Answer:

Explanation:
Assume the reaction is the combustion of propane.
Word equation: propane plus oxygen produces carbon dioxide and water
Chemical eqn: C₃H₈(g) + O₂(g) ⟶ CO₂(g) + H₂O(g)
Balanced eqn: C₃H₈(g) + 5O₂(g) ⟶ 3CO₂(g) + 4H₂O(g)
(a) Table of enthalpies of formation of reactants and products

(b)Total enthalpies of reactants and products

ΔᵣH° is negative, so the reaction is exothermic.
Fossil fuels is the answer
Photosynthesis requires energy, making it an endothermic reaction. Light, generally sunlight, is the source of this energy. The process converts the sun’s electromagnetic energy into chemical energy, which is then stored in chemical bonds in the plant. Sunlight is the primary source of energy on the surface of Earth.
The time take by Neptune to travel once around the Sun is called the orbital period. It takes Neptune about 165 Earth years to make one complete orbit around the Sun.
Use Boyle's Law of Pressure: P1 x V1 = P2 x V2. Givens: P1=0.9 atm V1= 4 P2= 0.9 atm Find: V2 Equation: 0.9 atm x 4 x 4 L = 0.20 atm x V2Solve: 36 atmL= 0.20 atm x V2 18 : = V2 Short answer: The new volume is 104 ml.