Determine the pH at the equivalence (stoichiometric) point in the titration of 22 mL of 0.22 M H₃BO₃(aq) with 0.21 M NaOH(aq). The K_a of H₃BO₃ is 5.8 x 10^-10

^{Answer is 11.13}

Ammonia is produced directly from nitrogen and hydrogen by using the Haber process. The chemical reaction is
N2(g)+3H2(g)?2NH3(g) Answer is in kJ / 2moles NH3

Part A.Use bond enthalpies to estimate the enthalpy change for the reaction. Express your answer using two significant figures.

Part C. Calculate the true enthalpy change as obtained using ?H?f values.

Express your answer using two significant figures.

Part D. Compare the enthalpy change you calculate in (a) to the true enthalpy change as obtained using ?H?f values. (essay question)

A 20.0mL sample of a 2.00M potassium sulfate solution is mixed with 14.8mL of a 0.880M barium nitrate solution and this precipitation reaction occurs:

K2SO4(aq)+Ba(NO3)2(aq)?BaSO4(s)+2KNO3(aq)

What is the theoretical yield?

Draw the major alkene product formed from dehydrating the following alcohols?

a) 2-methylcyclohexanol

b) 2,3-dimethylcyclohexanol

c) 1,2,2-trimethylcyclohexanol

d) 2,2-dimethylcyclohexanol (hint: consider carbocation shifts)    

e) 1,2-cyclohexanediol (hint: consider keto-enol tautomerism)

The data set below was collected from a differential, isothermal PFR analyzing the conversion of A +B

Consider the cell described below at 291 K:

Sn | Sn²⁺ (0.753 M) || Pb²⁺ (0.921 M) | Pb

Given E^o_Pb²⁺→Pb = -0.131 V, E^o_Sn²⁺→Sn = -0.143 V. Calculate the cell potential after the reaction has operated long enough for the Sn²⁺ to have changed by 0.325 mol/L.

For BIOCHEM

1. When we refer to "anabolic" biochemical reactions, what do we mean? Give an example of an anabolic reaction. (You can describe in words, you dont need to show a balanced reaction).

2. Stage 1 of metabolism refers to the beginning of deigestion of carbohydrates, fats and proteins. Where do proteins begin stage 1 digestion? What happens at the beginning of Stage 1 digestion of proteins?

3. Which coenzymes serves as an oxidizing agent in glycolysis?

4. Write the net reaction for glycolysis.

why is proline more hydrophilic than all of the other hydrophobic amino acids? ( need to consider the electronegativity of nitrogen and carbon and then carefully look at proline's structure in relation to other hydrophobic amino acids

Which of the following compounds are insoluble in water?

aluminum hydroxide

lithium chloride

sodium phosphate

lead(II) bromide

A student mixes 31.0 mL of 3.24 M Pb(NO3)2(aq) with 20.0 mL of 0.00217 M NaI(aq). How many moles of PbI2(s) precipitate from the resulting solution? What are the values of [Pb2 ], [I–], [NO3–], and [Na ] after the solution has reached equilibrium at 25 °C?

what is heavy metal contamination

Construct a curve for the titration of 50.00 mL of a 0.1000 M solution of ethylenediamine with a 0.2000 M solution of HCl in the following table. For each titration, calculate the pH after the addition of 0.00, 12.50, 20.00, 24.00, 25.00, 26.00, 37.50, 45.00, 49.00, 50.00, 51.00, and 60.00 mL of HCl.

A mixture of 8-hydroxyquinoline complexes of aluminum and magnesium weigh 1.0843 g. When ignited in a furnace open to the air, the mixutre decomposed, leaving a residue of Al2O3 and Mg weighing 0.1344. What is the weight percent of Al(C9H6NO3) in the original mixture? AlQ3 + MgQ2 ? Al2O3 + MgO

How many of the following responses are true?

1. 3-bromo-3-methylpentane will undergo substitution through an S_N2 mechanism
2. If R-2-bromopentane is allowed to react with OH^- the product will be S-2-pentanol
3. S_N1 leads to a racemization of sterechemistry due to the nucleophile attacking from the backside and the leaving group leaving
4. S_N2 leads to a racemization of sterechemistry due to the nucleophile attacking from the backside and the leaving group leaving
5. A primary alkyl halide will tend to react through an S_N2 mechanism because there is little hindrance to backside attack and a primary carbocation is not very stable

ITEM 17 The decomposition of NH4HS is endothermic:
NH4HS(s)?NH3(g)+H2S(g)

Which change to an equilibrium mixture of this reaction results in the formation of more H2S?

Which change to an equilibrium mixture of this reaction results in the formation of more ?