The maximum allowable concentration of Pb2+ ions in water in a local community is 1.51 x 10-8 M. Could a chemist use 2.00 mL of 0.12 M KBr solution on a 5.00 mL sample of tap water to prove through a precipitation reaction that the water supply is safe? Show all work and reasoning

Answers

Answer 1

Answer:

The water supply is not safe.

Explanation:

Ionically, the reaction is;

Pb^2+(aq) + 2Br^-(aq) -------> PbBr2(s)

Amount of Br^- reacted = 2/1000 * 0.12 = 2.4 * 10^-4 moles

From the reaction equation;

1 mole of Pb^2+ requires 2 moles of Br^- for complete precipitation

x moles of Pb^2+ requires 2.4 * 10^-4 moles of Br^-

x = 1 * 2.4 * 10^-4 /2

x = 1.2 * 10^-4 moles of Pb^2+

Concentration of Pb^2+ precipitated from 5ml of tap water =  1.2 * 10^-4 * 1000/5

Concentration = 2.4 * 10^-2 M

The amount of  Pb^2+ found in the water is greater than the maximum allowable concentration of Pb2+ ions in water in a local community which is 1.51 x 10-8 M. Therefore, the water supply is not safe.


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Answer:

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Explanation:

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Many of the lunar craters are due to volcanic eruptions true or false

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Answer:

false

Explanation:

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The energy that plants need for photosynthesis comes from
OA.
minerals,
OB. sunlight
OC.
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OD.
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Answers

Answer:

OB sunlight

Explanation:

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- 20 mL
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Answers

Answer:

The volume in milliliters is 250mL

Explanation:

The volume of a rectangle is obtained using the equation:

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When drawing a covalent lewis dot diagram its important to ensure that:
A each atom is surrounded by 6 electrons
B all symbols are in lower case letters
C all the elements have a charge in the top right side
D each atom is surrounded by 8 electrons

Answers

Answer B I believe
Not sure if it’s correct but Lina positive it is

In science, all ideas are not tested with evidence from the natural world.
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True
False

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Answer:

i belive its trrue

Explanation:

Answer:

i think its false i hope this helps

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atomic concept map. help me fill this out with the terms on the right. 40 points.

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Answer:

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Explanation:

Give an example of a trait and explain how a genetic trait is passed down from
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Your answer

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Explanation:

Parents pass characteristics such as hair color, nose shape, and skin color to their offspring. Not all of the parents' characteristics will appear in the offspring, but the characteristics that are more likely to appear can be predicted.

I'm just trying to answer questions. T^T

What is the speed of a car that has traveled 100 miles in 20 hours?
|

Answers

Answer:

5 mph

Explanation:

100 miles, 20 hours (divide by 2)

50 miles,    10 hours (divide by 2)

25 miles,    5 hours (divide by 2)

divide both sides by 5

5 miles,     1 hour

Answer:2

Explanation:

True Or False? A magnet slows down because it created an opposing electric force as it fell.

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Answer:

faules

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Answer:

They are eukaryotic, which means they have a nucleus. Most have mitochondria

d = 24 g/ml
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Answers

Answer:

28,800 g

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

mass = Density × volume

From the question we have

mass = 24 × 1200

We have the final answer as

28,800 g

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Which of the following is an example of a chemical change?

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c. breaking a glass bottle.
d. melting gold jewelry to make a gold bar.​

Answers

Answer:

b. a firework exploding

Explanation:

1, If the “R” under the group title represent the elements in that group, then how any atoms of Na (sodium) will react with 1 atom of O (oxygen).
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Answer:

NaH one atom of sodium react with one hydrogen to form sodium hydride

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Hurry up as fast as possible Ill mark you brainlist

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boron phosphite
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Answers

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Explanation:

The answer would be BP

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Answers

The answer is nucleic acid

Answer:

(DNA) is a molecule that encodes an organism's genetic blueprint

Explanation:

Deoxyribo Is the D

nucleic Is the N

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A whale is swimming in the ocean. It communicates with another whale by sending out a sound. Which of the following best
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A.
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В.
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C.
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Answers

Answer:

A.

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Explanation:

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Answers

Answer:

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ANSWER ASAP
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Answer:

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Answer:

How much heat energy required to convert following?

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This is how I did it and the answer is wrong...Please check and correct me

Q = m * Cice * Change in Temp

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