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melisa1 [442]
3 years ago
6

A sample of river water taken near a factory shows pH 5. Does this represent a pollution problem?

Chemistry
1 answer:
melomori [17]3 years ago
3 0

Yes because a pH below 7 is acidic and that means that there is pollution

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Two chemicals A and B are combined to form a chemical C. The rate, or velocity, of the reaction is proportional to the product o
stiv31 [10]

Answer:

Follows are the solution:

Explanation:

A + B = C

Its response decreases over time as well as consumption of a reactants.  

r = -kAB

during response A convert into 2x while B convert into x to form 3x of C

let's  y = C

y = 3x

Still not converted sum of reaction  

for A: 100 - 2x

for B: 50 - x

Shift of x over time  

\frac{dx}{dt} = \frac{-k(100 - 2x)}{(50 - x)}

Integration of x as regards t  

\frac{1}{[(100 - 2x)(50 - x)]} dx = -k dt\\\\\frac{1}{2[(50 - x)(50 - x)]} dx = -k dt\\\\\ integral\  \frac{1}{2[(50 - x)^2]} dx =\ integral [-k ] \ dt\\\\\frac{-1}{[100-2x]} = -kt + D \\\\

D is the constant of integration

initial conditions: t = 0, x = 0

\frac{-1}{[100-2x]} = -kt + D   \\\\\frac{ -1}{[100]} = 0 + D\\\\D= \frac{-1}{100}\\\\

hence we get:

\frac{-1}{[100-2x]}= -kt -\frac{1}{100}\\\\or \\\\ \frac{1}{(100-2x)} = kt + \frac{1}{100}

after t = 7 minutes , C = 10 \ g = 3x

3x = 10\\\\x = \frac{10}{3}

Insert the above value x into \frac{1}{(100-2x)} equation = kt + \frac{1}{100} to get k.  

\to  \frac{1}{(100-2\times \frac{10}{3})}  = k \times (7) + \frac{1}{100} \\\\ \to  \frac{1}{(100- 2 \times 3.33)} =   \frac{700k + 1}{100} \\\\ \to  \frac{1}{(100-6.66)} = \frac{700k + 1}{100}\\\\ \to \frac{1}{93.34} = \frac{700k + 1}{100} \\\\

\to 100 =  93.34(700k + 1) \\\\ \to 100 =  65,338k + 700 \\\\ \to   65,338k =  -600 \\\\ \to  k =  \frac{-600}{ 65,338} \\\\ \to k= - 0.0091

therefore plugging in the equation the above value of k  

\to \frac{1}{(100-2x)} = kt +\frac{1}{100} \\\\\to \frac{1}{(100-2x)} = -0.0091t + \frac{1}{100}\\\\\to \frac{1}{(100-2x)} =  \frac{1 -0.91t}{100}\\\\\to \frac{1}{2(50-x)} =  \frac{1 -0.91t}{100}\\\\\to \frac{1}{(50-x)} =  \frac{1 -0.91t}{50}\\\\\to 50= (1-0.91t)(50-x)\\\\\to 50 = 50-45.5t-x-0.91tx\\\\\to x+0.91xt= -45.5t\\\\\to x(1+0.91t)= -45.5t\\\\\to x=\frac{-45.5t}{1+0.91t}

Let y = C

, calculate C:

y = 3x

y =3 \times \frac{-45.5t}{1+0.91t}

amount of C formed in 28 mins

x = \frac{-45.5t}{1+0.91t} , plug t = 28

\to x = \frac{-1274}{1+25.48} \\\\\to x = \frac{-1274}{26.48} \\\\\to x= -48.26

therefore amount of C formed in 28 minutes is = 3x = 144.78 grams

C: y =3 \times \frac{-45.5t}{1+0.91t}

y= 136.5 =137

7 0
3 years ago
9) What is the density of the gold rock with a mass of 386 grams and has a volume of 20 cubic centimeters?
miss Akunina [59]

Answer:

density= mass/volume

hence density of gold rock

= 386/20

=19.3 g/cc

3 0
3 years ago
Word equation of nitrogen + oxygen —--> ammonia
katrin [286]

Answer:

it is ammonia nitro oxide

5 0
3 years ago
Read 2 more answers
Which of the following reagents is/are likely to be used to form the Britton–Robinson buffer solution used in the experiment?
Ierofanga [76]

Answer:

I. A polyprotic, weak acid

II. Na2HPO4

Explanation:

Buffer solutions are those that, upon the addition of an acid or base, are capable of reacting by opposing the part of the basic or acid component to keep the pH fixed.

Buffers consist of hydrolytically active salts that dissolve in water. The ions of these salts are combined with acids and alkalis. These hydrolytically active salts are the products that result from the reaction between weak acids and strong alkalis such as calcium carbonate (from carbonic acid and calcium hydroxide) or between strong acids and weak alkalis such as ammonium chloride (a from hydrochloric acid and ammonium hydroxide).

A buffer acid reacts when a weak acid or weak base is combined with its corresponding hydrolytic salt in a water solution, a buffer system called a buffer is formed. As in this case a weak polyrotic acid with Na2HPO4, which allows the solution to be maintained at a pH of 3.8 against small aggregate amounts of both acid and base, thus favoring the reaction at a pH of 3.8

A buffer system is not always appropriate, because the ions of some hydrolytic salts can, for example, damage organisms that come into contact with it.

4 0
3 years ago
How does frost form?
hram777 [196]

Answer:

Frost forms when an outside surface cools past the dew point.

Example: The dew point is the point where the air gets so cold, the water vapor in the atmosphere turns into liquid. This liquid freezes. If it gets cold enough, little bits of ice, or frost, form.

3 0
3 years ago
Read 2 more answers
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