M₁=6.584 g
m₂=4,194 g
m(H₂O)=m₁-m₂
w(H₂O)=m(H₂O)/m₁
w(H₂O)=(m₁-m₂)/m₁
w(H₂O)=(6.584-4.194)/6.584=0.3630 (36.30%)
the percentage by mass of water in the hydrate 36.30
The protons! Is it the answer
Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Explanation:
Temperature of Solid
Melting temperature of Solid 
Temperature of liquid 
Specific heats of solid ethanol = 0.97 J/gK
Specific heats of liquid ethanol = 2.3 J/gK
Heat required to melt the the 25 g solid
at 159 K
= 159 K - 138 K = 21 K

Heat required to melt and raise the temperature of
upto 223 K
= 223 K - 159 K = 64 K

Total heat to convert solid ethanol to liquid ethanol at given temperature :
(1kJ=1000J)
Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Answer:
The pH of the sweater containing Hydrogen ion concentration
is
<u>8</u>
<u></u>
Explanation:
pH = It is the negative logarithm of activity (concentration) of hydrogen ions.
pH = -log([H+])
Now, In the question the concentration of [H+] ions is :
![[H^{+}]=1\times 10^{-8}](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%3D1%5Ctimes%2010%5E%7B-8%7D)

use the relation:


pH = 8
Note : <em><u> 1 times 10 to the power of 8 must be" 1 times 10 to the power of -8"</u></em>
If the concentration is
![[H^{+}]=1\times 10^{8}](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%3D1%5Ctimes%2010%5E%7B8%7D)
Then pH = -8 , which is not possible . So in that case the pH calculation is by other method
Answer:
The goal of Science is to expand knowledge.
Explanation: