Answer:
-3108 kJ
Explanation:
Because the combustion is releasing heat, the reaction is exothermic, and because of that, the value of the enthalpy must be negative. When a reaction absorbs heat it is endothermic and the enthalpy is positive.
By the reaction given, there are 2 moles of C₂H₆ reacting. The molar mass of the compound is:
2* 12 g/mol of C + 6* 1 g/mol of H = 30 g/mol
So, 2 moles have 60 g (2mol * 30g/mol).
5.00 g --------------- -259 kJ
60 g --------------- δh
By a simple direct three rule:
5δh = -15540
δh = -3108 kJ
Answer:
Atom's chemical properties are determined by the number of electrons in its outermost shells.
Based on the number of electrons in the shells, it decides the reactivity of atoms.
Atoms with same number of electrons in the outer shells have similar chemical properties.
If atoms have 1,2 or 3 valence electrons they react by giving out those electrons to become stable. If atoms have 6 or 7 electrons in the outer shell they react by taking in electrons to complete its outer shell.
It has 9 protons, 9 electrons and 10 neutrons.
Answer:
Formula is NA2SO4•10H2O
Sodium sulfate decahydrate.
Explanation:
Sodium sulfate is soluble in water. Soduim sulphare form various hydrates, so if the solution is open to the atmosphere for a week at least a lot of the water will have evaporated leaving behind a solid hydrate of Soduim sulfate.
Mass of anhydrous Na2SO4 = molar mass * number of moles
Molar mass = (23*2) + (32*1) + (16*4)
= 146 g/mol
Mass = 146*1
= 146 g of NA2SO4
NA2SO4•nH2O --> Na2SO4 + nH2O
Molar mass of hydrate, NA2SO4.nH2O
= (142 + 18n) g/mol
Mass of NA2SO4.nH2O = (142 + 18n)*1
= (142 + 18n) g
Mass of the residue = 322.2 g
Therefore, 142 + 18n = 322.2
18n = 180.2
n = 10
Formula is NA2SO4•10H2O
Sodium sulfate decahydrate.
0.0588 mol MgSO4 / 0.0588 = 1 mol MgSO4
0.412 mol H2O / 0.0588 = 7 mol H2O
Formula is MgSO4•7H2O
Oxygen cannot be broken down into a simpler substance by using chemicals :) Hope this helps and the other answer gets removed :)