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:
Cutting, tearing, shattering, grinding, and mixing are further types of physical changes because they change the form but not the composition of a material. For example, mixing salt and pepper creates a new substance without changing the chemical makeup of either component.
Explanation:
I did some fire simulation work recently where a small paper fire (think like half a ream of printer paper) was putting out 4000 watts, or about 5 horsepower. A large roaring campfire is going to be a few multiples of that depending on size, of course.
The correct analogy is that of "A big greedy dog stealing away a bone from a smaller dog."
An ionic bond is a bond formed formed between a metallic atom and a non-metallic atom.
The metallic atom is electropositive while the non-metallic atom is electronegative. Therefore, the metallic atom donates or gives up its electrons to the non-metallic atom which accepts the electrons.
During the formation of chemical bonds, only valence or outermost shell electrons are involved.
Metallic atoms have few valence electrons (between 1 to 3 electrons) while non-metallic atoms have many valence electrons (between 5 to 7 electrons).
Therefore the analogy by the student of a big greedy dog stealing away a bone from a smaller dog is correct because the non-metallic atoms takes the few electrons of the metallic atom and add to the many electrons they already have during the formation of an ionic bond.
Learn more about an ionic bond at: brainly.com/question/1225796
Answer:
atoms are too small to be seen under a microscope
Explanation:
scientists have been always making research on atomic structure which cannot be directly looked through a microscope