Wednesday
June 19, 2013

# Posts by Sara

Total # Posts: 3305

chemistry
a student dissolves 80 mg of a crude product in 4.5 mL( the minimum required) of methanol at 25 deg C . She cools the solution in an ice bath and obtains crystals. The crystals are recovered by filtration and rinsed with 0.5 mL of ice-cold methanol. After drying, the weight of...

calculus
Find the integral of (tan x)^2 sec(x)dx

calculus
Find the integral of: dx/(x^2-4x)

chemistry
I got x= 8.88 g the second extraction you mean the same solve, that means I should do 8.88+8.88= total of z?

chemistry
Suppose a compound Z had a partition coefficient of 8.0 in ether-water. If 10.0 g of Z was dissolved in 100 mL of water, and if the water solution was extracted with two 100 mL portions of ether, answer the following questions. show your calculation. a) What is the total amoun...

Chemistry
what conditions are shared by cities that suffer from photochemical smog?

Chemistry
54.0 mL of a 1.50 M solution is diluted to a total volume of 258 mL. A 129-mL portion of that solution is diluted by adding 165 mL of water. What is the final concentration?

PHYSICS
Because Earth's rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 93 centuries, what is the total (in hours) of the daily increases in time (that is, the sum of t...

PHYSICS
Grains of fine California beach sand are approximately spheres with an average radius of 50 μm and are made of silicon dioxide, which has a density of 2.4 × 103 kg/m3. What mass of sand grains would have a total surface area (the total area of all the individual sph...

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