Answer:
60.08g/mol
Explanation:
Given parameters:
Formula of sand = SiO₂
Find the molar mass of the compound to the hundredths place;
Molar mass of Si = 28.085g/mol
Molar mass of O = 15.999
Molar mass = 28.085 + 2(15.999) = 60.08g/mol
Answer:
To maintain a pH value of 8.8 in a particular solution the best option is Tris or boric acid.
Explanation:
To decide a good acid/conjugate base pair it is necessary to know the pKa of the acids because every buffer has an optimal effective range due to pH = pKa ± 1. The closer the working pH is to the acid pKa, the buffer will be more effective. Below is the list of the pKa of the different option.
Acetic acid: pKa = 4.76
Boric acid: pKa1 = 9.24 pKa2 = 12.74 pKa3 = 13.80
Ascorbic acid: pKa1 = 4.17 pKa2 = 11.57
Tris: pKa = 8.06
Acetic and Ascorbic acid are too far from the range of 8.8. Thus the best options are boric acid or Tris. To define between these two it is necessary to consider other factors like interaction between components of the solution and the ionic strength required.
Answer:
B. II.
Explanation:
The idea of recrystallization works when the solubility of the target substance decreases as the temperature of the solution decreases.
The method of recrystallization involves dissolving the solute in a suitable hot solvent and then allow the solution to cool gradually. The pure solute dissolves in the hot solvent and then separates out of the solution as it is cooled to room temperature.
Hence recrystallization is preferred over solvent extraction when the desired compound is poorly soluble in the solvent pair at low temperatures and greatly soluble in the solvent pair at high temperatures.
Answer: Option (c) is the correct answer.
Explanation:
A binary mixture is defined as the mixture which contains two components in the aqueous medium. The two components are solute and solvent.
And, volatility is defined as the ability of a liquid solution or substance to readily change into vapors.
For a binary solution the expression for relative volatility is as follows.
= 
where, 
= relative volatility of more volatile component i
= vapor-liquid equilibrium concentration of component i in the vapor phase
= vapor-liquid equilibrium concentration of component i in the liquid phase
= vapor-liquid equilibrium concentration of component j in the vapor phase
= vapor-liquid equilibrium concentration of component j in the liquid phase
So, when > 1 then separation by distillation is easier in nature.
Thus, we can conclude that in order to separate the components of a binary mixture, the relative volatility should be greater than unity.
