1. Explain how Cl⁻ can be determined by cathodic stripping voltammetry at a silver-working electrode.

6.

Open the PhET States of Matter Simulation to answer the following questions:

(a) Select the Solid, Liquid, Gas tab. Explore by selecting different substances, heating and cooling the systems, and changing the state. What similarities do you notice between the four substances for each phase (solid, liquid, gas)? What differences do you notice?

(b) For each substance, select each of the states and record the given temperatures. How do the given temperatures for each state correlate with the strengths of their intermolecular attractions? Explain.

(c) Select the Interaction Potential tab, and use the default neon atoms. Move the Ne atom on the right and observe how the potential energy changes. Select the Total Force button, and move the Ne atom as before. When is the total force on each atom attractive and large enough to matter? Then select the Component Forces button, and move the Ne atom. When do the attractive (van der Waals) and repulsive (electron overlap) forces balance? How does this relate to the potential energy versus the distance between atoms graph? Explain.

A beaker with 115 mL of an acetic acid buffer with a pH of 5.000 is sitting on a bench top. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 4.80 mL of a 0.420 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740. Express your answer numerically to two decimal places. Use a minus ( − ) sign if the pH has decreased.

Indicate whether or not each of the following ionic compounds will undergo hydrolysis and predict whether the resulting solution pH will be acidic, basic, or indeterminate (both ions undergo hydrolysis).

(a) NH4ClO4

acidic hydrolysis

basic hydrolysis

indeterminate hydrolysis

no hydrolysis

(b) LiBr

acidic hydrolysis

basic hydrolysis

indeterminate hydrolysis

no hydrolysis

(c) PbSO4

acidic hydrolysis

basic hydrolysis

indeterminate hydrolysis

no hydrolysis

(d) Co(ClO3)2

acidic hydrolysis

basic hydrolysis

indeterminate hydrolysis

no hydrolysis

You may have heard that ice skaters actually skate on a thin layer of water rather than solid ice (which reduces friction on the blade and allows them to skate faster). Let’s work through a calculation to determine if this statement is reasonable. Estimate the pressure exerted by a 200-lb hockey player, standing on two blades that are 0.1 mm  20 cm. Calculate the melting point of ice below the player, assuming that the density of ice under these conditions is approximately 0.915 g cm^–3 and that of liquid water is 0.998 g cm^–3. Assuming a typical temperature of ice in a skating rink is 27 °F, does a hockey player skate on ice or water?

Chelating agents are important for many biological processes. List and describe three such processes.

For each of the following five reactions, circle the specific chemical species that is: reduced, and draw a box around the specific chemical species that is oxidized:

a) MnO₂ (s) + 2 I^- (aq) +4 H⁺ (aq) --> Mn²⁺ (aq) + I₂ (aq) + 2 H₂O (l)
b) Cd (s) + 2 NiO(OH) (s) + 2 H₂O (l) --> 2 Ni(OH)₂ (s) + Cd(OH)₂ (s)
c) NH₄⁺ (aq) + 2 O₂ (g) --> NO₃^- (aq) + 2 H⁺ (aq) + H₂O (l)
d) 2 CuFeS₂ (s) + 4 O₂ (g) --> Cu₂S (s) + 2 FeO (s) + 3 SO₂ (g)
e) 2 K₂FeO₄ (aq) + 3 Zn (s) --> Fe₂O₃ (s) + ZnO (s) + 2 K₂ZnO₂ (aq)

A) What is the rate constant for the reaction with an average time of 48.6 seconds, between 3.00 ml of 0.1 M t-butyl chloride, 3 ml 0.01 M NaOH, 4 ml water with 3 drops bromophenyl blue solution.

B) What is the rate constant for the reaction with an average time of 48.6 seconds, between 3.00 ml of 0.1 M t-butyl chloride, 6 ml 0.01 M NaOH, 1 ml water with 3 drops bromophenyl blue solution.

Name the kinds of attractive forces that must be overcome in order to perform the following tasks. Select all that apply.

1) Dissolve CsI in liquid HF:

Dipole-dipole interactions

Ionic Bonding

Ion-dipole interactions

Dispersion Forces

Hydrogen Bonding

2) Melt potassium metal:

Dipole-dipole interactions

Ionic Bonding

Ion-dipole interactions

Dispersion Forces

Hydrogen Bonding

A generic solid, X, has a molar mass of 80.4 g/mol. In a constant-pressure calorimeter, 16.0 g of X is dissolved in 337 g of water at 23.00 °C.

The temperature of the resulting solution rises to 28.70 °C. Assume the solution has the same specific heat as water, 4.184 J/(g·°C), and that there\'s negligible heat loss to the surroundings. How much heat was absorbed by the solution?

how much heat was absoped

waht is the enthrapy

a. explain in structure and words the observation that soap does not work properly in very low PH water or hard water which has calcium and magnesium ions.

b. would a soap made form N,N,N-trimethyl octadecyl ammonium chloride have thesame problems as a long chain of carboxylic acid? Explain

Consider the titration of a 28.0-mL sample of 0.180 M CH3NH2 with 0.145 M HBr. (The value of Kb for CH3NH2 is 4.4×10−4.)

Determine the pH after adding 6.0 mL of acid beyond the equivalence point.

Express your answer using two decimal places.

Describe the preparation of 3.00 L of 0.150 M glycine buffer, pH 8.1, from glycine and 1.00 M NaOH. What mass of glycine is required? The appropriate pKapKa of glycine is 9.6. Apply appropriate significant figures.