The standard heat of formation is the energy change that occurs when 1 mole of a substance is made from its elements in their standard states ( most stable form of the element at 1 bar of pressure and the specified temperature, usually 298 K or 25 degrees Celcius)
E.g for MgCO3
Mg (s) + C (s) + 3/2 O2 (g) = MgCO3
The pH is calculated using the expression: pH = - log [H3O+].
To find the concentration of [H3O+]
[H3O+] = 10^(-pH)
Solving the RHS we have 10^(-4.240) = 0.1440
Hence the concentration of H3O+ is 0.1440.
Rate of effusion gas/rate of effusion H2 = √(M(H2))/√(M(gas))
0.344= √2/√(M(gas))
√(M(gas))= √2/0.344
M(gas)= (√2/0.344)² =2/(0.344)² ≈16.9
First, let us calculate the moles of solute or sodium
bicarbonate is in the 1 ml solution.
<span>moles = 1 mL * (1 g
/ 9 mL) = 0.11 moles</span>
The molar mass of sodium bicarbonate is 84 g/mol,
therefore the mass is:
mass = 0.11 moles * 84 g/mol
<span>mass = 9.33 g</span>
The molar mass of the hydrate is 278.06
The molar mass of the anhydrous salt is 151.92
The molar mass of water in the hydrate is 126.14
