Answer:
Vertebrates, invertebrates, and amphibians.
Explanation:
Vertebrates have backbones. Frogs have back bones.
Invertebrates do not have backbones. Hermit crabs do not have back bones.
Amphibians are cold-blooded vertebrate animals. Frogs are cold-blooded vertebrate animals.
Answer:
0.607mol
Explanation:
n(AR) = mass / molar máss
= 24.3 /40
=0.607
Answer :
The correct answer for primary component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
<u>Buffer solution :</u>
It is a solution of mixture of weak acid and its conjugate base OR weak base and its conjugate acid . It resist any change in solution when small amount of strong acid or base is added .
<u>Capacity of a good buffer : </u>
A good buffer is identified when pH = pKa .
From Hasselbalch - Henderson equation which is as follows :
![pH = pka + log \frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=pH%20%3D%20pka%20%2B%20log%20%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
If [A⁻] = [HA] ,
pH = pka + log 1
pH = pKa
This determines that if concentration of weak acid and its conjugate base are changed in small quantity , the capacity of buffer to maintain a constant pH is greatest at pka . If the amount of [A⁻] or [HA] is changed in large amount , the log value deviates more than +/- 1M and hence pH .
Hence Buffer has best capacity at pH = pka .
<u>Phosphate Buffer : </u>
Phosphate may have three types of acid-base pairs at different pka ( shown in image ).
Since the question is asking the pH = 7.4
At pH = 7.4 , the best phosphate buffer will have pka near to 7.4 .
If image is checked the acid - base pair " H₂PO₄⁻ and HPO₄²⁻ has pka 7.2 which is near to pH = 7.4 .
Hence we can say , the primary chemical component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
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E = mc^2
<span>where E is the energy in joules, </span>
<span>m is the mass in kilograms, </span>
<span>and c is the speed of light. </span>
<span>E = mc^2 </span>
<span>E = (5.63 x 10^-7 kg)(3 x 10^8 m/s)^2 </span>
<span>E = 5.07 x 10^10 J </span>
2Na (s) + Cl2 (g) = 2NaCl (s)