Lactose/Glucose/Galactose Hydrolysis Diagnostic Tests
Hello!
I'm going to perform an experiment in which I will be adding powdered milk and various lactase medications into water, with the intention of having the lactose hydrolyze and produce glucose and galactose (Water + Lactose + Lactase enzyme :rarrow: Galactose + Glucose) to determine the most effective lactose-intolerance medication. To prove the production of the products of this reaction, I was intending on trying a blood-glucose meter, however this was unavailable due to prices. The other option I was considering was glucose test strips, but I'm unsure if I will have access to those. I have benedict's reagent available in the lab, but am unsure if this will work. Some sources have told me that only monosaccharides are detected by this indicator, and some have told me that it will also detect some disaccharides such as lactose, which would make benedict's reagent useless in this case. Can anyone confirm this?
I was also wondering if it would be possible to boil the water from the solution, leaving the solid glucose, galactose, and remaining lactose behind and using the increase in mass as quantitative evidence, similarly to when people purify salt water by boiling it (the mass of the powdered milk solid should increase slightly due to the addition of hydrogen and oxygen atoms in the hydrolysis reaction), but I am unsure if this is possible. I don't have much understanding of distillation processes.
Does anyone know any other possible tests that could be performed on the solution to prove the production of glucose or galactose, or the reduced amount of lactose present?
Just as reference, I am a high school student currently enrolled in Chemistry 30 IB SL.
Any suggestions are appreciated, thanks!
What would Flerovium (Element 114) look most similar to?
Got this question on my Grade 11 Chem Test (Chemical Bonding, Matter, etc)
It was a multiple choice. These are the answers I remember:
Red yellowish gas
Black powdery solid
Clear crystal
Grey metal
One or two other answers but I forgot (Don't have the test back yet). I assume it was just testing our knowledge on similar properties. The properties in the answers are in reference to other chemicals (Ex. Black powdery solid - Lead).
What would the answer most likely be?
Unexpected sublimation- iodine gas formation
Hi everyone! For a school project, I am conducting an experiment investigating the relationship between rate constant and temperature . The reaction I'm using is the iodine clock reaction, hydrogen peroxide variation.
The problem is that seconds after the starch and iodine complex and create a dark solution, a dark pink gas forms. I presumed this is iodine gas so I am now conducting the experiment in a ventilated area of the lab to avoid any irritations but I don't understand why the gas even forms in the first place, especially because the gas forms already at room temperature and its boiling point is about 183°C. Could it be that the concentrations of my reactants are too high? I only calculated them to be in the required ratio so that the thiosulphate is limiting, but I had not considered that perhaps they are too high.. although most solutions are either 0.01 or 0.02 M. Any help as to why the gas is forming is greatly appreciated!
Equimolar Gas Mixture Question
I was doing this question and I was wondering if my process and conclusion were valid...
Consider an equimolar mixture (equal number of moles) of two diatomic gasses (A2 and B2) in a container fitted with a piston. The gasses react to form one product (which is also a gas) with the formula AxBy. The density of the sample after the reaction is complete (and the temperature returns to its original state) is 1.50 times greater than the density of the reactant mixture.
a) Specify the formula of the product, and explain if more than one answer is possible based on the given data.
b) Can you determine the molecular formula of the product with the information given or only the empirical formula?
This was my process for (a):
1/2xA2 (g) + 1/2yB2 (g) :rarrow: AxBy (g)
Let z = initial moles of A2
Let z = initial moles of B2
Let a = used moles of A2
Let b = used moles of B2
Let c = produced moles of AxBy
Let ni = initial number of moles
Let nf = final number of moles
Let ?i = initial density of mixture
Let ?f = final density of mixture
Let m = mass of mixture
Let T = temperature
Let P = pressure
Let Vi = initial volume of container
Let Vf = final volume of container
?f = m/Vf
?i = m/Vi
?f = 1.5?i = 1.5m/Vi
1.5m/Vi = m/Vf
1.5Vf = Vi
ni = z + z = 2z
nf = c + 2z - a - b
a mol A2 × 1 mol AxBy/0.5x mol A2 = c mol AxBy
a/x = 1/2c
b mol B2 × 1 mol AxBy/0.5y mol B2 = c mol AxBy
b/y = 1/2c
a/x = b/y
PVi = niRT
1.5PVf = 2z × 8.31 × T
PVf/T = 11.08z
PVf = nfRT
PVf = (c + 2z - a - b) × 8.31 × T
PVf/T = 8.31(c + 2z - a - b)
11.08z = 8.31(c + 2z - a - b)
4/3z = c + 2z - a - b
-2/3z = c - a - b
Now, let B2 be the limiting reagent in the following reaction, that is b = z, and y > x...
Let z = 1 mole, and x = 1...
Find x:y...
-2/3z = c - a - b
-2/3z = c - a - z
-1/3z = c - a
1/3 = c - a
1/3 = 2a/1 - a
1/3 = a
a/x = b/y
1/3 = 1/y
y = 3
Therefore, the ratio of x:y is 1:3 respectively. Likewise, if one were to assume that A2 was the limiting reagent, then the ratio of x:y would be found to be 3:1 respectively.
