The reaction is combination of hydrogen molecules and oxygen molecules and form water. So the oxygen and hydrogen required together is equal to the mass of the water formed.
The mass number is defined as the total number of protons and neutrons in an atom.
I would say copper, silver, and tin, since an alloy is a mixture of metals and metalloids.
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]
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 :
=