<u>Answer:</u> The formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
Given mass of oxygen gas = 83 g
Molar mass of oxygen gas = 32 g/mol
Putting values in above equation, we get:
For the given chemical equation:
<u>Sign convention of heat:</u>
When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.
By Stoichiometry of the reaction:
When 3 moles of oxygen gas is formed, the amount of heat absorbed is 824.2 kJ
So, when 2.594 moles of oxygen gas is formed, the amount of heat absorbed will be = 
Hence, the formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.
Answer:
80 MOLES OF WATER ARE PRODUCED WHEN 20 MOLES OF PROPANE ARE BURNED IN EXCESS OXYGEN ON A GAS GRILL.
Explanation:
Equation for the reaction:
C3H8 + 5 O2 ---------> 4 H2O + 3 CO2 + Heat
The above equation is in the presence of excess oxygen.
In this reaction,
1 mole of propane forms 4 moles of H2O
If 20 moles of propane were to be used, how many moles of water will be produced?
1 mole of propane = 4 moles of water
20 moles of propane = ( 4 * 20 ) moles of water
= 80 moles of water.
So, if 20 moles of propane were burned in excess oxygen, 80 moles of water will be formed. Propane is heavier than air and when properly combusted produces a large amount of heat. It is also non toxic.
C ........................
A liquid boils when it's vapor pressure will be equal to the atmospheric pressure. With the lid on, increases the pressure inside the pot. As an effect, it would take a higher temperature to reach the boiling temperature.
Answer: The boiling point will be raised. <span />
The technique which is used to purify the chemicals is said to be recrystallization.
In this process, solute is dissolved in a particular solvent and according to its principle, the quantity of solute which is dissolved by solvent increases with increase in temperature. The solutes are more soluble at high temperatures in comparison to room temperature (insoluble) or low temperature. Therefore, heating is needed to dissolve the solute in the solvent.
Now, in the case of hexane or diethyl ether, flameless heating is required because of their low boiling points implies if they heat directly on fire, then they have tendency to catch fire. Thus, hexane and diethyl ether are highly flammable.
