Answer:
The correct answer is: d. The pKa of the chosen buffer should be close to the optimal pH for the biochemical reaction.
Explanation:
The buffer resist or maintain the change in pH in case of Acid or basic addition to the solution. The buffer capacity should be within one or two pH units when compared to the optimal pH.
Thus it is important to select a buffer with pKa close to the optimum pH of the reaction because the ability for the buffer to maintain the pH is is great at the pH close to pKa.
Answer : The volume of pure diamond is 
Explanation : Given,
Density of pure carbon in diamond = 
Moles of pure diamond = 23.7 moles
Molar mass of carbon = 12 g/mol
First we have to calculate the mass of carbon or pure diamond.
Molar mass of carbon = 12 g/mol

Now we have to calculate the volume of carbon or pure diamond.
Formula used:

Now putting all the given values in this formula, we get:

Volume = 
As we know that:

So,
Volume = 
Volume = 
Therefore, the volume of pure diamond is 
You have to find the gram formula mass of C6H6 then do mass (g) = mol x GFM
Answer:
Explanation:
C₂H₂ + 2H₂ = C₂H₆
1 mole 2 mole 1 mole
Feed of reactant is 1.6 mole H₂ / mole C₂H₂
or 1.6 mole of H₂ for 1 mole of C₂H₂
required ratio as per chemical reaction written above
2 mole of H₂ for 1 mole of C₂H₂
So H₂ is in short supply . Hence it is limiting reagent .
1.6 mole of H₂ will react with half of 1.6 mole or .8 mole of C₂H₂ to form .8 mole of C₂H₆
a )Calculate the stoichiometric reactant ratio = mole H₂ reacted/mole C₂H₂ reacted
= 1.6 / .8 = 2 .
b )
yield ratio = mole C₂H₆ formed / mole H₂ reacted ) = 0.8 / 1.6 = 1/2 = 0.5 .
Each year over 100,000 new organic compounds are produce