Answer: (E) 300 bq
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.
Half life is represented by 
Half life of Thallium-208 = 3.053 min
Thus after 9 minutes , three half lives will be passed, after ist half life, the activity would be reduced to half of original i.e. 
, after second half life, the activity would be reduced to half of 1200 i.e. 
, and after third half life, the activity would be reduced to half of 600 i.e. 
,
Thus the activity 9 minutes later is 300 bq.
In order to find molarity, you must first find the number of moles that was dissolved.
Now, Moles = Mass ÷ Molar Mass
⇒ Moles of NaCl = 2.922 g ÷ 58.44 g/mol
= 0.05 moles
∴ the Molarity of the NaCl is 0.05 M [Option 1]
There are three other structural isomers of 1-butanol: 2-butanol (sec-butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), and 2-methyl-2-propanol (tert-butyl alcohol). 2-Butanol, or sec-butanol, or sec-butyl alcohol, or s-butyl alcohol, is a four-carbon chain, with the OH group on the second carbon.
Chemicals of this type: Ethanol
Hope this helps
Use Ideal Gas equation since values are given in Pressure (P), Volume (V), Temperature (T).
P V = n R T ; n= PV / RT
You can't use 1 mole= 22.4 L equation. Temperature and pressure values are not standard. ( 1 atm, 0
To choose the value of R ( gas constant), check out the units of other values in the equation. They are in atm,liter, kelvin, and mole. So, its value is 0.082 L atm/ K mol.
P= 0.97 atm
V= 35.83 * 10 ⁻³ L (conversion from ml to, just multiplied by 10 ⁻³ )
R= 0.082 L atm/ K mol
T= (25.3 + 273) K ( recall Kelvin = Celcius + 273; K= °C + 273<span>)
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Substitute values into equation of n= PV / RT
n= (0.97 atm) (35.83 * 10 ⁻³ L) / (0.082 L atm/ K mol) (298.3 K)= 0.014 mole
The answer is 0.014 mole
