The pyruvate dehydrogenase complex catalyzes the following reaction:

pyruvate + coa + nad+ → acetyl-coa + co2 + nadh

we will discuss this enzyme in detail on class, but for now all you need to know is the overall reaction that it catalyzes.

in a spectrophotometer, nadh absorbs light at 340 nm, nad+ does not.

the beer-lambert law relates the absorbance of a solution to its concentration, and states that:

a = ε.c. l

where a is absorbance, ε is the molar extinction coefficient, c is concentration, and l is the path length of the solution in the spectrophotometer. in all the calculations that follow assume l = 1 (ie all measurements were made in a cuvette with a 1 cm path length), so l can effectively be disregarded (although not its unit).

the molar extinction coefficient for nadh is 6,300 litres/mol cm-1 [or (mol/litre)-1 cm-1 or m-1 cm-1]. the molar extinction coefficient is the absorbance of a 1 molar solution in a 1 cm path length cuvette.

Iam not sure butch i thinnk it is ab

Idon't see the pic?

What essay do you want us to write?

Note that 2 mol dm⁻³ = 2 mol/(dm³)outline: we're given the concentration of hcl, which is  2 mol dm⁻³ (cubic meters in the denominator can represent volume, so i know this is concentration). we're an amount of calcium carbonate caco₃, which is 5 g. we're presented with a chemical equation which includes caco₃ and hcl. we are told to find the volume of hcl. from what we see so far, this seems to be a stoichiometry  problem. we'll have to use the given information about calcium carbonate to find the amount of moles of hcl needed to fully react with calcium carbonate. then we'll have information about the moles of hcl and the concentration of hcl; that will be enough to figure out volume according to the formula concentration = moles / volume.======all the answer choices are not in dm.convert the given concentration so that it uses cm⁻³.we can use conversion factors. we have to cube our conversion factors so that dimensional analysis works.we can convert to meters first, using the fact that     10 dm = 1 m  ⇔ 10³ dm³ = 1 m³then we use the fact that     10² cm = 1 m ⇔ (10² cm)³ = (1 m)³ ⇔ 10⁶ cm³ = 1 m³so converting:     now we have to find the moles of hydrochloric  acid neededfind the moles of calcium carbonate. we have to find the molar mass of calcium carbonate, caco₃, which can be found by    molar mass = (mass ca) + (mass c) + 3(mass o)    = 40 + 12 + 3(16)    = 100 g/molconvert the given 5 g to moles:     mol caco₃ = 5 g caco₃ * 1 mol/(100 g) = 0.05 mol caco₃use stoichiometry (ratios) to figure out the moles of hcl needed. ratio wise, there's 2 hcls for every caco₃, so use dimensional analysis    mol hcl = mol caco₃ * (2 mol hcl) / (1 mol caco₃)    = 0.05 mol hcl * 2    = 0.1 mol hcl  we have 0.1 mol hcl and concentration of hcl (0.002 mol/cm³).we need to find volumesince concentration = moles / volume, rearrange to get     volume = moles / concentration    volume = 0.1 mol / (0.002 mol/cm³)    volume = 50 cm³