When an oxygen molecule binds to hemoglobin, substantial evidence shows that the iron(II) changes from a low spin d6 state to a high spin state. How might this affect the size of the iron cation and its ability to fit in the square planar site in heme? Evidence shows that this size change is what initiates the cooperative interaction among the four heme sites in the protein.

A solution is 5 mM in each of the following ions:

Indicate which of the metal ions would precipitate (or start to precipitate) at each of the following pH values. Indicate your answer with the number of the ion. Use 0 to indicate no precipitate. If more than one precipitate is expected, list the numbers in increasing order and separate them with commas. For example, 3,4,5 is ok but 5,4,3 is not.

pH = 5.00:

pH = 10.00:

What is the pH to the nearest 0.1 pH unit at which Zn(OH)₂ begins to precipitate?

pH =

Write the balanced reaction equation for the precipitation of calcium carbonate from
potassium carbonate and calcium chloride. Don't forget to show the states of matter.

For the reaction CuS(s) + H2(g) H2S(g) + Cu(s) ΔG°f (CuS) = −53.6 kJ/mol ΔG°f (H2S) = −33.6 kJ/mol ΔH°f (CuS) = −53.1 kJ/mol ΔH°f (H2S) = − 20.6 kJ/mol a. Calculate ΔG° and ΔH° at 298 K and 1 atm pressure. b. Will this reaction proceed spontaneously at 298 K and 1 atm pressure? c. Calculate the equilibrium constant for this reaction at 298 K. d. Calculate ΔS° at 298 K and 1 atm pressure. e. Calculate ΔG at 798 K and 1 atm pressure (assume ΔS° and ΔH° do not change with temperature). f. Calculate the equilibrium constant at 798 K and 1 atm pressure.

What feature is shared by formulas of colored compounds used as pigments?

Consider the solution formed from dissolving 11.20 ml of methylene chloride, CH2Cl2 (Mm=85.0g/mol, Density=1.33g/ml; non-electrolyte) into 102.8 ml of carbon tetrachloride, CCl4 (Mm=154g/mol, density=1.59g/ml; non-electrolyte). Determine the molality and molarity of the resulting solution assuming additive volumes.

I have no idea how to approach this problem:

Calculate the concentration of all species in a 0.145 M solution of H2CO3.

[H2CO3],

[HCO−3],

[CO2−3],

[H3O+],

[OH−]

Express your answer using two significant figures.

If a pure R isomer has a specific rotation of –146.0°, and a sample contains 80.0% of the R isomer and 20.0% of its enantiomer, what is the observed specific rotation of the mixture?

For my chemistry class we did a lab on "pKa determination of methyl red indicator", and for my lab report one of the questions asks to calculate the uncertainty (after calculating the average pka, etc.). Normally I would repeat the measurement 6 times to calculate the uncertainty, but due to limited starting materials I only did one complete measurement.

I am really confused on how to go about calculating the propagation of error for uncertainty for my calculations in this lab. (below are my results )

Table 3: Absorbance Values of the indicator solution in buffer solutions at different pH values.

A^u_{HMR, λMR} = 0.956

A^u_{HMR, λHMR}= 2.4654=2.47

A^u_{MR, λHMR} =1.8577= 1.86

A^u_{MR, λMR}= 2.3181= 2.32

Table 4: Computation of the pK_a values of methyl red indicator using Handerson-Hesselbalch equation.

How will the equivalence point volume change if you titrate the two solutions (solution 1: a 10mL vinegar solution that has a concentration of 5%(w/v%))(solution 2: a 10-mL vinegar solution that has a concentration of 5% (w/v%) together with 30mL of water). What is the pH of the equivalence point of the two solutions if you titrate with 0.3M NaOH?

How does a neutralization reaction differ from buffer?

Choose the best instrument for the situation and list a reason why (NMR, GCMS, LCMS, or IR)

1. Cattle farmers suspect that a nearby water source is contaminated with pesticide run-off from an adjacent farm and is causing health issues in their cattle.

2. An ink sample, collected at a crime scene, contains a unique set of organic dyes and chemicals that could identify the brand and type of pen used.

A city has 450,000 people. Suppose each person produces around 2 kg of waste daily that goes into landfills. (a) How much methane, in moles, would be produced if all of this waste was cellulose (-CH₂O-) based and could react anaerobically into methane? (b) How many homes could be heated from this is each person used 10⁸ kJ of energy per year if this methane was saved and combusted (heat of combustion for methane is -890 kJ/mol).