As such, AxBy can be either AB3, or A3B.
(b) Not enough information is given in order to determine the molecular formula of the compound. As such, only the empirical formula can be calculated.
If anyone could let me know if this looks like the correct working and logic, that would be greatly appreciated!
Thank you,
How to predict products for equations of form AB + CB ->?
Title. Can't find anything on it online (probably because I'm not searching for the right term)
The specific equation I found this on:
N3O3 + H2O
My leading guess was synthesis but then I confused myself trying to follow that path.
Units of K, equilibrium constant.
I've found the value for K using Gibbs free-energy values (in KJ/mol) where Gibbs free-energy = -5.707*log(K).
Would that mean the units of K are KJ/mol as well?
Theoretical Yield Ni + 2HCl yields NiCl2 + H2
Hey everybody,
I have the balanced equation of Ni (s) + 2 HCl (aq) -> NiCl2 (aq) + H2 (g)
A.) If 12.0 moles of HCl were reacted, how many moles of Ni would be needed such that there was no excess?
B.) What is the theoretical yield (in grams) of NiCl2 from reacting 12.0 mol HCl?
C.) If 12.0 mol of HCl was reacted and the percent yield of the reaction was 78.5%, what was the actual yield (grams) of NiCl2?
A) Just use the coefficients of the balanced equation to relate moles of one thing to moles of another:
12 mol HCl X (1 mol Ni / 2 mol HCl) = 6 mol Ni
B) Again, use the coefficients from the equation to calculate moles NiCl2 formed. Then use the molar mass of NiCl2 to convert moles to grams:
12 mol HCl X (1 mol NiCl2 / 2 mol HCl) = 6 mol NiCl2
6 mol NiCl2 X (129.6 g/mol) = 778 grams NiCl2 (THIS is the theoretical yield for this reaction)
C) The percent yield is calculated as:
% yield = (actual yield / theoretical yield) X 100.
So, substituting what you know into this gives:
78.5% = (actual yield / 778 g) X 100
0.785 = actual yield / 778
actual yield = 611 grams NiCl2
Do these answers make sense?
Why nitric and not sulfuric acid for gold recovery?
When extracting gold from gold fingers (PCI plated connectors of a PCI card) everybody uses Nitric acid. Why not to use Sulfiric acid? Sulfuric acid is cheaper and it is more stronger. Can someone explain it to me?
Equilibrium Volume Question
I noticed that this question has been posted on this forum previously, however, I couldn't see that an actual numerical answer was given. I was just wondering if the following process seemed right, and, as such, if the solution is correct (I have no way of checking). I haven't covered this concept yet in my Chemistry class, but I thought that I'd give it a go anyway:
"Consider the reaction A(g) + D(g) ::equil:: C(g) for which K = 130. Assume that 0.406 mol C(g) is placed in a container fitted with a piston. The temperature is 300.0 K, and the barometric pressure on the piston (which is assumed to be massless and frictionless) is constant at 1.00 atm. The original volume (before the 0.406 mol C(g) begins to decompose) is 10.00 L. What is the volume in the cylinder at equilibrium?
My working was as such:
Vi = 10.00 L
P = 101.325 kPa
T = 300.0 K
ni = 0.406 mol C(g)
CC(g) = 0.406/10 = 0.0406 mol/L
K = [C]/[A][D]
130 = 0.0406/x2
x = 0.0177 mol/L
x = y/Vf
0.0177 = x/Vf
nf = 0.406 - y + y + y = 0.406 + y
PVf = nfRT
101.325Vf = (0.406 + y) × 8.31 × 300.0
Vf = 24.604y + 9.989
0.0177 = y/(24.604y + 9.989)
0.177 = 0.565y
.. y = 0.312 mol
0.0177 = y/Vf
Vf = y/0.0177 = 0.312/0.0177 = 17.674 L
If anyone could let me know if this process is right, that would be greatly appreciated. I'm not certain if the volume is allowed to change in the equilibrium expression (as I have assumed).
Thanks,
Changing from cam followers
Hi folks
been a while since i've been here and also able to play with something new. We have a small machine that operates with a small motor driving a shaft at 4 RPM. There are a few single lobe cams on the shaft and there are ball bearing followers they are acting on. The part the followers are on, i'll call lifters, are solid an act on a spring that acts on a part being squeezed or clamped. The force is very low and buffered by the springs. I'd like the eliminate the bearings and maybe have the cam lobes directly act on the lifters but have their path sort of off centre so the lifter part turns when the cam wipes across the face lessening the friction. this is a NON lubricated application so all the parts are dry. The units already produced are already lasting 20 or 30 years and the bearings are replaced as wear items at least twice in that time. Any other broken or worn parts in this system are an anomaly.
I'd like to try and predict what the results will be from this change and ways to mitigate what could be excessive wear. like hard chrome or Teflon coatings for example?