Other Chemistry Answers

A buffer iscreated by dissolving 0.450mol of sodium ascorbate(NaC6H7O6)and 0.500mol of ascorbic acid(HC6H7O6)in enough water to create 1.00Lof solution.. a) what is the original pH of the buffer

Benzene, C6H6 is a potent carcinogen. How many grams are in 0.250 mole sample of benzene

1. Between Be(OH)2 and Ra(OH)2, which is expected to be the more soluble and why?
2. Which is likely to be more soluble in water, SrSeO4 or CaSeO4, and why is it so?

1. Calculate the lattice enthalpy of KCl, in the rocksalt (B1) and Caesium chloride (B2) structures. Madelung constants: 1.748 (B1), 1.763 (B2). Electron charge 1.602 x 10^-19 C. r(KCl, B1) = 319 pm, r(KCl, B2) 332 pm. Which is expected to be the ground state structure at room conditions ?
2 。ZnSe exists in two polymorphs, Zink Blende (ZB) and Wurtzite (W). Assuming that r(ZnSe) does not sensibly change, which can be predicted to be the stable one at room conditions? Madelung constant ZB: 1.638, W: 1.641.

a) Define the terms symmetry element and point group.
b) Assuming that the solubility in water is high for NaNO3 and low for Cu(lO3)2.
i) derive expressions for the corresponding solubility products,
ii) draw a Hess’s law cycle for the dissolution of NaNO3 .

Using an appropriate diagram, illustrate the hydration of a Na+ ion.

d) With the aid of an appropriate figure, describe the meaning of the term
interstitial alloy.

zinc electrolyte solution has a composition of 65.4 g/L zinc(II), 24.3 g/L magnesium(II), and
98 g/L sulfuric acid. (Zn = 65.4, Mg = 24.3, H = 1, S = 32)
(a) Use the solubility diagram of hydroxides at 25 oC to estimate the percentage of zinc
that can be selectively precipitated as hydroxide by adjusting the pH value of the
solution to 7.
(b) The flow rate of the electrolyte having the above composition in the circuit is 0.8 m3
/h.
Estimate the rate of addition of lime ((Ca(OH)2, t/h) to precipitate zinc ions at pH 7
(Hint: Consider the neutralisation of H2SO4 as well as the precipitation of Zn(OH)2 and
write balanced chemical equations before commencing the calculation).
(c) Predict with reasons what would happen if the precipitation was carried out at pH 8.

What is the pH of 0.1 mol/DM of ethanoic acid which has a Ka of 1.74 * 10^-6

Write a procedure that you would follow to demonstrate the effect of increasingly higher concentrations of hydrochloric acid on its rate of reaction with antacid tablets.

Using Slater’s rules calculate the effective nuclear charge (Z*) for an outer valence electron in the following. Show clearly how you calculated your answer。
1. Carbon
2. Chlorine

Consider the following reaction at equilibrium:

C(s) + H2O (g) <--> CO (g) + H2 (g)

Which of the following conditions will increase the partial pressure of CO?
A) decreasing the partial pressure of H2O (g)
B) removing H2O (g) from the system
C) decreasing the volume of the reaction vessel
D) decreasing the pressure in the reaction vessel
E) increasing the amount of carbon in the system