What is the isoelectric point, pl, for the pentapeptide, MGHFD 4.8 3.1 Show work O 7.8 2.3 O 9.5

A chloride ion and a sodium ion are separated by a center–center distance of 0.5 nm. Calculate the interaction energy (the energy required to pull them infinitely far apart) if the medium between them is (a) water and (b) n-pentane . Express the energy in joules per mole of ion pairs. [Note: The charge on an electron is 1.602 * 10-19 C, Avogadro’s number is 6.02 * 1023 molecules/mol.]

Explain the formula:   Ccal ΔTcal + mCpΔTwater + qrxn = 0

F. 150 135 120 E 105 90 75 B 60 45 30A 15 Heat (kJ) Created by E. Le for Virtual Virginia (2021) Using this heating curve, complete the following statements: 1) The substance's melting or freezing point can be found between points [ Select] and [Select] (Select the points alphabetically; for example, "X and Y" not "Y and X") 2) Between points ( Select) and [ Select] the substance is in the liquid phase. (Select the points alphabetically; for example, "X and Y" not "Y and X") 3) At 50°C, the substance is a ( Select] Temp. (°C)

4G VOLTE O 76 14 4:58 7 February 2021 4:57 PM (ii) Calculate the lattice energy of Silica oxide (SiO2) from the data given below: Si (g) - Si (s) AH° = -454 kJ mol-1 S1A+ (E) + 4e" Si (3) AH° = -9949 kJ mol-1 20 (g) – 02 (3) AH° = -498 kJ mol-1 02 (3) 0 (g) + 2e AH° = -737 kj mol-1 Si (s) + 02 (3) → SiO2 (s) s14+ (6) - 202- (3) – SiO2 (s) AHf (SIO2)= -910.9 kj mol1 AH°lattice = ? Share Favourite Edit Delete More

CTQ 7: Why is it incorrect to describe the process of boiling as 2H,0(1) → 2H,(g) + 0,(g)?

18. (a) Molecule N₂H4 (1) + 2 H₂O2 (1) → N2(g) + 4 H₂O (1) Complete the following table: Lewis Dot Structure (use dots or lines to show bonds) (b) (c) (d) N₂H4 H₂O2 N₂ H₂O Calculate the AH°rxn using average bond energies (Table 9.4 in textbook) Calculate the AH°rxn using the standard enthalpies of formation (Appendix 2 in textbook) Why are these two values slightly different?

How are C–Mg and C–Li bonds polarised?

For K*-Cl ion pair, the sum of the attractive and repulsive energies depends on the distance between ions according to the equation below (E in eV per ion pair and r in nm). 1.436, 5.86 x 10-6 E = r r6 (a) derive an expression for the bonding energy E and r at equilibrium. Then calculate the (b) bond energy in kJ/mol and (c) bond length in nm for KCI.

The breaking of the O-O bond in peroxydisulfuryl difluoride (FO,SOOSO,F) gives FO,SO: (FO2SO)2 2 2 FO2SO The compound on the left of this equation is a colorless liquid that boils at 67.1°C. Its vapor, when heated to about 100°C, turns brown as the product of the reaction forms. Suppose that, in a sample of the vapor, the intensity of the brown color doubles between 100°C and 110°C and that the total pressure increases only by the 2.7% predicted for an ideal gas. Estimate AH° for the preceding reaction.