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Consider a spherical Gaussian surface of radius R centered at the origin. A charge Q is placed inside the sphere. To maximize the magnitude of the electric flux through the Gaussian surface, the charge should be located at

Which type of tissue lines the lumen of this vessel?  

The point charge at the bottom of the figure is Q = + `Q` nC, and the curve is a circular arc. What is the magnitude of the force on the charge Q due to the other point charges shown? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2 and 1 nC = 1 × 10-9 C) Hint: First draw the force vectors on Q due to the 3 charges (opposites attract, like repel). Then calculate the magnitude of the force between Q and each of the three charges. Then break them into x- and y- components and make sure you have the correct sign for each component (positive for components pointing to the right or up, and negative for components pointing to the left or down). For example F12x = |F12|cos(angle) and choose the correct sign for that component. Finally, add all the x’s together and all the y’s together. Those are the components of the total force on Q. Then find the magnitude of that vector.   Give your answer in units of N (1 N = 10-6 N) and round to the nearest whole number.

A compound with a molecular formula C8H15ClO3 has the 1H NMR spectrum given. The IR spectrum shows a strong absorption at 1800 cm-1. Which of the structures shown is consistent with this spectrum?

What is the pH of the solution which results from mixing 75 mL of 0.50 M NH3(aq) and 75 mL of 0.50 HCl(aq) at 25 °C? (Kb for NH3 = 1.8 x 10–5) a. 0.60 b. 2.67 c. 4.74 d. 4.93 e. 9.26

Choose the correct table for the polynomial function   .

4. Which is the best acid to use in the preparation of a buffer with pH = 9.3? A. CH3NH2 (Kb = 3.7 × 10–4) B. NH3 (Kb = 1.8 × 10–5) C. NH2OH (Kb = 9.1 × 10–9) D. C6H5NH2 (Kb = 4.3 × 10–10)

What is the pH of a 0.28 M solution of sodium propionate, NaC3H5O2, at 25°C? (propionic acid, HC3H5O2, is monoprotic and has a Ka = 1.3 x 10–5 at 25°C.) a. 6.26 b. 7.83 c. 8.10 d. 8.74 e. 9.17

In which reaction is ΔrS° expected to be negative? a. 2C2H6(g) + 7O2(g) -> 4CO2(g) + 6H2O(l) b. Ga(l) -> Ga(s) c. H2O(l) + 2SO2(g) -> H2SO4(l) d. CO2(g) -> CO2(s) e. all of above

The standard free energy change for a chemical reaction is +13.3 kJ/mol. What is the equilibrium constant for the reaction at 125 °C?  a. 2.8 x 10–6 b. 2.0 x 10–5 c. 4.7 x 10–3 d. 3.8 x 10–2 e. 1.8 x 10-2