Answer:
The approximate molar enthalpy of combustion of this substance is -66 kJ/mole.
Explanation:
First we have to calculate the heat gained by the calorimeter.

where,
q = Heat gained = ?
c = Specific heat = 
ΔT = The change in temperature = 3.08°C
Now put all the given values in the above formula, we get:


Now we have to calculate molar enthalpy of combustion of this substance :

where,
= enthalpy change = ?
q = heat gained = 8.2544kJ
n = number of moles methane = 

Therefore, the approximate molar enthalpy of combustion of this substance is -66 kJ/mole.
Answer:
Explanation:
C + O2 → CO2
Mole of C = 24 g/(12 g/mole)
Mole of C = 2 mole
Mole of molecular O2 = 74 g/(32 g/mole)
Mole of molecular O2 = 2.3125 mole
Since mole of C < mole of O2, then C being the limiting reagent.
From the reaction, it shows that mole ratio between C and O2 = 1 : 1.
So, 2 moles of C will stoichiometrically react with 2 moles of O2 to generate 2 moles of CO2.
Avogadro's law states that :"equal volumes of all gases, at the same temperature and pressure, have the same number of molecules i.e. 6.02 x 10^23 molecules/mole.
Therefore, 2 moles of CO2 contain 2 moles x 6.02 x 10^23 molecules/mole = 1.204 x 10^24 molecules of CO2 is formed.
The answer is letter C.
Because we classify something as a star when it is: a large ball of gas that undergoes nuclear fusion. Given this definition, a comet is not a star. A comet is a ball of ice and dirt hurtling through space, it shines only because it reflects ligh
Answer:
b. independent/manipulated variable
Explanation:
Independent/manipulated variable - refers to the variable that is changed by the scientist or an experimenter. Only one variable that is independent is required to ensure a fair test in an excellent experiment. As the independent variable is being changed by an experimenter or scientist, data is being recorded simultaneously as they are collected.
When you transferred the hot metal from the boiling water and into the calorimeter, The effect will be
- Change in temp is positive
- Temp of metal V, dT=-ve
- No change occurs in the specific heat of metal
This is further explained below.
<h3>What is the Specific heat of the metal?</h3>
a )Since the metal of the cup is hot and the water inside is cold, the water's temperature will rise as heat is transferred from the metal to the liquid.
Change in temp is positive
b)
Due to (a), heat is lost from the food to the water in the cup, lowering the metal's temperature.
Temp of metal V, dT=-ve
c)
No change occurs in the specific heat of metal because of its constant property.
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