1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Crazy boy [7]
3 years ago
6

Hardness in groundwater is due to the presence of metal ions, primarily Mg2 and Ca2 . Hardness is generally reported as ppm CaCO

3 or mmol/L Ca2 . To measure water hardness, a sample of groundwater is titrated with EDTA, a chelating agent, in the presence of the indicator eriochrome black T, symbolized here as In. Eriochrome black T, a weaker chelating agent than EDTA, is red in the presence of Ca2 and turns blue when Ca2 is removed. redblue Ca(In)2+ + EDTA --> Ca(EDTA)^2+ + In A 50.00-mL sample of groundwater is titrated with 0.0600 M EDTA. Assume that Ca2 accounts for all of the hardness in the groundwater. If 12.00 mL of EDTA is required to titrate the 50.00-mL sample, what is the hardness of the groundwater in molarity and in parts per million of CaCO3 by mass?
Chemistry
1 answer:
Maslowich3 years ago
5 0

Answer:

  • 0.0144 M
  • 1440 ppm

Explanation:

Ca(In)²⁺ + EDTA → Ca(EDTA)²⁺ + In

We use the volume of EDTA consumed in the titration to <u>calculate the moles of Ca⁺² ions</u>:

  • 0.012 L * 0.0600 M * \frac{1molCa^{+2}}{1molEDTA} = 7.20x10⁻⁴ mol Ca⁺²

Now we <u>calculate the molarity</u>:

  • 7.20x10⁻⁴ mol Ca⁺² / 0.050 L = 0.0144 M

To calculate in ppm, we <u>use the moles of Ca⁺² and convert to mg of CaCO₃:</u>

  • 7.20x10⁻⁴ mol Ca⁺² = 7.20x10⁻⁴ mol CaCO₃
  • 7.20x10⁻⁴ mol CaCO₃ * 100g/mol * \frac{1000mg}{1g} = 72 mg CaCO₃

Finally, <u>the concentration in ppm</u> is:

  • 72 mg CaCO₃ / 0.050L = 1440 ppm
You might be interested in
A mixture of benzene and toluene has a total vapor pressure at 25°C of 45.06 mmHg. What is the partial pressure of benzene in th
SashulF [63]

Answer:

I just need points so ignore my answer and thanks

3 0
3 years ago
As electrical energy is converted into heat energy, the total amount in the system
Aleks04 [339]
<span>c. remains the same
</span>----------------------------------------------------
As electrical energy is converted into heat energy, the total amount in the system remains the same
--------------
according to law of conservation of energy
3 0
3 years ago
Read 2 more answers
Whats the atomic mass
Semmy [17]
The mass of a chemical substance is known as the atomic number or atomic mass
8 0
3 years ago
The autoignition of both ethanol and octane occurs at 363 oC. Which gas sample contains the gas molecules that have a greater av
USPshnik [31]

Answer:

See explanation

Explanation:

At the same temperature, the average kinetic energy of gases depends on the molecular mass of the gas. Hence,  given a particular temperature, lighter molecules travel faster on the average than heavier molecules.

Considering ethanol and octane, The molar mass of ethanol is 46.07 g/mol while the molar mass of octane is 114.23 g/mol. Hence, ethanol has a greater average kinetic energy than octane at the same temperature.

7 0
3 years ago
A: IF TWO ANGLES ARE SUPPLEMENTARY, THEN ONE ANGLE IS ACUTE AND ONE IS OBTUSE.
nydimaria [60]

Answer:

True or False?

Explanation:

A. False and or sometimes.

B. False and or sometimes.

What is our main objective here??????????????????

3 0
2 years ago
Other questions:
  • Consider a galvanic cell consisting of the following two redox couplesAlB+ 3e Al , Mga + 2e Mg, (ag. E® = 1.676 V ) E° = 2.356 V
    13·1 answer
  • URGENT!!!!!!! 15 POINTS!!!!!
    7·1 answer
  • A population of rabbits is separated by a mountain range. Which of the following is most likely to occur?
    10·2 answers
  • What type of van der Waals force exists between molecules of oxygen?
    14·1 answer
  • Why is it better to allow the solvent front to move almost to the top of a paper strip rather than stopping it at the halfway po
    5·1 answer
  • Which compound has both ionic and covenant bonds
    12·1 answer
  • Calcula la concentración porcentual de una disolución que se preparó disolviendo 30 g de Hidróxido de Litio en suficiente cantid
    13·1 answer
  • How many grams are needed to prepare 750. mL of a 0.35 M solution of NaOH?
    12·1 answer
  • How is a joule defined?
    12·1 answer
  • Some one have a full conversation with me I am so bored
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!