Answer:
6.73g
Explanation:
T½ = 5.2days
No = 80g
N = ?
T = 20.8days
We'll have to find the disintegration constant first so that we can plug it into the equation that will help us find the mass of the sample after 20.8 days
T½ = In2 / λ
T½ = half life
λ = disintegration constant
λ = In2 / T½
λ = 0.693 / 5.8
λ = 0.119
In(N / No) = -λt
N = final mass of the radioactive sample
No = initial mass of the sample
λ = disintegration constant
t = time for the radioactive decay
In(N/No) = -λt
N / No = e^-λt
N = No(e^-λt)
N = 80 × e^-(0.119 × 20.8)
N = 80 × e^-2.4752
N = 80 × 0.0841
N = 6.728g
The mass of the sample after 20.8 days is approximately 6.73g
Answer:
(A) The statement is false. The starting material is favored at equilibrium
Explanation:
As we know that type of reaction is predicted by value Gibbs free energy.
ΔG >0 It means that reaction is non spontaneous and favors the reactant of the reaction.
ΔG <0 It means that reaction is spontaneous and favors the product of the reaction.
As we know that
ΔG = ΔH -T ΔS
Here given that Assume the entropy term is small compared to the enthalpy term so ΔS = 0
⇒ ΔG = ΔH
Given that
ΔH o = 65 kJ/mol,
ΔG = ΔH = 65 kJ/mol
ΔG >0 It means that reaction is non spontaneous and favors the reactant of the reaction.
So the option A is correct.
(A) The statement is false. The starting material is favored at equilibrium.
Answer:
The sum of the numbers of protons and neutrons in the nucleus is called the mass number and, expressed in amu, is approximately equal to the mass of the atom. An atom is neutral when it contains equal numbers of electrons and protons.
Explanation:
hope this helps :)
When fully bonded to other atoms, the four bonds of the carbon atom are directed to the corners of a tetrahedron and make angles of about 109.5° with each other (see chemical bonding: Bonds between atoms).