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izaakha
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Hi, I have two questions that I am stuck on:
1. The pK a of HEPES buffer at room temperature is 7.5. What is the acid dissociation constant K a?
a)18.7 nM-1
b)18.7 nM
c)31.6 nM-1
d)31.6 nM
I think it is d) 31.6, but not sure.
2. The radioactivity of an isotope R decays exponentially with time according to R = R0exp(-0.35t) where t is the time in days and R0 is the radioactivity at zero time.
What fraction of the initial radioactivity will remain after 6 days?
a)12.2%
b)8.3%
c)6.1%
d)10.5%
Don't even know where to start on this one
Thanks
1. The pK a of HEPES buffer at room temperature is 7.5. What is the acid dissociation constant K a?
a)18.7 nM-1
b)18.7 nM
c)31.6 nM-1
d)31.6 nM
I think it is d) 31.6, but not sure.
2. The radioactivity of an isotope R decays exponentially with time according to R = R0exp(-0.35t) where t is the time in days and R0 is the radioactivity at zero time.
What fraction of the initial radioactivity will remain after 6 days?
a)12.2%
b)8.3%
c)6.1%
d)10.5%
Don't even know where to start on this one
Thanks
Last edited by izaakha; 9 months ago
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lordaxil
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#2
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#2
1. d) is right
2. R/R0 = exp(-0.35t) is the fraction of initial radioactivity at time t. You are given t, so just sub in.
2. R/R0 = exp(-0.35t) is the fraction of initial radioactivity at time t. You are given t, so just sub in.
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izaakha
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#3
(Original post by lordaxil)
1. d) is right
2. R/R0 = exp(-0.35t) is the fraction of initial radioactivity at time t. You are given t, so just sub in.
1. d) is right
2. R/R0 = exp(-0.35t) is the fraction of initial radioactivity at time t. You are given t, so just sub in.
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izaakha
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#4
(Original post by lordaxil)
1. d) is right
2. R/R0 = exp(-0.35t) is the fraction of initial radioactivity at time t. You are given t, so just sub in.
1. d) is right
2. R/R0 = exp(-0.35t) is the fraction of initial radioactivity at time t. You are given t, so just sub in.
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lordaxil
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#5
I'mF*cked
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