# Question #76833

##### 1 Answer

#### Explanation:

Start by converting the volume of the vessel from *liters* to *milliliters* by using the fact that

#color(blue)(ul(color(black)("1 L" = 10^3color(white)(.)"mL")))#

In your case, the vessel contains exactly

Now, you know that **drops** of water. Use this conversion factor to convert the volume of the vessel from *milliliters* to *drops*

#1.0 * 10^3 color(red)(cancel(color(black)("mL"))) * "20.0 drops"/(1.00color(red)(cancel(color(black)("mL")))) = 20.0 * 10^3color(white)(.)"drops"#

The problem tells you that you can count the drops at a rate of

#20.0 * 10^3 color(red)(cancel(color(black)("drops"))) * "1 s"/(10.0color(red)(cancel(color(black)("drops")))) = 2.00 * 10^3color(white)(.)"s"#

Finally, use the fact that

#color(blue)(ul(color(black)("1 h = 3600 s")))#

to convert the time from *seconds* to *hours*.

#2.00 * 10^3 color(red)(cancel(color(black)("s"))) * "1 h"/(3600color(red)(cancel(color(black)("s")))) = color(darkgreen)(ul(color(black)("0.56 h")))#

The answer is rounded to two **sig figs**, the number of sig figs you have for the volume of the vessel.