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Anna [14]
3 years ago
8

In the following reaction the iodide ion (I-) in HI is oxidized by the permanganate ion (MnO4-). A 5.0 mL solution of 0.20M HI r

equires 4.0 mL of KMnO4 to completely oxidize all the iodide. What is the molarity of the KMnO4 solution?
10 HI + 2 KMnO4 + 3 H2SO4 → 5 I2 + 2 MnSO4 + 8 H2O
1)0.05 M
2)0.16 M
3)0.25 M
4)0.8 M
Chemistry
1 answer:
katrin [286]3 years ago
6 0

Answer:

The molarity of the KMnO4 solution is 0.05M (option 1)

Explanation:

10 HI + 2 KMnO4 + 3 H2SO4 → 5 I2 + 2 MnSO4 + 8 H2O

This is the base.

10 moles of HI need 2 moles of KMnO4, to make 5 moles of I2 (gas)

Our solution of HI is 0,20 M which means 0,2 moles in 1 L of solution but we used 5 mL, so how many moles did we use?

Molarity . volume = Moles

0.2 moles/L  . 0.005L = 0.001 moles

Notice, we had to convert 5 mL into 0.005 L

So, let's go back to begining: 10 moles of HI need 2 moles of KMnO4.

How many moles of salt, do we need for 0.001 moles of HI.

The rule of three is:

10 moles of HI ___ need ___ 2 moles of KMnO4

0.001 moles of HI __ need ___ (0.001 . 2 ) / 10 = 0.0002 moles

This is our quantity of moles, that we need from KMnO4 but this moles are in 4 mL.

Molarity = moles / L but we can also take account molarity as mM / mL (Molarity/1000)

0.0002 moles . 1000 = 0.2 mM

0.2 mM / 4mL = 0.05 M

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Explanation:

However, producing foaming carbon dioxide gas by shaking a bottle of soda water is a physical change, while producing foaming carbon dioxide gas by combining baking soda and vinegar is a chemical change. ... Because no chemical bonds are broken and no new molecules are formed, this is a physical change in the system.

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3 years ago
Agree or disagree? Explain (2 ideas, 2 examples)
yawa3891 [41]

Answer:

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6 0
3 years ago
Determine the volume of water to be added to the nitric acid solution at a concentration of 8.61 mol / L to prepare 500 mL of th
Alex_Xolod [135]

Answer:

398 mL

Explanation:

Using the equation for molarity,

C₁V₁ = C₂V₂ where C₁ = concentration before adding water = 8.61 mol/L and V₁ = volume before adding water, C₂ = concentration after adding water = 1.75 mol/L and V₂ = volume after adding water = 500 mL = 0.5 L

V₂ = V₁ + V' where V' = volume of water added.

So, From C₁V₁ = C₂V₂

V₁ =  C₂V₂/C₁

= 1.75 mol/L × 0.5 L ÷ 8.61 mol/L

= 0.875 mol/8.61 mol/L

= 0.102 L

So, V₂ = V₁ + V'

0.5 L = 0.102 L + V'

V' = 0.5 L - 0.102 L

= 0.398 L

= 398 mL

So, we need to add 398 mL of water to the nitric solution.

6 0
3 years ago
At a certain temperature, the solubility of N2 gas in water at 4.07 atm is 95.7 mg of N2 gas/100 g water . Calculate the solubil
sertanlavr [38]

Answer: Thus the solubility of N_2 gas in water, at the same temperature, if the partial pressure of gas is 10.0 atm is 235mg/100g.

Explanation:-

The Solubility of N_{2} in water can be calculated by Henry’s Law. Henry’s law gives the relation between gas pressure and the concentration of dissolved gas.

Formula of Henry’s law,  C=k_{H}P.

k_{H}= Henry’s law constant = ?

The partial pressure (P) of N_{2} in water = 4.07 atm

\C= k_{H}\times P\\95.7mg=k_{H}\times 4.07

k_{H}=23.5

At pressure of 10.0 atm

C= k_{H}\times P\\C=23.5\times 10.0=235mg/100mg

Thus the solubility of N_2 gas in water, at the same temperature, is 235mg/100g

6 0
3 years ago
6. Calculate the molarity if 35.0 grams of KBr are dissolved in 700. ml?
olga55 [171]

Answer:

To calculate molarity, divide the number of moles of solute by the volume of the solution in liters. If you don't know the number of moles of solute but you know the mass, start by finding the molar mass of the solute, which is equal to all of the molar masses of each element in the solution added together.

Explanation:

try starting with 35.0 and dived it by the volume

8 0
3 years ago
Read 2 more answers
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