Answer : To calculate the standard molar enthalpy of complete combustion of liquid ethanol can be done by using the formula given below;

Now, the enthalpies of the elements in their standard state is zero always.
So the

Here we can avoid the heat of enthalpy of oxygen,carbon dioxide and water as they exists in their standard states.
So the

=
Answer:
By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers.
Explanation:
Sorry only knew the answer to the first question
Answer:
THE HEAT NEEDED TO CHANGE 3KG OF WATER FROM 10 C TO 80 C IS 877.8kJ OR 877,800 J.
Explanation:
Mass = 3.0 kg = 3 * 1000 = 3000 g
Initial temperature = 10 C
Final temperature = 80 C
Change in temperature = 80 - 10 = 70 C
Specific heat of water = 4.18 J/g C
Heat needed = unknown
Heat is the amount of energy in joules needed to change a gram of water by 1 C.
Heat = mass * specific heat * change in temperature
Heat = 3000 g * 4.18 J/g C * 70 C
Heat = 877 800 Joules
Heat = 877.8 kJ.
The heat needed to change 3 kg mass of water from 10 C to 80 C is 877,800 J or 877.8 kJ.
From the data obtained from the tests, the actual boiling point lies between 34°C and 40°C.
The boiling point of a substance is the temperature at which the pressure of the substance becomes equal to atmospheric pressure. Pure substances have a sharp boiling point while impure substances boil over a temperature range.
In this case, the boiling point of the substance after 10 tests is obtained as 37+/−3°C. This implies that the actual boiling point lies between 34°C and 40°C.
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