Describe how you would make a 500 ml solution of 20% methylene blue from a 90% s
ID: 989205 • Letter: D
Question
Describe how you would make a 500 ml solution of 20% methylene blue from a 90% stock solution. How much methylene blue stock and water do you need to make this solution (in ml) Describe how you would make a 1 L of solution of 5% methylene blue from a 75% stock solution. How much methylene blue stock and water do you need to make this solution (in ml) If you measured out water and it weighed 68 mg, how much is that in ml What would the scale read in grams What are two reasons a scientist might use a spectrophotometer Suppose you were using a spectrophotometer and it was "kind of broken". The instrument was unable to switch to Abs and all the data you collected was % T. Convert the following data from % T to Abs: 54, 33, and 12. why is it important to blank a spectrophotometer before each use If you were going to measure samples of bacteria present in a nutrient broth solution, what would you use to blank the spectrophotometer What is an absomtion maximum Why did we need to calculate it in this labExplanation / Answer
1. 500 x 20 /90 = 111.11 ml is need
2. 1000 x 5/ 75 = 66.66ml is need
3. 68 microliter
4. to check absorbance and from the absorbance they are getting information what they need
5. If we substractthe transmittance from 100 we will get absorbance . Hence absorbances are 46, 67 and 88
6.Blank might have some absorbance. hence if we run a blank and substract from sample absorbance we will get Acccurate absorbance of sample.
7. a compound will absorb a maximum light at particular wavelengt which is called absorbance maximum