N₀ is the number of C-14 atoms per kg of carbon in the original sample at time = Os when its carbon was of the same kind as that present in the atmosphere today. After time ts, due to radioactive decay, the number of C-14 atoms per kg of carbon is the same sample which has decreased to N. λ is the radioactive decay constant.
Therefore N = N₀e-λt which is the radioactive decay equation,
N₀/N = eλt In (N₀.N= λt. This is the equation 1
The mass of carbon which is present in the sample os mc kg. So the sample has a radioactivity of A/mc decay is/kg. r is the mass of C-14 in original sample at t= 0 per total mass of carbon in a sample which is equal to [(total number of C-14 atoms in the sample at t m=m 0) × ma]/ total mass of carbon in the sample.
Now that the total number of C-14 atoms in the sample at t= 0/ total mass of carbon in sample = N₀ then r = N₀×ma
So N₀ = r/ma. this equation 2.
The activity of the radioactive substance is directly proportional to the number of atoms present at the time.
Activity = A number of decays/ sec = dN/dt = λ(number of atoms of C-14 present at time t) =
λ₁(N×mc). By rearranging we get N = A/(λmc) this is equation 3.
By plugging in equation 2 and 3 and solve t to get
t = 1/λ In (rλmc/m₀A).
4.003 is the mass of helium gas
Answer:
the candle is still solid..................in this case, yes!
Explanation:
it is still solid because the molecules are packed together tighter than the molecules in a liquid or gas.
Answer:
The correct answer is - option D. (check image)
Explanation:
Alkynes and alkenes both decolorized bromine in carbon tetrachloride. The absorption of the IR at about 3300 cm-1 for the X here that are found in the terminal alkynes absorption range only. In presence of excess hydrogen and a nickel catalyst, x gives the 2-methyl pentane.
The most likely structure for X is: CH3-CH3-ch-CH2-C≡CH
Answer:
14.9075 g, 28.67%, 0.11%
Explanation:
The mean concentration of calcium = summation x / frequency
= ( 14.92 + 1491 + 14.88 + 14.92 ) /4 = 14.9075 g
Standard deviation = √(summation (x - μ)² /n) = √ ( ((14.92 - 14.9075)² +(14.91 - 14.9075)² + (14.88 - 14.9075)² + ( 14.92 - 14.9075)²) / 4) = 0.0164
b) percent error = abs(14.9075 - 20.90) / 20.90 × 100 = 28.67%
c) relative standard deviation = standard deviation / mean × 100 = 0.0164 / 14.9075 × 100 = 0.11%
d) The accuracy of the measure is the measurement compared to the actual which according to the standard set by the instructor (5%error) is not very accurate because the percent error is high (28.67%) while the relative standard deviation is quite low ( 0.11%) which means the measurement precision is very high.
The student will have to redo the experiment because the experiment was not too accurate since the percent error is way higher than the set value (5%) although the precision was high.
