Physical Chemistry Answers

 Calculate the pH of an aqueous solution of 0.01 M sodium acetate. State any assumption made in your calculations. (K_a of acetic acid is 1.75 x 10^-5 mol L^-1 at 25 ˚C in water.)

Calcium carbide, CaC₂, is manufactured by reducing lime with carbon at high temperature. (The carbide is used in turn to make acetylene, an industrially important organic chemical.)

CaO(s)+3C(s)→CaC

2

(s)+CO(g)

CaO(s)+3C(s)→CaC2(s)+CO(g)   ΔH=464.8kJ

ΔH=464.8kJ 

Calculate the quantity of energy, in kJ, transferred when 0.432 mol carbon reacts with CaO(s). 

1. Calculate q, w, ∆U and ∆H if 1.65 mol of an ideal gas with Cv = R 3/2 undergoes a reversible adiabatic expansion from an initial volume Vi = 7.75 m3 to a final volume Vf = 20.5 m3 . The initial temperature is 300 K.

2. 2.25 moles of an ideal gas at 35.6oC expands isothermally from an initial volume of 26.0 dm3 to a final volume of 70.0 dm3 . Calculate w for this process (a) for expansion against a constant external pressure of 1.00 x 105 Pa and (b) for a reversible expansion. 

Bob runs into science one day it is hot so he takes off his shoes and leaves his goodies the instructions say to pour 10ML of chemical A into a beaker and then add 5G of chemical b to it. Bob pours 10ML of chemical A into the beaker. He realizes that it smells funny, so he sticks his nose in the beaker and takes a deep whiff he then dumps some of chemical B into the container the beaker overflows the bell rings and bob leave the lab. What are 3 things that bob should have done differently?

Silver crystalizes in an FCC structure. The edge length of its unit cell is 409 pm.

(a) What is the atomic radius of Ag in this Structure ?

(b) Calculate the density of Ag

A photon of 498 mm was emitted from a silicon atom. Calculate the energy of the atomic level and show that the atomic level are quantized