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If two electrons are each 1.50x10^(-10) m from a proton, find the magnitude and direction of the net electric force they will exert on the proton.

Two large, parallel, metal plates carry opposite charges of equal magnitude. They are separated by 50.0 mm, and the potential difference between them is 365 V. What is the magnitude of the electric field (assumed to be uniform) in the region between the plates?

An object is placed 24 cm in front of a concave mirror with a focal length of 6.0 cm. If the

image formed is 4.0 cm long, where is the image formed and how tall is the object?

The plates of a parallel-plate capacitor are 2.50 mm apart, and each carries a charge of magnitude 80.0 nC. The plates are in vacuum. The electric field between the plates has a magnitude of 4.00 X 10 6 V/m

(a) What is the potential difference between the plates?
(b) What is the area of each plate?

(c) What is the capacitance?

 Two billiard balls (same mass) undergo a collision as shown in the figure below. Ball 1 is initially traveling along +x  direction with a speed of 10.0 m/s, and ball 2 is at rest. After the collision, ball 1 moves away with a speed of 8.20 m/s at  an angle of 22.0°. 

1. a) What angle does the final velocity of ball 2 make with the +x axis? 
2. b) Find the speed of ball 2 after the collision. 
3. c) Was the kinetic energy conserved in this collision?

How do I approach this and solve it. Help

6. A satellite in a circular orbit experiences a centripetal acceleration of . The tangential speed of the satellite is . What is the altitude of the satellite?  

While on a visit to Minnesota (Land of 10000 Lakes), you sign up to take an excursion around one of the larger lakes. When you go to the dock where the 1500kg boat is tied, you find that the boat is bobbing up and down in the waves, executing simple harmonic motion with amplitude 20cm. The boat takes 3.5s to make one complete up-and-down cycle. When the boat is at its highest point, its deck is at the same height as the stationary deck. As you watch the boat bob up and down, you (mass 60kg) begin to feel a bit woozy, due in part to the previous night's dinner of lutefisk. As a result, you refuse to board the boat unless the level of the boat's deck is within 10cm of the deck level. How much time do you have to board the boat comfortably during each cycle of the up-and-down motion?

Potassium permanganate, a strong oxidizing agent, is commonly used in titrations because of its significant purple hue in solution. An experiment was performed in which a sample of iron(II) chloride (FeCl2) was dissolved in water and titrated with potassium permanganate (KMnO4) according to the following balanced equation. KMnO4(aq) + 8 HCl(aq) + 5 FeCl2(aq) → MnCl2(aq) + 5 FeCl3(aq) + 4 H2O(l) + KCl(aq) If 28.64 mL of 0.1110 M KMnO4 was added to the solution to reach the end point, what mass of FeCl2 was in the sample?

Just an idea on how to start this. thank you Experiment 6

Titrations with KMnO4 

Introduction:

Potassium permanganate is a strong oxidizing agent as indicated by its large positive standard reduction potential value of 1.507 volts in acid medium.

MnO4−  +    8 H+   + 5e- ⎯→ Mn2+   +4 H2O E°  =  1.507 V

In titrimetric analysis, it is frequently used as titrant due to its intense coloring power, which requires no auxiliary indicator.  When the titration is carried out in acidic medium, the permanganate ion is reduced to the colorless manganous ion (Mn2+) in aqueous solution.  A drop of excess permanganate turns the solution into pink color, which could last for about 15 seconds. This color is taken as the endpoint of the titration.  The solution must be kept inside a brown bottle because it readily decomposes to brown MnO2 upon reaction with sunlight.  

Direct titration with KMnO4 is an analytical procedure commonly used by analysts because it does not require the use of an auxiliary indicator.  Samples that contain Fe2+ react quantitatively with KMnO4 in cold, acid solution but reaction with oxalate ion occurs quantitatively in hot, acid solution.  A commercial sample of hydrogen peroxide can also be analyzed by direct titration where the H2O2 present in the sample is oxidized to O2.   Commercial samples of hydrogen peroxide are encountered as aqueous solutions of containing about 6%-30% (w/v) H2O2.  A more common way of expressing the composition of these commercial products is by indicating the volume of oxygen liberated when the solution undergoes decomposition by boiling according to the equation written below:  :

2H2O2(aq)   ⎯⎯→  2H2O(l)  +  O2(g)

Thus 1 mL of a sample of hydrogen peroxide with the label 20-volume will yield 20 mL of O2 measured at standard temperature and pressure (STP).  The label 20-volume refers to a 6% (w/v) H2O2, 40-volume is also 12% (w/v) H2O2, and 100-volume hydrogen peroxide refers to 30% (w/v) H2O2.  For the procedure described below, the suitable samples to use labeled as 10-volume or 20-volume H2O2.

Experimental Procedure

• Preparation of a 0.02 M Potassium Permanganate.

Weigh approximately 1.6-g of a good grade potassium permanganate and place it in a 250-mL beaker. Dissolve the salt by adding 50-mL of water and stirring. Decant the solution into a large beaker and add 50-mLof additional water to dissolve the crystals remaining in the first beaker. Repeat this procedure until all crystals are dissolved. Dilute the solution to about 0.5 L, transfer to a glass-stoppered bottle and label properly.

Note: Consult the lab instructor if the treatment procedure described below is necessary.  

To remove MnO2 proceed as follows: Before transferring the solution to the bottle, heat it just to boiling and keep it slightly below the boiling point for 1 hour. Allow the solution to cool, filter it through a sintered glass crucible using suction and transfer the solution to a glass-stoppered bottle.  

