Consider the following Figure 2 and two atoms that are initially an infinite distance apart, x =00, at which point the potential energy of the system is U = 0. If they are brought together to x = x, the potential energy is related to the total force P by dU dx = P Given this, qualitatively sketch the variation of U with x. What happens at x=x? What is the significance of x = x, in terms of the potential energy? 0 P, Force 19 Attraction Total Repulsion x, Distance Figure 2. Variation with distance of the attractive, repulsive, and total forces between atoms. The slope dP/dx at the equilibrium spacing xe is proportional to the elastic modulus E; the stress σb, corresponding to the peak in total force, is the theoretical cohesive strength.

The first step in the preparation of lead from its ore (galena, PbS) consists of roasting the ore. PbS(s)+32O2(g)SO2(g)+PbO(s) Calculate the standard enthalpy change for this reaction, using enthalpies of formation (see Appendix C).

Two positively charged spheres, each with a charge of 2.0x 10-5 C, a mass of 1.0 kg, and separated by a distance of 1.0 cm, are held in place on a frictionless track. (a) What is the electrostatic potential energy of this system? (b) If the spheres are released, will they move toward or away from each other? (c) What speed will each sphere attain as the distance between the spheres approaches infinity?

Consider an electron and a proton that are separated by 230 pm. What is the electrostatic potential energy (in joules) between an electron and a proton that are separated by 230 pm? What is the change in potential energy if the distance separating the electron and proton is increased to 1.0 nm? Does the potential energy of the two particles increase or decrease when the distance is increased to 1.0 nm? Using the result in c, conclude what happens to the energy of the system if the distance separating two oppositely charged particles (such as electrons and nuclei in chemical bonds) is increased.

For each of the following processes, does the potential energyof the object(s) increase or decrease? (a) The distancebetween two oppositely charged particles is increased.(b) Water is pumped from ground level to the reservoir of awater tower 30 m above the ground. (c) The bond in a chlorinemolecule, Cl2, is broken to form two chlorine atoms.

(b) What is the first law of thermodynamic? Define the Hess law. Given the following data; 2CIF(g) + 0,(g) CI,0(g) + F,O(g) AH = 167.4 kJ AH = 341.4 kJ SH = -43,4 kJ 2CIF,(g) + 20,(g) → CĻ0(g) + 3F,O(g) 2F,(2) + O(8) → 2F,O(g) calculate AH for the reaction CIF(g) + F(8) CIF,(g)

Decide how the sketches below would be listed, if they were listed in order of decreasing potential energy. That is, select "1" beside the sketch that shows the system with the highest potential energy, select "2" beside the sketch that shows the system with the next highest potential energy, and so on. Note for advanced students: since the units of each charge are not written, you may assume any convenient and reasonable unit, for example coulombs or multiples of e. 國 EHE O1 (highest) +2 1 (highest) alo +4 +1 18 Ar 3 3 O 4 (lowest) -1 4 (lowest) O 1 (highest) 1 (highest) -2 2 +1 +1 3 4 (lowest) +1 4 (lowest) Explanation Check © 2021 McGraw Hill LLC. AlI Rights Reserved. Terms of Use Privacy Center | Accessibility

Decide how the sketches below would be listed, if they were listed in order of decreasing potential energy. That is, select "1" beside the sketch that shows the system with the highest potential energy, select "2" beside the sketch that shows the system with the next highest potential energy, and so on. Note for advanced students: since the units of each charge are not written, you may assume any convenient and reasonable unit, for example coulombs or multiples of e. 國 1 (highest) 1 (highest) ol. 2 2 +1 -1 +1 +3 Ar 3 3 4 (lowest) 4 (lowest) 1 (highest) +3 1 (highest) 2 2 +2 -2 3 4 (lowest) +1 4 (lowest) ? Explanation Check © 2021 McGraw Hill LLC. All Rights Reserved. Terms of Use | Privacy Center | Accessibility O O O O O O

The net change in the multistep biochemical process of photosynthesis is that CO₂ and H₂O form glucose (C₆H₁₂O₆)and O₂. Chlorophyll absorbs light in the 600 to 700 nm region.(a) Write a balanced thermochemical equation for formation of1.00 mol of glucose. (b) What is the minimum number of pho-tons with λ=680. nm needed to prepare 1.00 mol of glucose?

What unit measures the energy related to the work done by an electron through an electrical potential? O watt O electron volt O coulomb O joule