# chem

posted by .

If I added 60 drops of water to a beaker and weighed it, and then added another 60 drops of water to the breaker;
How would I calculate number of drops per gram.
How do I use density to calculate the number of drops per mL?

• chem -

record the beaker with the sixty drops weight. Then weigh after the second sixty drops is added.

density=volume/mass= sixty drops/changeinmass

that will give you the density in drops/gram

if you want grams per drop, then do the reciprocal.

changeinmass/60.

Now, for drops per ml. You know the density of water, 1g/ml. So the change in weight you recorded for the second sixty drops is = change in ml.

60/changeinml (same as change in grams).

• chem -

#drops x (grams/drop) = grams.
You know # drops. You know grams. Calculate grams/drop and take the reciprocal.

Since mass = volume x density you can calculate the volume of the 120 drops.
Then if 120 drops = xx mL, how many drops per 1 mL.
You must remember that the number of drops in a mL will depend upon how the drop is added; i.e., it will be different from an eye dropper than it is from a teflon coated tip of a buret.
The OLD glass tipped buret I used years ago gave very close to 20 drops/mL. Through the years the tip was refined and it was about 25 drops/mL. With the teflon coated tips and smaller tips, it is about 30 drops/mL now.

• chem -

I would add one caveat to Bob Pursley's response. Check the density of water at the temperature of the water being dispensed by drops. The density may not be significantly different from 1.00 g/mL but it won't hurt to check it and see if it makes a difference.

## Similar Questions

1. ### acid-base titrations

For each of the following circumstances, indicate whether the calculated molarity of NaOH would be lower, higher or unaffected. Explain your answer in each case. a.the inside of the pipet used to transfer the standard HCI solution …
2. ### Chemistry

IN my experiment, I was doing a qualitative analysis of Group I and II anions using a flowchart. IN the chart I added 5 drops of 0.1M AgNO3 and several drops of 3M HNO3 to 5 drops of solution and found that a precipitate was formed. …
3. ### chemistry

what is the ration of water drops to EDTA (ethylenediamene tetraacetic acid) if 3 drops of EDTA was needed to change the color of 20 drops of water with known hardness?
4. ### chemistry

what is the ratio of water drops to EDTA if 2 drops of EDTA was needed to change the color of 20 drops of water with unknown hardness?
5. ### chemistry

A student is given 3 beakers: Beaker 1- 50.0 ml of a solution produced by dissolving 6.00 grams of a weak monoprotic acid ,HX, in enough water to produce 1 liter of solution. The empirical formula of HX is CH2O. The solution contains …
6. ### math

Tess adds 16 drops of yellow food coloring to a batch of frosting. This is 4 times the number of drops of red food coloring she added. Write an equation that shows how to find the number,r, of drops of red food coloring Tess added.
7. ### Chemistry

A 1.0-mL volume of 0.010 M H2SO3 is added to a mixture of 12 drops of 0.010 M HIO3, 8 drops of deionized water, and 1 drop of starch solution. a color change occured after 40 seconds. assuming 25 drops per mL for all solutions, determine …
8. ### Chem

Depending upon the tip of a dropper pipet, there are approximately 20 drops per milliliter of water. The experimental procedure indicates the addition of 5-10 drops of each solution to the test tubes. Calculate the volume range in …
9. ### Chemistry

A 1.0 mL volume of 0.010 M H2SO4 is added to a mixture of 6 drops of 0.010 M HIO3, 14 drops of deionized water, and 1 drop of starch solution. A color change in the reaction mixture occurred after 56 seconds. a. Assuming 20 drops per …
10. ### Chemistry 112

Calculate the MnO4- concentration of the diluted sample when the sample is prepared in the following manner: Add 2 drops oxalic acid, 4 drops permanganate and 8 drops water. The original permanganate is 0.25M. I don't understand how …

More Similar Questions