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
It’s A
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Anything greater that 7 is a base....so 13 would be a very strong base for example a drain cleaner. Hopefully this is what you are looking for.
A change in the force of gravity on an object will affect its weight.
Answer:
1HydrogenH2HeliumHe3LithiumLi4BerylliumBe5BoronB6CarbonC7NitrogenN8OxygenO9FluorineF10NeonNe11SodiumNa12MagnesiumMg13AluminiumAl14SiliconSi15PhosphorusP16SulfurS17ChlorineCl18ArgonAr19PotassiumK20CalciumCa
