A35.6 g sample of ethanol (c2h5oh) is burned in a bomb calorimeter, according to the following reaction. if the temperature rose from 35.0 to 76.0°c and the heat capacity of the calorimeter is 23.3 kj/°c, what is the value of (change in enthalpy of reaction) dh°rxn ? the molar mass of ethanol is 46.07 g/mol.

Answer is: -1.24 x 103 kJ/mol the
The answer is right above so don't worry about reading all these.

reason why The heat capacity of the calorimeter is
c
=
23.3

k
J
/
o
C
,

and the change in temperature during the reaction is
Δ
T
=
76.0
−
35.0
o
C
=
41
o
C
.

The heat change during this combustion is:

Q
=
c
Δ
T
=
(
23.3

k
J
/
o
C
)
(
41
o
C
)
=
955.3

k
J
.

We burned 35.6 g of ethanol, whose molar mass is given as 46.07 g/mol. How many moles are these? We evaluate:

35.6

g
46.07

g
/
m
o
l
=
0.733

m
o
l
.

The enthalpy of reaction is therefore:

Δ
H
=
955.3

k
J
0.773

m
o
l
=
1236

k
J
/
m
o
l
.

Since this is an exothermic (heat-releasing) reaction, we conventionally introduce a negative sign and write:

Picture and explanation: C2H5OH(l) + O2(g) --> CO2(g) + H2O(g) ?H_ rxn = ?

-1.24 * 103 kJ/mol

+1.24 * 103 kJ/mol

-8.09 * 103 kJ/mol

-9.55 * 103 kJ/mol

+9.55 * 103 kJ/mol

Things you need to know: Enthalpy of Reaction
The enthalpy of a chemical reaction is the amount of heat released or absorbed when the reactants' bonds are broken and the products' bonds are formed. Exothermic reactions give off heat and are assigned a negative sign by convention, while endothermic ones absorb heat are carry a positive

It’s the energy source of stars