m_\mathrm{e} a^2_0}} = m_\mathrm{e}\left(\frac{e^2}{4\pi\epsilon_0\hbar}\right)^2 = m_\mathrm{e}c^2\alpha^2 = {\hbar c \alpha \over {a_0}}

Yes, I'm not sure if this is right though

Reply 415

Cubic

Original post by Me123456789

can you give me a clue for copper please

Find what the number 3 has to do with CaCO3, wikipedia will help.

Reply 416

polkadotty5

Yeah I immediately tried doing the last equation:
(h dash x c x a)/a0
but it didn't work...
Has anyone worked out the significance of the background?

Reply 417

david2457

Want value have you got?

Reply 418

david2457

Original post by polkadotty5

Yeah I immediately tried doing the last equation:
(h dash x c x a)/a0
but it didn't work...
Has anyone worked out the significance of the background?

What was gold?

Reply 419

PhysicsN

guessing so far....

graph of potential energy against distance.

graph in background = solar flare

proton + proton collision, energy require to overcome coulomb barrier

however, straight line indicates quantum tunneling.

STUCK!