AAMC sample test C/P #38, #52

[medbunny56]

Hi guys!

can anyone explain the solutions to these questions please? i didn't understand the aamc solution explanation so well :/

38. expected carbon labeling pattern

52. What is the freq of the emitted gamma photons? (solution: 3.38x10^19hz)

i would really appreciate it! thanks so much

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[aldol16]

Can you give more details about the questions? Most of us are probably too lazy to look it up. For 38, if it's the one I'm thinking of, you just have to follow the mechanism throughout. Label your carbons and follow the chemical logic. It's nothing you can memorize.

 

[medbunny56]

 

[aldol16]

Oh. Just use the equation E = h*f. This is one you should commit to memory. I think it gives you the energy in units of electron volts and so you need to convert that to joules first. You can either look up the conversion factor or, on MCAT day, you can look at the units. Volts are also known as joules per coulomb and so an electron volt is literally e*V = e*J/C.

 

[medbunny56]

Oh. Just use the equation E = h*f. This is one you should commit to memory. I think it gives you the energy in units of electron volts and so you need to convert that to joules first. You can either look up the conversion factor or, on MCAT day, you can look at the units. Volts are also known as joules per coulomb and so an electron volt is literally e*V = e*J/C.

Thanks! So the passage states the energy is 130Kev but do I need to use the value of the elementary charge (1.6x10^-19) also?

 

[aldol16]

Thanks! So the passage states the energy is 130Kev but do I need to use the value of the elementary charge (1.6x10^-19) also?

Yes, you will need to use the value of the elementary charge because 130 eV is 130*1.609e-19 joules.