Answer:
a) a0 was 46.2 grams
b) It will take 259 years
c) The fossil is 1845 years old
Explanation:
<em>An unknown radioactive substance has a half-life of 3.20hours . If 46.2g of the substance is currently present, what mass A0 was present 8.00 hours ago?</em>
A = A0 * (1/2)^(t/h)
⇒ with A = the final amount = 46.2 grams
⇒ A0 = the original amount
⇒ t = time = 8 hours
⇒ h = half-life time = 3.2 hours
46.2 = Ao*(1/2)^(8/3.2)
Ao = 261.35 grams
<em>Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0% of an Am-241 sample to decay?</em>
t = (ln(0.66))-0.693) * 432 = 259 years
It will take 259 years
<em>A fossil was analyzed and determined to have a carbon-14 level that is 80% that of living organisms. The half-life of C-14 is 5730 years. How old is the fossil?</em>
<em />
t = (ln(0.80))-0.693) * 5730 = 1845
The fossil is 1845 years old
At the Earth's North Pole, the north celestial pole is directly overhead, and all stars that are visible at all (that is, all stars in the northern celestial hemisphere) are circumpolar. As one travels south, the north celestial pole moves towards the northern horizon
Answer:
The alkyl halide is secondary
The nucleophile is a poor nucleophile
The solvent is a protic solvent
The product is racemic
Explanation:
The reaction is shown in the image attached.
Alkyl halides undergo nucleophilic substitution by two mechanisms; SN1 and SN2. The particular mechanism that applies depends on;
I) structure of the alkyl halide
ii) nature of the nucleophile
iii) nature of the solvent
Looking at the reaction under review, we can see from the structure that the alkyl halide is a secondary alkyl halide. A secondary alkyl halide may undergo substitution via SN1 or SN2 mechanism depending on the conditions of the reaction.
If the nucleophile is poor, and the solvent is protic, SN1 mechanism is favoured over SN2 mechanism. Since CH3CH2OH is a poor nucleophile and ethanol is a protic solvent, we expect the reaction to proceed via SN1 mechanism leading to the formation of a racemic product.
The organic product is also shown in the second image attached.
Answer:
I dont know what the answer is
Explanation: