The above question is incomplete, here is the complete question:
Calculate the standard molar enthalpy of formation of NO(g) from the following data at 298 K:


Answer:
The standard molar enthalpy of formation of NO is 90.25 kJ/mol.
Explanation:


To calculate the standard molar enthalpy of formation
...[3]
Using 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.
[1] - [2] = [3]


![\Delta H^o_{3}=66.4 kJ - [ -114.1 kJ] = 180.5 kJ](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7B3%7D%3D66.4%20kJ%20-%20%5B%20-114.1%20kJ%5D%20%3D%20180.5%20kJ)
According to reaction [3], 1 mole of nitrogen gas and 1 mole of oxygen gas gives 2 mole of nitrogen monoxide, So, the standard molar enthalpy of formation of 1 mole of NO gas :
=

Physical Properties<span>: </span>Physical properties<span> can be observed or measured without changing the composition of matter. </span>Physical properties<span> are used to observe and describe matter. so physical changes are the change in temperature of the land and the evaporation of water and change humidity of the air. chemical change is the ripening of the orange</span>
1. solute is the substance that is being dissolve,while solvent is dissolving medium
2.saturated is solution that contain maximum amount of solut that capable of being dissolve and supersaturated is solution that contain less amount or medium of solut that capable being dissolve : example vinger
3. is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2 H2, and two molecules of water would be written 2 H2O . yes it's can be change only in caseWhen you balance an equation you can only change the coefficients
#1
<span>The rate of diffusion of a gas is inversely proportional to the square root of its molecular weight.
#2
shape, molecular weight. I don't know for sure though
#3
</span>O2, N2, Ar, H2O vapor
Answer:
is the density of solid calcium.
Explanation:
Formula used :

where,
= density
Z = number of atom in unit cell
M = atomic mass
= Avogadro's number
a = edge length of unit cell
We have:
r = 197 pm = 



M = 40 g/mol
Z = 4
On substituting all the given values , we will get the value of 'a'.


is the density of solid calcium.