Posted: 23 January 2012 at 6:46pm | IP Logged
A device called pitot tube is used to measure the airspeed of a plane. A simplified model of the tube is a manometer with one side connceted to a tube facing directly in the wind. On that particular side of the tube( the static chamber), the air is motionless. The other side is connected to a tube into which the air moves at the speed of the plane. This air flows right past small holes, which are used to communicate the decrease in the pressure on the othe side of the manometer. If the manometer uses mercury and the levels differ by 25cm, what is the airplane speed in km/hr? The density of the air at the plane's altitude is taken to be 0.90kg/m^3. How does the speed you get compare to what is posted on the internet of commercial airliner's cruising speeds?
Plus i have a question regarding spectrophotometery lab:
Spectrophotometer was set at 405nm and 2ml of 50mM glycine buffer at pH8.6, 0.40ml of pNPP. Then 100muL of alkaline phosphatase was mixed. we know that [pNP]final = [pNPP]initial. Final absorbance was recorded as 1.025.FIND
- final [pNP] in the cuvette i found this one to be 0.05631. I dont know if its right. plus I am confused about units.
- initial [ pNPP] in the cuvette.This would also be 0.05631 i guess.
- [pNPP] in the (undiluted) unknown. For this one i am confused about undiluted part. the TA said that i have to take in account the indilluted part.
- Concentration of the pNPP in the unknown in the most appropriate unit. e.g. mg/ml, mug/mL,ng/mL. The molecular weight of pNPP is 371.14).
Q: A solution with a concentration of 4.23mg/ml(MW= 321.4g/mol) gives a transmittence value of 28.9% in a 1.5cm cuvette at 280nm. Calculate the molar absorptivity of the sample. Show your work.
Q: if the protein is pure and has a MM of 150kDA what is the molar concentration in appropriate units?
thanks in advance.