Answer:
Mass of original sample = 100 g
Explanation:
Half life of cesium-137 = 30.17 years
Where, k is rate constant
So,
The rate constant, k = 0.02297 year⁻¹
Time = 90.6 years
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration
Initial concentration = ?
Final concentration = 12.5 grams
Applying in the above equation, we get that:-
![12.5\ g=[A_0]e^{-0.02297\times 90.6}](https://tex.z-dn.net/?f=12.5%5C%20g%3D%5BA_0%5De%5E%7B-0.02297%5Ctimes%2090.6%7D)
![[A_0]=\frac{12.5}{e^{-0.02297\times 90.6}}\ g=100\ g](https://tex.z-dn.net/?f=%5BA_0%5D%3D%5Cfrac%7B12.5%7D%7Be%5E%7B-0.02297%5Ctimes%2090.6%7D%7D%5C%20g%3D100%5C%20g)
<u>Mass of original sample = 100 g</u>
Answer:
The correct answer will be option-D.
Explanation:
The semi-conservative mode of replication is the common method of replication used by mostly organisms on earth which were demonstrated by the Meselson and Stahl in 1958.
They used the isotopes of the nitrogen which contains extra neuron which makes the nitrogen-heavy and cultured them in bacteria
The experiment concluded that newly replicated double stranded DNA contains one newly synthesized DNA strand which is complementary to another parental strand. Thus new DNA molecule has one parental strand while other newly synthesized strand.
This is best illustrated by the option-D in the figure and therefore is the correct answer.
Wurtz reaction is a special type of organic reaction involving the synthesis of aliphatic hydrocarbons from two molecules of an alkyl halide and two atoms of sodium in the presence of dry ether solution
Please bear in mind that wurtz reaction fails whenever tertiary alkyl halides are used.
An example of Wurtz reaction is given below:
2R – X + 2Na → R–R + 2Na + X−
<h3>What are organic compounds?</h3>
Organic compounds can simply be defined as those classes of organic molecules which contain carbon atoms covalently bonded to hydrogen atoms (C-H bonds).
Below are some few general characteristics of organic compounds:
- All organic compounds contain carbon.
- Most of them are flammable.
- They are all soluble in non-polar solvents
- Most organic compounds / substances are covalently bonded molecules
Some classes of organic compounds are:
So therefore, Wurtz reaction is a special type of organic reaction involving the synthesis of aliphatic hydrocarbons from two molecules of an alkyl halide and two atoms of sodium in the presence of dry ether solution
Learn more about organic compounds:
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Answer:
The percentage yield of O2 is 66.7%
Explanation:
Reaction for decomposition of potassium chlorate is:
2KClO₃ → 2KCl + 3O₂
The products are potassium chloride and oxygen.
Let's find out the moles of chlorate.
Mass / Molar mass = Moles
12.3 g / 123 g/mol = 0.1 mol
So ratio is 2:3, 2 moles of chlorate produce 3 mol of oxygen.
Then, 0.1 mol of chlorate may produce (0.1 .3)/ 2 = 0.15 moles
Let's convert the moles of produced oxygen, as to find out the theoretical yield.
0.15 mol . 32 g/ 1mol = 4.8 g
To calculate the percentage yield, the formula is
(Produced Yield / Theoretical yield) . 100 =
(3.2g / 4.8g) . 100 = 66.7 %
Answer : The concentration of the NaOH solution is, 0.738 M
Explanation :
To calculate the concentration of base, we use the equation given by neutralization reaction:
where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:
Putting values in above equation, we get:
Thus, the concentration of the NaOH solution is, 0.738 M
