Answer: 
Explanation: <u>Heats</u> <u>of</u> <u>formation</u> is the amount of heat necessary to create 1 mol of a compound from its molecular constituents. The basic conditions the substance is formed is at standard conditions: 1 atm and 25°C. Each compound has its own heat of formation per mol of compound (kJ/mol), but to an element is assigned a value of zero.
<u>Standard</u> <u>Enthalpy</u> <u>Change</u> is defined as the heat absorbed or released when a reaction takes place. It can be positive or negative, which means reaction is endothermic or exothermic, respectively.
Enthalpy change is calculated as the difference between the sum of heat formation of products and the sum of heat formation of the reactants:

For the reaction
2NH₃ + 3N₂O → 4N₂ + 3H₂O
2(-46.2) + 3(82.05) 4(0) + 3(-241.8)
![\Delta H^{0}=3(-241.8)-[ 2(-46.2)+3(82.05)]](https://tex.z-dn.net/?f=%5CDelta%20H%5E%7B0%7D%3D3%28-241.8%29-%5B%202%28-46.2%29%2B3%2882.05%29%5D)


<u>The standard enthalpy change for the reaction is </u>
<u> kJ</u>
Answer:
Approximately
.
Explanation:
Convert both volumes to standard units (that is: liters.)
.
.
Number of moles of
initially present (in the
solution at
.)
.
Number of moles of
from the titration:
.
neutralizes
at a
ratio:
.
Hence,
.
.
Answer:
4.22
Explanation:
pH stands for potential hydrogen. The letter “p” denotes potential and the letter “H” denotes hydrogen.
pH helps to find the acidity or alkalinity of an aqueous solution.
The number of hydrogen ions (protons) present in a solution is determined by the pH scale.
A pH greater than 7 makes the water more alkaline and a pH less than 7 makes the water more acidic.
![pH=-\log [H^+]=-\log [0.00006]=4.22](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D%3D-%5Clog%20%5B0.00006%5D%3D4.22)
<span>C4H4
The compound in question has an equal ratio of hydrogen and carbon. The atomic weight of carbon is roughly 12 and the atomic weight of hydrogen is roughly 1. The mass of the compound in question is roughly 52.
52/13=4
C4H4</span>