Answer:
- <u><em>It is positive when the bonds of the product store more energy than those of the reactants.</em></u>
Explanation:
The <em>standard enthalpy of formation</em>, <em>ΔHf</em>, is defined as the energy required to form 1 mole of a substance from its contituent elements under standard conditions of pressure and temperature.
Then, per defintion, when the elements are already at their standard states, there is not energy involved to form them from that very state; this is, the standard enthalpy of formation of the elements in their standard states is zero.
It is not zero for the compounds in its standard state, because energy should be released or absorbed to form the compounds from their consituent elements. Thus, the first choice is false.
When the bonds of the products store more energy than the those of the reactants, the difference is:
- ΔHf = ΔHf products - ΔHf reactants > 0, meaning that ΔHf is positive. Hence, the second statement is true.
Third is false because forming the compounds may require to use (absorb) or release (produce) energy, which means that ΔHf could be positive or negative.
Fourth statement is false, because the standard state of many elements is not liquid. For example, it is required to supply energy to iron to make it liquid. Thus, the enthalpy of formation of iron in liquid state is not zero.
. 1s2 2s2 2p6 3s2 3p6 3d10 One point is earned for the correct configuration.
Answer: The charge on the plates are 88.4 picafarad
Explanation:The equation used in measuring charge in a plate is given as:
C=Q/V =E A/D
Where E= dielectric content
A= Area of plates
d= distance between plates
Using dielectric constant for Air=8.84×10-12F/m
A=100cm2=0.01m2
d=10mm=0.001m
C= 8.84×10-12×0.01/0.001
C= 88.4 picafarad
Answer:
What happens if the solvent-solute attraction is greater than the solute-solute attraction when two substances are mixed? The solute particles are pulled apart and dispersed throughout the particles of the solvent, which holds the particles of the solute in solution.
Explanation:
2Fe + Cl₂ -> 2FeCl
4Fe + 3O₂ -> 2Fe₂O₃
