SOLUTION: A scientist has a beaker contain 20 mL of a solution containing 20% acid. To dilute this pure water is added. a. Write the equation for the concentration in the beaker after add

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Question 910752: A scientist has a beaker contain 20 mL of a solution containing 20% acid. To dilute this pure water is added.
a. Write the equation for the concentration in the beaker after adding n mL of water.
b. Find the concentration if 10 mL of water is added
c. How much mL of water must be added to equal 4%
d. what is the behavior as n approaches infinity, and what is the physical significance of this?
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
A scientist has a beaker contain 20 mL of a solution containing 20% acid. To dilute this pure water is added.
a. Write the equation for the concentration in the beaker after adding n mL of water.
Equation:
acid + acid = acid
0.20*20 + 0*n = x(20+n)
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b. Find the concentration if 10 mL of water is added
0.20*20 + 0*10 = x(20+10)
Multiply thru by 100 to get::
20*20 + 0 = x(3000)
x = 400/(3000
x = 13.3%
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c. How much mL of water must be added to equal 4%
0.20*20 + 0*n = 0.04(20+n)
20*20 + 0 = 4(20+n)
100 = 20+n
n = 80 ml
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d. what is the behavior as n approaches infinity, and what is the physical significance of this?
As more and more water is added the concentration approaches 0%
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Cheers,
Stan H.
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