The given question is incomplete. The complete question is:
How much heat is produced when 24.8 g of 
is burned in excess oxygen gas
Given: 
ΔH= −802 kJ.
Answer: 1243.1 kJ
Explanation:
Heat of combustion is the amount of heat released on complete combustion of 1 mole of substance.
Given :
Amount of heat released on combustion of 1 mole of methane = 802 kJ kJ/mol
According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number 
of particles.
1 mole of weighs = 16 g
Thus we can say:
16 g of on combustion releases heat = 802 kJ
Thus 24.8 g of on combustion releases =
Thus heat released when 24.8 g of methane is burned in excess oxygen gas is 1243.1 kJ
Answer:
First
divide each element by its Molecular Mass to get their respective moles
Then Divide through by the lowest of the moles
You'll have the ratio of Carbon Hydrogen and Oxygen to be
C2H3O
Given Molecular Mass=184.27
C2H3On=184.27
n(12x2 + 1x3 + 16) =184.27
Evaluating this... You'll have n=4.3
Pls check if you assigned the correct value to each element
The toxic gar expelled from the reaction between gasoline and oxygen in the vehicle's engine is both Carbon dioxide and monoxide
Consequences of oxygenation. Eventually, oxygen started to accumulate in the atmosphere, with two major consequences. Oxygen likely oxidized atmospheric methane (a strong greenhouse gas) to carbon dioxide (a weaker one) and water.
Answer: B= Rusting ability
Explanation:
Physical property is defined as the property which can be measured and whose value describes the state of physical system. For Example: State, density etc.
Chemical property is defined as the property of a substance which is observed during a reaction where the chemical composition identity of the substance gets changed.
1. Boiling point: is a physical property as there is a change of state.
2. Rusting ability: is a chemical property as there is formation of new substances.
3. Melting point: is a physical property as there is a change of state.
4. Density: is a physical property as there is no formation of new substances.
