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Whitepunk [10]
2 years ago
5

Please help me double-check my answer: Calculate the molarity of an aqueous solution that contains 36.5g KMnO4 and has a total v

olume of 375 mL.
My answer is 0.616M but this option is not offered.
Chemistry
2 answers:
VashaNatasha [74]2 years ago
7 0

Answer:

Molarity = 0.616 M

Explanation:

Step 1: Data given

Mass of KMnO4 = 36.5 grams

Molar mass of KMnO4 =  158.03 g/mol

Volume of the solution = 375 mL = 0.375 L

Step 2: Calculate moles KMNO4

Moles KMnO4 = mass KMnO4 / molar mass KMnO4

Moles KMnO4 = 36.5 grams / 158.03 g/mol

Moles KMnO4 = 0.231 moles

Step 3: Calculate molarity of the aqueous solution

Molarity = moles / volume

Molarity = 0.231 moles / 0.375 L

Molarity = 0.616 M

The molarity is 0.616 M, your answer is correct. It must be an error in the options given.

Helen [10]2 years ago
6 0

Answer:

The answer to your question is Molarity = 0.6158, I got the same answer as you.

Explanation:

Data

Molarity = ?

Mass of KMnO₄ = 36.5 g

Total volume = 375 ml

Process

1.- Calculate the Molar mass of KMnO₄

KMnO₄ = (1 x 39.10) + (54.94 x 1) + (16 x 4)

            = 39.10 + 54.94 + 64

            = 158.04 g

2.- Calculate the moles of KMnO₄

                158.04 g of KMnO₄ ------------------- 1 mol

                  36.5 g of KMnO₄ ---------------------  x

                   x = (36.5 x 1) / 158.04

                   x = 0.231 mol

3.- Convert the volume to liters

                  1000 ml -------------------- 1 L

                    375 ml --------------------- x

                     x = (375 x 1)/1000

                    x = 0.375 L

4.- Calculate the Molarity

Molarity = moles / volume

-Substitution

Molarity = 0.231 moles / 0.375 L

Result

Molarity = 0.6158

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Reserpine is a natural product isolated from the roots of the shrub Rauwolfia serpentina. It was first synthesized in 1956 by No
liraira [26]

Answer:

  • Molality = 0.066 m
  • Molar mass = 608.36 g/mol

Explanation:

It seems the question is incomplete. However a web search us shows this data:

" Reserpine is a natural product isolated from the roots of the shrub Rauwolfia serpentina. It was first synthesized in 1956 by Nobel Prize winner R. B. Woodward. It is used as a tranquilizer and sedative. When 1.00 g reserpine is dissolved in 25.0 g camphor, the freezing-point depression is 2.63 °C (Kf for camphor is 40 °C·kg/mol). Calculate the molality of the solution and the molar mass of reserpine. "

The <em>freezing-point depression</em> is expressed by:

  • ΔT=Kf * m

We put the data given by the problem and <u>solve for m</u>:

  • 2.63 °C = 40°C·kg/mol * m
  • m = 0.06575 m

For the calculation of the molar mass:<em> Molality</em> is defined as moles of solute per kilogram of solvent:

  • 0.06575 m = Moles reserpine / kg camphor
  • 25.0 g camphor ⇒ 25.0/1000 = 0.025 kg camphor

We<u> calculate moles of reserpine:</u>

  • 0.06575 m = Moles reserpine / 0.025 kg camphor
  • Moles reserpine = 1.64x10⁻³ mol

Finally we use the mass of reserpine and the moles to calculate <u>the molar mass</u>:

  • 1.00 g reserpine / 1.64x10⁻³ mol = 608.36 g/mol

<em>Keep in mind that if the data in your problem is different, the results will be different. But the solving method remains the same.</em>

8 0
2 years ago
A quantity of 85.0 mL of 0.900 M HCl is mixed with 85.0 mL of 0.900 M KOH in a constantpressure calorimeter that has a heat capa
bogdanovich [222]

Explanation:

The given data is as follows.

         V_{1} = 85.0 ml,        M_{1} = 0.9 M

         V_{2} = 85.0 ml,        M_{1} = 0.9 M

Hence, number of moles of HCl and KOH will be the same because both the solutions have same volume and molarity.

