When comparing two enzymes against a single substrate it is best to compare which of the following experimentally determined values?

kcat

Km

none of these

Vmax

k2

The sulfate ion level in a municipal water supply is given as 46.0ppm .

What is [SO2?4] in this water? in units M

1. A large quantity of chemical energy is stored in a gummy bear, which is primarily sugar, C12H22O11. When a gummy bear is placed in molten KClO3, the sugar is oxidized according to the following thermochemical equation: C12H22O11(s) + 8 KClO3(l) ⇒ 8 KCl(s) + 12 CO2(g) + 11 H2O(g) ∆Hrxn = −5488 kJ
If a gummy bear has an average mass of 0.5250 g and is 91.40% sugar, then how many whole gummy bears does it take to bring a cup of water (250.0 mL) at an initial temperature of 20.0°C to the boiling point? The boiling point of water is 100.0°C, the density of water (20°C) is 0.9982 g/mL, and the specific heat capacity of water is 4.184 J/(g•°C).

2. When 50.0 mL of 1.00 M Pb(NO3)2 (d = 1.30 g/mL) and 50.0 mL of 1.50 M KI (d = 1.18 g/mL) are mixed in a constant-pressure calorimeter, a precipitate forms and the temperature of the mixture increases from 19.0°C to 23.3°C.
(a) Indicate if the precipitation reaction is endothermic or exothermic.
(b) Write both the complete and net ionic chemical equations, including phase symbols, for the reaction that occurs when the two solutions are mixed.
complete:
net ionic:
(c) Calculate the moles of the limiting reactant.
(d) Calculate ∆Hrxn in kilojoules for the precipitation reaction, assuming that the heat capacity of the calorimeter is 15 J/°C in this case and the specific heat capacity of the solution after mixing is the same as that of water.

1) 65. mLs of water is added to 403 mLs of 2.39 M solution of HCl. What is the new molarity of the solution?

2) How much water must be added to 403mLs pf 2.39 M solution of HCl. What is the new molarity of the solution?

The rate consant for the reaction
I+I+Ar---->I₂+Ar
is 0.59 x 10¹⁶ cm⁶mol^-2s^-1 at 293K. What is the half-life of I is [I]_o= 2 x 10^-5 mol L^-1 and [Ar]= 5 x 10^-3 mol L^-1?

Select all of the following equations that would most likely give a positive value for ΔS. -- How do you determine the value of ΔS just by a reaction???

1. AgNO₃ (aq) + KCl (aq) → AgCl (s) + KNO₃ (aq)

2. 2 NOBr (g) → 2 NO (g) + Br₂ (g)

3. 2 Al (s) + 3 Cl₂ (g) → 2 AlCl₃ (s)

4. N₂ (g) + O₂ (g) → 2 NO (g)

5. 2 NO (g) + O₂ (g) → 2 NO₂ (g)

6. 2 NO₂ (g) → N₂O₄ (g)

7. 2 NH₃ (g) → N₂ (g) + 3 H₂ (g)

8. 2 CH₄ (g) → C₂H₄ (g) + 2 H₂ (g)

5.0 mL 1.0 M NaOAc + 28.0 mL 1.0 M HOAc

pH= 3.68

Calculations:

1. [H+] =?

2. [OAc-]=?

3. [HOAc]=?

4. Ka=?

Do the calculations for the titration of 50.00 mL of a 0.1000 M solution of H₂SO₃ with a 0.2000 M solution of NaOH. Calculate the pH after the addition of 0.00, 12.50, 25.00, 37.50, 50.00, and 60.00 mL of NaOH. Provide the answers in the blanks below. K_a1(H₂SO₃)=1.23×10^-2; K_a2(HSO₃^-)=6.60×10^-8.

Part A

Which of these weak acid solutions has the greatest percent ionization?

Which of these weak acid solutions has the greatest percent ionization?

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Part B

Which solution has the lowest (most acidic) pH?

Calculate the pH of a 0.368 M solution of ethylenediamine (H2NCH2CH2NH2). The pKa values for the acidic form of ethylenediamine ( H3NCH2CH2NH3 ) are 6.848 (pKa1) and 9.928 (pKa2). Calculate the concentration of each form of ethylenediamine in this solution at equilibrium.

How many acetyl CoA molecules are formed when 1 molecule of myristic acid (14:0) is broken down?

5. According to your experimental results, how much vitamin C would you get from a 4 oz. (120 mL) serving of fresh orange juice?

a. Less than the RDA.

b. More than the RDA.

c. Almost exactly the RDA.

Explain your answer:

Please show all work and derivations

A "barrel of oil" in international trade has a volume of 42 US gallons, or 159 L. How much heat would be released if 159 L of pure n-octane (C8H18) was burned completely at constant pressure, and with products and reactant at 298 K. The standard enthalpy of combustion of n-octane is -5471 kJ/mol and its density is 0.703 g/cm^3.

A compound has an M+ ion at 102 amu. There is no M+2 peak. The only IR absorbances in the interpretable region are at 3500 and 2900 cm−1. The 13C NMR spectrum shows three resonances at δ 70 (d), 35 (t), and 30 (t). Draw a structure consistent with this information.