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3 years ago

12

The equation for the pH of a substance is pH = –log[H+], where H+ is the concentration of hydrogen ions. What is the approximate

pH of a solution whose hydrogen ion concentration is 2*10^-9
A. 1.0
B. 2.9
C. 8.7
D. 9.3

2 answers:

wariber [46]3 years ago

6 0

Answer:

ANSWWER IS C.8.7

Step-by-step explanation:

I JUST TOOK THE TEST

Korolek [52]3 years ago

5 0

PH = -log[H+]
= -log(2*10^-9)
= -(log(2) +log(10^-9))
= -(0.3 -9)
= 8.7

The appropriate choice is
C. 8.7

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Answer:

Part 1) r=5 units (see the explanation)

Part 2) $(x-4)^2+(y-7)^2=25$

Part 3) The center of the circle is (-3,4) and the radius is 4 units

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Step-by-step explanation:

Part 1)

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Find the center of circle C_1

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The distance between the center and point (0,4) is equal to the radius

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Find the radius of circle C_1

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$r=\sqrt{(7-4)^{2}+(4-0)^{2}}$

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Find the equation of the circle C, in standard form.

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The equation of a circle in standard form is

$(x-h)^2+(y-k)^2=r^2$

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we have

$x^2+y^2+6x-8y+9=0$

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nirvana33 [79]

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