So,     No. of moles = Molarity × Volume

                                = 0.9 M \times 0.085 L        (as 1 L = 1000 ml so, 85 ml = 0.085 L)

                                = 0.076 mol

As 1 mole gives 56.2 kJ/mol of heat of neutralization. Hence, calculate the heat of neutralization given by 0.076 moles as follows.

              56.2 kJ/mol \times 0.076 mol

                    = 4.271 kJ

or,                 = 4271 J     (as 1 kJ = 1000 J)

Therefore,    heat released = - heat of gained by calorimeter

Since, it is given that density of the solution is similar to the density of water which is 1 g/ml.

Hence,     mass of HCl = density × Volume of HCl

                                      = 1.00 g/ml × 85.0 ml

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Similarly,    mass of KOH = = density × Volume of HCl

                                      = 1.00 g/ml × 85.0 ml

                                       = 85 g

Hence, total mass of the solution = 85 g + 85 g

                                                        = 170 g

Also,                   q = mC \Delta T

                     4271 J = 170 g \times 325 J/^{o}C \times (T_{f} - 18.24)^{o}C    

                     0.0773 = T_{f} - 18.24

                    T_{f} = 18.317^{o}C  

Thus, we can conclude that final temperature of the mixed solution is 18.317^{o}C.

6 0
2 years ago
A poundal is the force required to accelerate a mass of 1 lbm at a rate of 1 ft/s2, and a slug is the mass of an object that wil
Darya [45]
Remember the formula as per the second Law of Newton: F = m*a

And also remember that the weight is the force with which the mass is attracted by the planet (or satellite in the case of the moon).

With that information you can answer the questions:

a) Weight = F = m*a

m = 175 slugs = 175 lbm

i) Earth

a = 32.17 ft/s^2

Weight on Earth = 175 lbm * 32.17 ft / s^2 = 5,629.75 poundal

ii) Moon

a = [1/6] 32.17 ft/s^2

Weight on the Moon = [1/6]*5,629.75 poundal = 938.29 poundal

b) Force = 355 poundal
m = 25.0 slug

a in m/s^2 = ?

First calculate the force in ft/s^2

F = m*a => a = F/m = 355 poundal / 25.0 slug = 14.2 ft/s^2

Conversion:

14.2 ft / s^2 * [ 0.3048 m/ft] = 4.32816 m/s^2

Answer: 4.33 m/s^2


8 0
2 years ago
What mass (g) of barium iodide is contained in 188 ml of a barium iodide solution that has an iodide ion concentration of 0.532m
Katarina [22]

Answer:

What mass (g) of barium iodide is contained in 188 mL of a barium iodide solution that has an iodide ion concentration of 0.532 M?

A) 19.6

B) 39.1

C) 19,600

D) 39,100

E) 276

The correct answer to the question is

B) 39.1  grams

Explanation:

To solve the question

The molarity ratio is given by

188 ml of 0.532 M solution of iodide.

Therefore we have number of moles = 0.188 × 0.532 M = 0.100016 Moles

To find the mass, we note that the Number of moles = \frac{Mass}{Molar Mass} from which we have

Mass = Number of moles × molar mass

Where the molar mass of Barium Iodide = 391.136 g/mol

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8 0
2 years ago
Which of the following is consistent with a spontaneous process in the forward direction?
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Answer:

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Explanation:

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Mathematically, we can express the second law of thermodynamics as follows:

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Therefore, the second law of thermodynamics tells us that a spontaneous reaction increases the entropy of the universe; that is, ΔSuniv > 0.

If we want spontaneity expressed only in terms  of the properties of the system (ΔHsys and ΔSsys), we use the following equation:

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That means that T∆Suniv >0.

This equation says that for a process carried out at constant pressure and temperature  T, if the changes in enthalpy and entropy of the system are such that <u>ΔHsys - TΔSsys  is less than zero, the process must be spontaneous.</u>

Finally, if the change in free energy is less than zero (ΔG<0), the reaction is spontaneous in the forward direction.

7 0
2 years ago
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