Study the reactions. C2H2 (g)+2H2 (g)→C2H6 (g)ΔH=−75 kcal
C2H4 (g)+H2 (g)→C2H6 (g)ΔH=−33 kcal
C2H2 (g)+H2 (g)→C2H4 (g)ΔH= ?

How can the enthalpy of Reaction III be calculated correctly?

A) by first multiplying the enthalpy of Reaction 2 by two and then finding the sum of the enthalpy of Reaction 1 and the enthalpy of Reaction 2

B) by first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of Reaction 2
C) by adding the enthalpy of Reaction 1 and the enthalpy of Reaction 2
D) by subtracting the enthalpy of Reaction 1 from the enthalpy of Reaction 2

chemical energy is stored in the chemical bonds of atoms and molecules. it can only be seen when it is released in a chemical reaction. when chemical energy is released, the substance from which the energy came is often changed into an entirely different substance.

this chemical reaction releases energy in the form of light and heat. chemical energy is the potential energy stored in the arrangement of atoms within molecules. breaking chemical bonds requires energy, while forming new chemical bonds releases energy.

the atp molecule can store energy in the form of a high energy phosphate bond joining the terminal phosphate group to the rest of the molecule. in this form,energy can be stored at one location, then moved from one part of the cell to another, where it can be released to drive other biochemical reactions.

the answer is 1 i believe

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.