A 25.0-mL sample of a 1.20 M potassium chloride solution is mixed with 15.0 mL of a 0.900 M lead(II) nitrate solution and this p

Answer:

A total of 2667 tires are required to satisfy the annual power needs of ten homes.

Explanation:

According to the Second Law of Thermodynamics, not all energy produced when tires are incinerated can be effectively used due to losses associated with finite temperature differences. The energy obtainable from a tire when burned, measured in kilowatt-hours (), can be calculated using the efficiency definition:

Where:

- Efficiency, which is dimensionless.

- Energy released from burning, measured in kilowatt-hours.

Taking into account and , the yearly energy yield from a tire amounts to:

Thus, the number of tires necessary to meet the electricity demand of ten homes for one year is:

A total of 2667 tires are necessary to satisfy the annual power needs of ten homes.

Answer:

             Protons: 19

             Neutrons: 25

             Electrons: 19

Explanation:

Protons:

                   The atomic number determines the number of protons in an atom. Consequently, with Potassium's atomic number being 19, it contains 19 protons.

Neutrons:

                   The formula to find neutrons is:

                           # of Neutrons  =  Atomic Mass - # of Protons

Given:

                                Atomic Mass  =  43

                                # of Protons  =  19

Thus,

                                # of Neutrons  =  43 - 19

                                # of Neutrons  =  24

Electrons:

                                   In a neutral atom, the quantity of electrons matches that of protons. Therefore, a neutral Potassium atom with 19 protons must equally have 19 electrons.

Response: Option A) The lattice energy rises as cations become smaller, as demonstrated by LiF and KF.

Clarification: It has been observed that the lattice energy is largely determined by two primary factors regarding ionic solids:

i) The ionic charges - An increase in the charge of the ions corresponds to an increase in lattice energy.

and

ii) The size or radius of the ions - As the ionic size grows, the lattice energy diminishes accordingly.

Therefore, in this context, the latter factor is evident. Thus, it can be concluded that as cation sizes decrease among ionic solids, the lattice energy increases.

Result: The count of bonding electrons and non-bonding electrons amounts to (4, 18).

Explanation:

The Lewis-dot structure reveals the number of bonding and non-bonding electrons in .

Lewis-dot representation: It illustrates the valence electron count for atoms in a molecule and shows how they bond, as well as any lone pairs of electrons.

In this structure, 'Xe' is the central atom while 'F' is the terminal atom.

Xenon comprises 8 valence electrons, whereas fluorine contains 7.

The total number of valence electrons in is calculated as 8 + 2(7) = 22 electrons

From the Lewis-dot structure, we can determine

The count of electrons involved in bonding = 4

The count of electrons involved in non-bonding (lone-pairs) = 22 - 4 = 18

Thus, the bonding and non-bonding electron counts are (4, 18).

Below is the Lewis-dot structure for .

Answer:

In all listed reactions, ΔH°rxn does not correspond to the ΔH°f of the resulting product.

Explanation:

The standard enthalpy of formation (ΔH°f) signifies the enthalpy change that occurs when 1 mole of a product is created from its basic elements in their standard states.

1/2 O₂(g) + H₂O(g) ⟶ H₂O₂(g)

ΔH°rxn does not equal ΔH°f of the product, since H₂O(g) is a compound rather than an element.

Na⁺(g) + F⁻(g) ⟶ NaF(s)

ΔH°rxn is not the same as ΔH°f of the product because Na and F are not in their standard states (Na(s); F₂(g)).

K(g) + 1/2 Cl₂(g) ⟶ KCl(s)

ΔH°rxn is not equal to ΔH°f of the product due to K being outside its standard state (K(s)).

O₂(g) + 2 N₂(g) ⟶ 2 N₂O(g)

ΔH°rxn does not match ΔH°f of the product as 2 moles of N₂O are produced.

In none of the above cases does ΔHrxn match ΔHf of the product.