Polaris the north star is very bright and it doesn’t move
The half-life of Th-232 is 1.405 × 10¹⁰ years
Time elapsed = 2.8 x 10⁹ years
Equation of radioactive decay:
A = A₀ = (1/2)^ t/t₁/₂
where A₀ is the initial amount, A is the amount after time t, t₁/₂ is the half file
The fraction of thorium-232 that remains in the rock after 2.8 billions years is,
A/A₀ = (1/2) ^ (2.8 x 10⁹/ 1.405 × 10¹⁰) = 0.871
Therefore, the percentage of thorium-232 in the rock that was dated at 2.8 billions year = 87.1%
Answer:
The answer is given below
Explanation:
Cys 278 residue is the only available cysteine which is alkylated by the addition of N-Ethylmaleimide or NEM (alkylating agent). It works by only alkylating the sulfhydryls. In this case, Cys 278 residue is the only one which has exposed cysteine residue.
While the other residues have their sulfhydryls group either involved in the synthesis of disulfide bonds of proteins or their Cys residues are intrinsically placed in the proteins and cannot be alkylated with NEM.
NEM cannot alkylate if its protein is not available in the free form or it is in bounded form. For NEM to alkylate Cys 278, it should be free and should have sulfhydryls available for alkylation.
Alkylation: it is the transfer of alkyl groups. Alkyl groups contain Hydrogen and Carbon in their structure.
ZnS(s) + 2O₂(g) ⇒ZnSO₄(s)
<h3>Further explanation</h3>
The oxidation-reduction reaction or abbreviated as Redox is a chemical reaction in which there is a change in oxidation number
Oxidation is an increase in oxidation number, while reduction is a decrease in oxidation number.
Reaction
ZnS(s) + 2O₂(g) ⇒ZnSO₄(s)
S²⁻ (-2 in ZnS) to S⁺⁶(+6 in ZnSO₄) ⇒ oxidation
O₂(0 in O₂) to O⁻²(-2 in ZnSO₄)⇒ reduction
Answer:
Depending upon the mass gathered, the next process formation varies:
Nuclear fusion can kick in leading to formation of star. The nuclei fuse to together and energy is liberated in the form of light and heat.
If sufficient mass is not gathered to start nuclear fusion reaction, gaseous planet forms like Jupiter.
In third case, even though sufficient mass is present (twice the mass of Jupiter) still no fusion reaction starts. Such bodies are known as failed stars or brown dwarfs.
