MCAT Chem

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amu

1 amu = 1.66 x 10^-27
mass number

protons + neutrons
E_photon
- hf = h (c/)
- planck's constant * frequency
- frequency = speed of light / wavelength
Planck's constant - h

6.63 x 10^-34J*s
alpha particle - (He)
- 2 protons and 2 neutrons emitted
- Ex: ²¹⁰₈₄Po --> ²⁰⁶₈₂Pb + ⁴₂
- subtracts 4 from mass number
- subtracts 2 from atomic number
beta decay - ^-
- 1 neutron is converted into a proton and an electron.
- proton and electron (electron is emitted)
- Mass number remains the same
- Ex: ¹⁴₆C --> ¹⁴₇N + ⁰_-1e-
- Occurs when high neutron to proton ratio
- adds 1 to atomic number
⁺decay
- 1 proton is converted into a neutron and a positron
- neutron and positron (positron is emitted)
- Mass number remains the same
- Ex: ¹⁸₉F --> ¹⁸₈O + ⁰₊₁e+
- Occurs when high proton to neutron ratio
- subtracts 1 from atomic number
Electron capture
- 1 electron is captured to convert a proton into a neutron
- Similar to ⁺ ejection (positron emission)
- Mass number to stay the same
- Ex: ⁵¹₂₄Cr + ⁰_-1e- --> ⁵¹₂₃V
- Occurs when high proton to neutron ratio
- subtracts 1 from atomic number
Gamma Decay
- Gamma Rays have neither mass nor charge
- Neither mass number nor atomic number change
- Ex: ³¹₁₄Si --^-decay---> ³¹₁₅P* -- decay-> ³¹₁₅P +
mass defect - m
- total mass of separate nucleons - mass of nucleus
- will always be positive
E_B - Einstein's binding energy equation

mc²= m(in amu) x 931.5MeV
In Binding energy 1 kg =

9 x 10¹⁶J
c²- speed of light squared

9 x 10¹⁶
Half life - t_1/2
- N = N₀e^-kt
- N = N₀(1/2)^t/t_1/2
- k = (ln 2)/t_1/2

Author

nextMD

191663

Card Set

MCAT Chem

Description

MCAT Chem

Updated

2013-01-08T18:41:40Z

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