Answer:
C. Covalent Bond
Explanation:
A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
Answer:
Concentration of OH⁻:
1.0 × 10⁻⁹ M.
Explanation:
The following equilibrium goes on in aqueous solutions:
.
The equilibrium constant for this reaction is called the self-ionization constant of water:
.
Note that water isn't part of this constant.
The value of
at 25 °C is
. How to memorize this value?
- The pH of pure water at 25 °C is 7.
![[\text{H}^{+}] = 10^{-\text{pH}} = 10^{-7}\;\text{mol}\cdot\text{dm}^{-3}](https://tex.z-dn.net/?f=%5B%5Ctext%7BH%7D%5E%7B%2B%7D%5D%20%3D%2010%5E%7B-%5Ctext%7BpH%7D%7D%20%3D%2010%5E%7B-7%7D%5C%3B%5Ctext%7Bmol%7D%5Ccdot%5Ctext%7Bdm%7D%5E%7B-3%7D)
- However,
for pure water. - As a result,
at 25 °C.
Back to this question.
is given. 25 °C implies that
. As a result,
.
Answer:
20.468 kilo Joules is the enthalpy change when one mole of sodium nitrate dissolves.
Explanation:
Heat lost by solution ad calorimeter = Q
Heat capacity of solution ad calorimeter = C = 1071 J/°C
Change in temperature = ΔT = 21.56°C - 25.00°C = -3.44°C


Heat gained by sodium nitrate = -Q = -(-3,684.24 J)=3,684.24 J
Moles of sodium nitrate = 
When 0.18 mole of sodium nitrate was dissolved in water 3,684.24 joulesof heat was absorbed by it.
Then heat absorbed by 1 mole of sodium nitrate :

1 J = 0.001 kJ
20.468 kilo Joules is the enthalpy change when one mole of sodium nitrate dissolves.