From the calculations, the half life of the material is 6.5 days.
<h3>What is radioactivity?</h3>
The term radioactivity has to do with the spontaneous disintegration of a specie.
Uisng the formula;
N=Noe^-kt
N= amount at time t = 0.135 Ci or 4.995 ×10^9 Bq
No = amount initially present = 1.75 x 10^12 Bq
k = rate constant = ?
t = time taken = 55 days
Hence;
4.995 ×10^9 = 1.75 x 10^12e^-55k
4.995 ×10^9/1.75 x 10^12 = e^-55k
2.85 * 10^-3 = e^-55k
ln2.85 * 10^-3 = -55k
k = ln2.85 * 10^-3/-55
k = 0.1066 day-1
Half life = 0.693/ 0.1066 day-1
= 6.5 days
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Answer:
SPECIFIC HEAT CAPACITY
Explanation:
Q = MC DELTA T
q = heat
c = specific heat
T = temperature ( final - initial )
<span>Metals tend to lose electrons and form electro-positive ions / cations.</span>
Work out the number of moles in
100.00 grams of the oxide.
For nitrogen: The atomic mass of N is 14.0067, and we have 36.84 g N:
36.84 g N14.0067 g N/mol N=2.630 mol N
For oxygen: The atomic mass of O is
15.9994, and we have
100.00−36.84=63.16 g O:
63.16 g N 15.9994 g N/mol N=3.948 mol N
Now the ratio 3.958 2.630 is very close to
1.5=32
. So we conclude that the gas has three moles
O to two moles N making the empirical formula
N2O3.
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Hydrogen bonds
Guanine-cytosine and adenine-thymine <em>hydrogen bonds</em> hold the strands of a DNA helix together.