After 3 half life periods you would have 5 grams of krypton left because half of 40 is 20 half of 20 is 10 and half of 10 is 5
Answer : Option A) Molecules are speeding up during boiling.
Explanation : As shown in the above image it is clearly observed that the molecules are been transformed from liquid to gaseous state. Which means that the intermolecular distance between the molecules is increasing as they are boiling and getting transformed into gaseous form. They are speeding up to form gas from liquid state and achieve stability as the heat is supplied in greater amount. Boiling of liquid is causing the liquid molecules to speed up and get transformed into gaseous molecules.
6.8 is the pH of the solution after 10 ml of 5M NaOH is added.
Explanation:
Data given:
Molarity of C6H5CCOH = 0.100 M
molarity of ca(c6h5coo)2 = 0.2 M
Ka = 6.3 x 10^-5
first pH is calculated of the buffer solution
pH = pKa+ log 10 ![\frac{[A-]}{[HA]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BA-%5D%7D%7B%5BHA%5D%7D)
pKa = -log10[Ka]
pka = -log[6.3 x10^-5]
pKa = 4.200
putting the values to know pH of the buffer
pH = 4.200 + log 10 
pH = 4.200 + 0.3
pH = 4.5 (when NaOH was not added, this is pH of buffer solution)
now the molarity of the solution is calculated after NaOH i.e Mbuffer is added
MbufferVbuffer = Mbase Vbase
putting the values in above equation:
Mbuffer = 
= 
= 0.01 M
molarity or [ A-] = 5M
pH = pKa+ log 10
pH = 4.200 + log 10 
pH = 4.200+ 2.69
pH = 6.8
Answer:
The acronym is used to remember evidence of a chemical change.
Explanation:
P=precipitate
U=unexpected color change
F=fizzing
A=aroma
R=replaced by a new substance
T= temperature change
Nitric acid is HNO3 while Calcium Hydroxide is a base with a chemical formula Ca(OH)2. When acid reacts with base, it forms salt and water (H20). Hence forming the equation HNO3 + Ca(OH)2 -> Ca(NO3)2 + H20.
To gain the same number of atoms on both sides, the balanced molecular equation should be:
2NO3 + Ca(OH)2 -> Ca(NO3)2 + 2H2O
with: 4 Hydrogen, 2 Nitrogen, 8 Oxygen, and 1 Calcium
