Answer:
0.1 M
<h3>
Explanation:</h3>
- Molarity refers to the concentration of a solution in moles per liter.
- It is calculated by dividing the number of moles of solute by the volume of solvent;
- Molarity = Moles of the solute ÷ Volume of the solvent
<u>In this case, we are given;</u>
- Number of moles of the solute, NH₄Cl as 0.42 moles
- Volume of the solvent, water as 4200 mL or 4.2 L
Therefore;
Molarity = 0.42 moles ÷ 4.2 L
= 0.1 mol/L or 0.1 M
Thus, the molarity of the solution will be 0.1 M
To find the moles, you can use the following formula
moles= Molarity x Liters
Molarity= 2.0 M
Liters= 0.0010 Liters ---------------->>>>>>>>>> 1.0 mL= 0.0010 Liters
moles= 2.0 M x 0.0010 Liters= 0.0020 moles
<u>Answer:</u> The
for the reaction is 72 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction follows:

The intermediate balanced chemical reaction are:
(1)

(2)
( × 2)
(3)
( × 2)
The expression for enthalpy of the reaction follows:
![\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[2\times (-\Delta H_2)]+[2\times (\Delta H_3)]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B1%5Ctimes%20%28%5CDelta%20H_1%29%5D%2B%5B2%5Ctimes%20%28-%5CDelta%20H_2%29%5D%2B%5B2%5Ctimes%20%28%5CDelta%20H_3%29%5D)
Putting values in above equation, we get:
![\Delta H^o_{rxn}=[(1\times (-1184))+(2\times -(-234))+(2\times (394))]=72kJ](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B%281%5Ctimes%20%28-1184%29%29%2B%282%5Ctimes%20-%28-234%29%29%2B%282%5Ctimes%20%28394%29%29%5D%3D72kJ)
Hence, the
for the reaction is 72 kJ.
It is a metal
hope it helps