Enthalpy of combustion of ethyl alcohol, c2 h5 oh, is – 950 kj mol–1. how much heat is evolved when one gram of ethyl alcohol burns?

20.62 Kilo-joules

Molar mass of ethyl ethanol = 46.08 g/mol

Therefore;

46.08 g of  C₂H₅OH evolves heat equivalent to 950 kilojoules

We can calculate the amount of heat evolved by 1 g of C₂H₅OH

Heat evolved by 1 g of C₂H₅OH  = Molar enthalpy of combustion ÷ Molar mass

                                      = 950 kJ/mol ÷ 46.08 g/mol

                                      = 20.62 Kj/g

Therefore, a gram of C₂H₅OH  will evolve 20.62 kilo-joules of heat

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.