1) Constant-volume calorimeters are sometimes calibrated by running a combustion reaction of known ΔE and measuring the change in temperature. For example, the combustion energy of glucose is 15.57 kJ/g. When a 2.500 g sample of glucose burns in a constant volume calorimeter, the calorimeter temperature increases from 21.45 to 23.34°C. Find the total heat capacity of the calorimeter (in kJ/K).

2)An electrical heater is used to add 18.25 kJ of heat to a constant-volume calorimeter. The temperature of the calorimeter increases by 3.40°C. When 2.25 g of ethanol (C₂H₅OH) is burned in the same calorimeter, the temperature increases by 12.45°C. Calculate the molar heat of combustion for ethanol (enter in kJ).

3)A 0.90 g sample of caffeine, C₈H₁₀N₄O₂, burns in a constant-volume calorimeter that has a heat capacity of 7.85 kJ/K. The temperature increases from 298.25 K to 303.34 K. What is the molar heat of combustion of caffeine (in kJ).

4)Use standard enthalpies of formation to determine ΔH^o_rxnfor:

2Al(s) + 3Cl₂(g) → 2AlCl₃(s)   Find the change in internal energy for this reaction. Enter in kJ.

5)Use standard enthalpies of formation to determine ΔH^o_rxn for:

2NH₃(g) + 3O₂(g) + 2CH₄(g) → 2HCN(g) + 6H₂O(g) Find the change in internal energy for this reaction. Enter in kJ.

Second eyes for a final draft please-

A small baggie of glucose solution is placed in a small beaker of distilled water. We pulled a sample of water (colorless) from the bottom of the beaker and add Benedict solution (light blue) to it which turned it to a light blue color. Adding Benedict solution to glucose tests for presence of reducing sugars that have the aldehyde functional group – CHO (or, free ketone group I.e. alpha-hydroxy ketone, too). When the Benedict solution was added, the glucose solution immediately takes the color of Benedict's reagent and turns it to light blue. When the mixture was heated in boiling distilled water, aldehyde group gets oxidized by accepting an O-atom from OH- and gives up and electron that copper ion (Cu2+) accepts and then become reduced which turns Benedict's solution and sugar into an orange color indicating a positive result due to the color change proving diffusion occurred. Test was not redone. Our group and the group we compared our results with had same results and color.  

a.) How many grams of NH3 can be produced from 4.19 mol of N2 and excess H2? Express your answer numerically in grams.

b.) How many grams of H2 are needed to produce 11.70g of NH3

c.) How many molecules (not moles) of NH3 are produced from 2.64x10^-4 g of H2

Suppose that you have 125 mL of a buffer that is 0.260 M in both hydrofluoric acid (HF) and its conjugate base (F-). Calculate the maximum volume of 0.400 M HCl that can be added to the buffer before its buffering capacity is lost. Please help!!

The equilibrium constant, K, for the following reaction is 10.5 at 350 K.

2CH₂Cl₂(g) =CH₄(g) + CCl₄(g)

An equilibrium mixture of the three gases in a 1.00 L flask at 350 K contains 5.12×10^-2 M CH₂Cl₂, 0.166 M CH₄ and 0.166 M CCl₄. What will be the concentrations of the three gases once equilibrium has been reestablished, if 0.121 mol of CH₄(g) is added to the flask?

Chemistry of lipid oxidation?

–State specific aspects (aromas, colors) that play into this

An aqueous solution contains 0.480 M acetic acid. How many mL of 0.327 M potassium hydroxide would have to be added to 250 mL of this solution in order to prepare a buffer with a pH of 4.680?

(please explain. thank you!)

Balance each of the following half-reactions, assuming that they occur in basic solution. CH3OH(aq)?CH2O(aq)

A certain first-order reaction has a rate constant of 3.00×10⁻² s−1s−1 at 21 ∘C∘C. What is the value of kk at 51 ∘C∘C if EaEaE_1 = 76.0 kJ/molkJ/mol ?

Express your answer using two significant figures.

Another first-order reaction also has a rate constant of 3.00×10⁻² s−1s−1 at 21 ∘C∘C. What is the value of kk at 51 ∘C∘C if EaEaE_2 = 110 kJ/molkJ/mol ?

Express your answer using two significant figures.

Which of the following are generally required in a E2 reaction? Choose all that apply.

A. strong base

B. anti-coplanar orientation of eliminated groups

C. Primary or secondary substrate

D. Good leaving group

E. strong nucleophile

What is the molarity of a 7.48 m solution of ethanol (C2H5OH) if the density of this solution is 0.869 g/ml?

A reaction has a rate constant of 1.22*10^-4/s at 27 ⁰C and 0.230/s at 78 ⁰C. Determine the activation barrier for the reaction. What is the value of the rate constant at 18 ⁰C?

From the Fe2+ concentrations given determine the mg of Fe in the original vitamin tablet. You will need to convert ug/mL into mg of iron. You also have to consider that the original vitamin tablet sample was diluted to 250mL in a volumetric flask and then 5mL of that sample was diluted to 100mL in a volumetric flask. Please show all equations used and work done.

1. Concentration of 0.141738

2. Concentration of 0.1307058

3. Concentration of 0.1354047