Answer:
Mass of sodium chloride decomposed = 24.54 g
Explanation:
Given data:
Mass of sodium chloride decomposed = ?
Mass of chlorine gas formed = 15 g
Solution:
Chemical equation:
2NaCl → 2Na + Cl₂
Number of moles of Cl₂:
Number of moles = mass/molar mass
Number of moles = 15 g/ 71 g/mol
Number of moles = 0.21 mol
Now we will compare the moles of Cl₂ with NaCl from balance chemical equation.
Cl₂ : NaCl
1 : 2
0.21 : 2×0.21 = 0.42 mol
Mass of Sodium chloride decompose:
Mass = number of moles × molar mass
Mass = 0.42 mol × 58.44 g/mol
Mass = 24.54 g
Just look it up on goog^le or a chart
Answer:

Explanation:
Hello,
In this case, the enthalpy of combustion is understood as the energy released when one mole of fuel, in this case octene, is burned in the presence of oxygen and is computed with the enthalpies of formation of the fuel, carbon dioxide and water as shown below (oxygen is circumvented as it is a pure element):

Thus, since we already know the enthalpy of combustion of the fuel, for carbon and water we have -393.5 and -241.8 kJ/mol respectively, thereby, the enthalpy of combustion turns out:

Best regards.