Answer:
C.) HOCl Ka=3.5x10^-8
Explanation:
In order to a construct a buffer of pH= 7.0 we need to find the pKa values of all the acids given below
we Know that
pKa= -log(Ka)
therefore
A) pKa of HClO2 = -log(1.2 x 10^-2)
=1.9208
B) similarly PKa of HF= -log(7.2 x 1 0^-4)= 2.7644
C) pKa of HOCl= -log(3.5 x 1 0^-8)= 7.45
D) pKa of HCN = -log(4 x 1 0^-10)= 9.3979
If we consider the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution
The weak acid for making the buffer must have a pKa value near to the desired pH of the weak acid.
So, near to value, pH=7.0. , the only option is HOCl whose pKa value is 7.45.
Hence, HOCl will be chosen for buffer construction.
Answer: The vapor pressure of the solution at is 137 torr
Explanation:
As the relative lowering of vapor pressure is directly proportional to the amount of dissolved solute.
The formula for relative lowering of vapor pressure will be,
where,
= relative lowering in vapor pressure
i = Van'T Hoff factor = 1 (for non electrolytes)
= mole fraction of solute =
Given : 13.06 g of napthalene is present in 100 g of solution, thus (100-13.06) g = 86.94 g of hexane
moles of solute (napthalene) =
moles of solvent (hexane) =
Total moles = moles of solute (napthalene) + moles of solvent (hexane) = 0.102 + 1.01 = 1.112
= mole fraction of solute (napthalene) =
Thus the vapor pressure of the solution at is 137 torr
Answer:
No
Explanation:
A chemical change is a change that involves a change in the chemical composition of matter. A new substance is formed. In a chemical change, new chemical and physical properties of the substance are formed. In a chemical change, the chemical and physical properties of the substance formed will be different from the original substance.
<span> are composed of the fragments, or CLASTS. If PRE-existing </span>minerals<span> and rock. A </span>clast<span> is a fragment of </span>geological detritus,<span>chunks and smaller grains of rock broken off other rocks by </span>physical weathering.[2]<span> Geologists use the term CLASTIC </span><span>with reference to </span>sedimentary rocks<span> as well as to particles in </span>sediment transport<span> whether in </span>suspension<span> or as </span>bed load<span>, and in </span>sediment<span> deposits.</span>
Answer:
Explanation:
Materials are clothes and heavy rope