The mass change, or the mass defect, can be calculated by the formula that is very known to be associated with Albert Einstein.
E = Δmc²
where
E is the energy gained or released during the reaction
c is the speed of light equal to 3×10⁸ m/s
Δm is the mass change
(1.715×10³ kJ)(1,000 J/1 kJ) = Δm(3×10⁸ m/s)²
Δm = 1.91×10⁻¹¹ kg
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
<u>Answer:</u> The temperature at which the food will cook is 219.14°C
<u>Explanation:</u>
To calculate the final temperature of the system, we use the equation given by Gay-Lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.
Mathematically,

where,
are the initial pressure and temperature of the gas.
are the final pressure and temperature of the gas.
We are given:

Putting values in above equation, we get:

Converting the temperature from kelvins to degree Celsius, by using the conversion factor:


Hence, the temperature at which the food will cook is 219.14°C
When the Pka for formic acid = 3.77
and Pka = -㏒ Ka
3.77 = -㏒ Ka
∴Ka = 1.7x10^-4
when Ka = [H+][HCOO-}/[HCOOH]
when we have Ka = 1.7x10^-4 &[HCOOH] = 0.21 m
so by substitution: by using ICE table value
1.7x10^-4 = X*X / (0.21-X)
(1.7x10^-4)*(0.21-X) = X^2 by solving this equation for X
∴X = 0.0059
∴[H+] = 0.0059
∴PH= -㏒ [H+]
= -㏒ 0.0059
= 2.23
Answer:
pH = 7.08
Explanation:
HCl ---------> H^+ + Cl^-
It's an acid, we are using this formula
pH = -log [H]^+
H^+ = 8.4 * 10^-8
pH = - log [8.4 * 10^-8]
It can also be solved as
-log 8.4-(-8log 10)
-0.924-(-8×1)
-0.924+8
7.076
To the nearest hundredth
pH = 7.08