The correct answer is D. Because sulfur has 6 electrons in its outermost shell
Answer:
C. Trp D. Phe E. Tyr
Explanation:
The concentration of a protein has a direct relation with absorbance of the protein in a UV spectrophotometer. The formula which relates concentration with absorbance is described as under:
A = ∈ x c x l
where, A = Absorbance
∈ = Molar extinction co-efficient
c = Concentration of absorbing species i.e. protein
l = Path length of light
Tryptophan (Trp), phenylalanine (Phe ) and tyrosine (Tyr) are three aromatic amino acids which are used to measure protein concentration by UV. It is mainly because of tryptophan (Trp), protein absorbs at 280 nm which gives us an idea of protein concentration during UV spectroscopy.
The table depicting the wavelength at which these amino acids absorb and their respective molar extinction coefficient is as under:
Amino acid Wavelength Molar extinction co-efficient (∈)
Tryptophan 282 nm 5690
Tyrosine 274 nm 1280
Phenylalanine 257 nm 570
In view of table above, we can easily see that Molar extinction co-efficient (∈) of Tryptophan is highest amongst all these 3 amino acids that is why it dominates while measuring concentration.
there are 2 copper atoms on the left side of the arrow, but none on the other side. there are also 7 oxygen atoms on the left hand side, but only 5 on the right hand side of the arrow.
Mg + 1/2 O2 → MgO
1 mol = 24 g of Mg
X mol = 12 g of Mg
x = 0.5 moles of Mg
Mg :MgO = 1:1 (coefficient from equations using mole ratio)
So
0.5 moles of MgO
1 mol MgO = (24+16) g = 40 g
0.5 moles of MgO = 0.5 × 40
= 20 g of MgO produced
