Answer:
No, ΔE does not always equal zero because it refers to the systems internal energy, which is affected by heat and work
Explanation:
According to the first law of thermodynamics, energy is neither created nor destroyed. This implies that the total energy of a system is always a constant.
So, according to the first law of thermodynamics we have that ΔE = q + w. This means that the value of ΔE depends on q (heat) and w(work). Hence ΔE is not always zero since it depends on the respective values of q and w.
K₃PO₄ → 3K⁺ (aq) + PO₄³⁻(aq)
One mole of PO₄³⁻ ion gets dissociated from one mole of K₃PO₄
As per the definition of Avogadro's number, 1 mole = 6.022 x 10²³ ions
One mole of PO₄³⁻ ions x (6.022 x 10²³ ions/ 1 mole of PO₄³⁻ ions )
= 6.022 x 10²³ ions
Therefore , there are 6.022 x 10²³ PO₄³⁻ ions in a mole of K₃PO₄.
Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.
In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.
