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.


Related Questions

ANSWER ASAP
Which reacts with carbonates?
A. Bases only
B. Acids and bases
C. Neutral solutions
D. Acids only

Answers

Answer:

D. Acids only

Explanation:

A whale is swimming in the ocean. It communicates with another whale by sending out a sound. Which of the following best
describes how the sound gets to the other whale?
A.
All of the sound absorbed by water changes to heat before getting to the other whale.
В.
The sound is transmitted through water until it reaches the other whale.
C.
All of the sound is diffused in
the water until only a faint sound reaches the other whale.
.D
The sound is reflected in the water before it gets to the other whale.

Answers

Answer:

A.

The sound is transmitted through water until it reaches the other whale.

Explanation:

When one whale makes a sound, the sound is transmitted through water until it reaches the other whale. The sound causes a ripple-like effect in the water, producing waves that travel in the water. The waves are heard in all directions. This is why humans can hear the sounds animals make underwater.

The statement which best describes how the sound gets to the other whale is that all of the sounds absorbed by water change to heat before getting to the other whale. Thus, the correct option for this question is A.

How sound may transmit from one place to another?

The transmission of sounds is generally carried out through a medium in the form of waves. These sound waves involve the pattern of disturbance caused by the movement of energy.

In an aquatic environment, when one whale successfully constructs a sound, the sound is effectively transmitted through the medium that is known as water.

It remains in the form of waves until it reaches the other whale. The sound in a waveform provokes a ripple-like effect in the water and travels in the water. The waves are effectively heard in all directions.

Therefore, the correct option for this question is A.

To learn more about Transmission of sound in water, refer to the link:

https://brainly.com/question/18451537

#SPJ6

Please help
As the temperature increases, the molecular motion of the molecules decreases and it
becomes difficult to overcome the polar attractions.
a. TRUE
b. FALSE

Answers

true
step by step explanation:

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

Answers

Answer:

false

Explanation:

Craters on the Moon are caused by asteroids and meteorites colliding with the lunar surface. The Moon's surface is covered with thousands of craters. ... It also has very little geologic activity (like volcanoes) or weathering (from wind or rain) so craters remain intact from billions of years.

Deoxyribonucleic acid is also referred to as

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

acid Is the A

{DNA}

Hope that helps :)

What are the three types of protist and how are they similar and how are they different (this is science but there is no tab for it)

Answers

Answer:

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

boron phosphite
Formula please help fast please please help me please please help

Answers

Answer: The formula for boron phosphite  is  BP

Explanation:

The answer would be BP

Hope this helped!

Which of the following shows the correct order of the levels of classification form Largest to smallest

Answers

could you put the answee choicesv

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

Answers

Answer:

can you like number them please? it would make it a lot easier

Explanation:

d = 24 g/ml
v = 1200 ml
m = ?

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

Hope this helps you

In science, all ideas are not tested with evidence from the natural world.
Question 4 options:
True
False

Answers

Answer:

i belive its trrue

Explanation:

Answer:

i think its false i hope this helps

Explanation:

Hurry up as fast as possible Ill mark you brainlist

Answers

It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms.

These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.

Explain how cross cutting principles (intrusions, inclusions, faults) help to determine the relative age of a rock layer.

Answers

Answer:

The principle of cross-cutting relationships states that a fault or intrusion is younger than the rocks that it cuts through. ... So the fault must be the youngest formation that is seen. The intrusion (D) cuts through the three sedimentary rock layers, so it must be younger than those layers

Explanation:

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

a. freezing water to make ice.
b. a firework exploding.
c. breaking a glass bottle.
d. melting gold jewelry to make a gold bar.​

Answers

Answer:

b. a firework exploding

Explanation:

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:

please Help and Thanks!

Answers

The one that’s already circled in the picture (B)

A rectangular box has the following dimensions on the inside: 5 cm x 5 cm x 10 cm. What volume can the box hold, in milliliters?

- 20 mL
- 259 mL
- 25 mL
- 50 mL

Answers

Answer:

The volume in milliliters is 250mL

Explanation:

The volume of a rectangle is obtained using the equation:

Volume = Length * Width * Height

In the problem, we can take length as 5cm, width as 5cm and height as 10cm. Thus, volume of the rectangular box is:

Volume = 5cm * 5cm * 10cm

Volume = 250cm³

1mL = 1cm³.

That means the volume in milliliters is 250mL

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

Answers

Answer:

faules

Explanation:

truck it

What happens yo temperature in your layer as u you go higher in altitude?

Answers

Answer:

Temperatures decrease with increasing height as the ozone layer is left behind and the air thins out with increasing altitude. The lowest portion of the low-pressure mesosphere is heated by the warm air of the upper stratosphere. This heat radiates upward, getting less intense as altitude increases.

Explanation:

Brainliest please?

Which part of an atom is used to form bonds with other atoms?

Answers

Answer:

valence electrons

Explanation:

valence electrons

Answer:

Covalent bonding

Explanation:

Covalent bonding occurs when pairs of electrons are shared by atoms.

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).
2. 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 H (hydrogen).

Answers

Answer:

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

Explanation:

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

The correct name for P5O2 is

Answers

Answer:

phosphorous(iii) oxide

Explanation:

Hope this helps! :)

1. How much energy (in KJ) is required to convert 50.0g of ice at – 30 ˚C to
steam at130˚C.

Answers

Answer:

How much heat energy required to convert following?

How much heat energy, in kilojoules, is required to convert 47.0 g of ice at -18.0 C to water at 25.0 C ?

Specific Heat of Ice - 2.09 j/g * c

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

Q = m * Cice * Change in Temp

Q = (47.0 g)(2.09 J/g*c)(43) = 4222.6 J * 0.001 kj / j = 4.22 kj

Give an example of a trait and explain how a genetic trait is passed down from
parent to offspring in animals.
Your answer

Answers

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

Which statement about the alkali metals is correct?
A. They are usually gases.
B. They are extremely unreactive.
C. They are located in the left-most column of The Periodic Table
D. They form negative ions with a -1 charge

Answers

Answer:

its c they are located in the left most column of the periodic table

What do both plants and animal cells break down for energy?

Answers

Answer:

both plant and animal cells must break down food molecules to get energy from them

Plants and animal cells break down stores glucose & oxygen for energy.

what atoms are in Au(NO2)2​

Answers

Au, N, O ( give me brainliest please)

Please Help! I Really Really Need It!

Answers

Answer:

The picteure isnt lodeing

Explanation:

mark brainly

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

Answers

Answer:

OB sunlight

Explanation:

it grows with it

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