Germanium forms a substitutional solid solution with silicon. Compute the weight percent of germanium that must be added to silicon to yield an alloy that contains 3.43 × 1021 Ge atoms per cubic centimeter. The densities of pure Ge and Si are 5.32 and 2.33 g/cm3, respectively. The atomic weights for germanium and silicon are 72.64 and 28.09 g/mol, respectively.

The answer to tnhe question is;

The weight percent of germanium to be added is 16.146 %.

Explanation:

To solve the question, we note that  the formula to calculate the weight percent of an element in terms of the number of atoms per cm³ in a 2 element alloy is given by,

Where

N = Avogadro's Number

ρ₁ = Density of alloy whose weight percent is sought

ρ₂ = density of the other alloy

N₁ = Number of atoms per cubic centimeter

A₁ = Atomic weight of the element whose weight percent is sought

Therefore

= 16.146 %.

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.