• Standardization of Potassium Permanganate Solution (McBride Method)

Accurately weigh three samples of about 0.20 to 0.25-g each of dried sodium oxalate into clean 250-mL Erlenmeyer flask.  Dissolve each sample in about 75-mLof 0.75 M H2SO4.  Then heat the first solution to almost boiling point (80 to 90oC) and titrate slowly with the permanganate through constant swirling.  The endpoint is marked by the appearance of a faint pink color that persists for 30 seconds.  The temperature should not drop below 60oC during titration.  Titrate the two other solutions in the same manner.

Add permanganate solution dropwise to about 100-ml of 0.75M H2SO4 until the color matches that of the titrated solution. This volume should be subtracted from the volume used in the titration.

Report the molarity of the permanganate solution.

Note:  

1. Aqueous solutions of 0.75 M H2SO4 can be prepared by mixing 20 mL of concentrated H2SO4 in 400 mL distilled water.  
2. Rapid titration can lead to the formation of a brown precipitate, MnO2.  The persistent appearance of the brown color precipitate will introduce error to the standardization.  
3. Maintain the temperature range required for the reaction.

• Preparation of the Impure Sample Containing Ferrous Ammonium Sulfate 

Each group will be given an unknown based on your Group No.  Weigh each of the unknown samples by difference and transfer each one into a dry flask.  Record the mass (g) of the unknown obtained for each trial.  Dissolve the unknown in 75 mL of 0.75M H2SO4 and titrate with the permanganate solution with constant swirling until the appearance of a faint pink color for about 30 sec.  

Repeat the same procedure with the other 2 samples.  

Report the composition of your sample in terms of % Fe(NH4)2(SO4)2·6H2O

• Determination of Hydrogen Peroxide 

For this experiment a 10-volume H2O2 sample is an appropriate to use.  

Transfer a 25 mL aliquot of the sample to a 500 mL volumetric flask and dilute to the mark.  Label this as dilute sample solution.  Measure a 25 mL aliquot portion of the dilute sample solution and transfer into an Erlenmeyer flask.  Add 20 mL of distilled water, 20 mL of dilute H2SO4 solution (1:5 dilution) and titrate with 0.02 M KMnO4 to the first permanent faint pink color.  Repeat the titration to two consecutive determinations and the trials should agree within 0.1 mL. 

Express the concentration of the sample in terms of %(w/v) H2O2.  

 Experiment 6:  Data & Calculations 

Titrations with KMnO4 

Table 1.  Standardization of 0.02 M KMnO4 Against the Primary Standard Sodium Oxalate

Balanced Chemical Equation:

Details

Trial 1

Trial 2

Trial 3

Mass (g) of container plus Na2C2O4

-

-

-

Mass (g) container less Na2C2O4

-

-

-

Mass (g) Na2C2O4

0.2278

0.2014

0.2070

Amount (mmoles) Na2C2O4

Amount (mmoles) KMnO4 reacted with Na2C2O4

Final Buret Reading

-

-

-

Initial Buret reading

-

-

-

Volume (mL) of the KMnO4 Solution Delivered

34.10

30.10

30.70

Molarity of KMnO4 Solution

Average Molarity of KMnO4 Solution

Deviation

Standard Deviation

Coefficient of Variation (%RSD)

Table 2.  Analysis of an Impure Sample of Ferrous Ammonium Sulfate Hexahydrate

Balanced Chemical Equation:

Details

Trial 1

Trial 2

Trial 3

Mass (g) of packet plus sample

-

-

-

Mass (g) of packet less sample

-

-

-

Mass (g) sample

1.0320

1.1038

0.9750

Average Molarity of KMnO4 solution

Final Buret Reading

-

-

-

Initial Buret reading

-

-

-

Volume (mL) of the KMnO4 Solution Delivered

18.33

19.60

17.33

Amount (mmoles) KMnO4 needed to reach the end point

Amount (mmoles) Fe2+ reacted with KMnO4

Amount (mmoles) Fe(NH4)2(SO4)2⋅6H2O 

Mass (g) Fe(NH4)2(SO4)2⋅6H2O  present in the sample

Mass Percent Fe(NH4)2(SO4)2⋅6H2O,

%Fe(NH4)2(SO4)2⋅6H2O

Average %Fe(NH4)2(SO4)2⋅6H2O

Deviation

Standard Deviation

Coefficient of Variation (%RSD)

Table 3.  Determination of H2O2 in a Commercial Sample

Balanced Chemical Equation:

Details

Trial 1

Trial 2

Trial 3

A.  Preparation of the Dilute Sample Solution

Volume (mL) of Liquid Commercial Sample

25.00

Volume (mL) of Dilute Sample Solution

500.00

B.  Titrimetric Analysis of the Sample Solution

Volume (mL) of DSS Titrated

25.00

25.00

25.00

Average Molarity of KMnO4 solution

Final Buret Reading

-

-

-

Initial Buret reading

-

-

-

Volume (mL) of the KMnO4 Solution Delivered

23.60

23.50

23.40

Amount (mmoles) KMnO4 needed to reach the end point

Amount (mmoles) H2O2 present in the aliquot portion of DSS

Total Amount (mmoles) H2O2 dissolved in the entire DSS

Total Mass (g) H2O2 dissolved in the entire DSS

% (w/v) H2O2 in the Commercial Sample

Average %(w/v) H2O2

Deviation

Standard Deviation

Coefficient of Variation (%RSD)