What term BEST describes this mineral's luster?<br><br> A. waxy<br> B. shiny<br> C. glassy

Potassium thiocyanate, KSCN, is often used to detect the presence of Fe3+ ions in solution through the formation of the red Fe(H

Natalija [7]

Answer:

Ferric ions left in the solution at equilibrium is $8.0\times 10^{-6} M$ .

Explanation:

Moles of ferric nitrate in 0.700 L = n

Volume of the solution = V = 0.700 L

Molarity of ferric nitrate = M = 0.00150 M

$n=M\times V=0.00150 M\times 0.700 L=0.00105 mol$

Moles of potassium thiocyanate in 0.700 L = n'

Volume of the potassium thiocyanate solution = V' = 0.700 L

Molarity of potassium thiocyanate = M' = 0.200 M

$n'=M'\times V'=0.200 M\times 0.700 L=0.140 mol$

Molarity of ferric ions after mixing :

1 mol of ferric nitrate gives 1 mol of ferric ions.Then 0.00105 mol ferric nitrate will :

Moles of ferric ions = 0.00105 mol

$M_1=\frac{0.00105 mol}{0.700 L+0.700 L}=0.00075 M$

Molarity of thiocyanate ions after mixing :

1 mol of potassium thiocyanate gives 1 mol of thiocyanate ions.Then 0.140 mol potassium thiocyanate will give:

Moles of thiocyanate ions = 0.140 mol

$M_2=\frac{0.140 mol}{0.700 L+0.700 L}=0.1 M$

Complex equation:

$Fe^{3+}+SCN^-\rightleftharpoons [Fe(SCN)]^{2+}$

0.00075 M 0.1 M 0

At equilibrium:

(0.00075 M -x) (0.1 M-x) x

The formation constant of the given complex = $K_f=8.9\times 10^2$

$K_f=\frac{[[Fe(SCN)]^{2+}]}{[[Fe^{3+}]][SCN^{-}]}$

$8.9\times 10^2=\frac{x}{(0.00075 M -x)\times (0.1 M-x)}$

Solving for x:

x = 0.000742 M

Ferric ions left in the solution at equilibrium :

= (0.00075 M -x) = (0.00075 M - 0.000742 M)= $8.0\times 10^{-6} M$

5 0

2 years ago

Your sick puppy is diagnosed with roundworms. They grow inside of the puppy. What type of symbiotic relationship do the puppy an

Ratling [72]

D. Parasitism , the roundworm benefits from the relationship, but the puppy is harmed

4 0

2 years ago

What volume of water is produced when 38.5 g of ethanol reacts with oxygen at 500°C at 1.75 atm?

tensa zangetsu [6.8K]

Answer:

90.99 or 91.0

Explanation:

Using the balanced equation, you convert 38.5g of ethanol to moles of water. From there, you plug the values into the Ideal Gas Equation: PV=nRT.

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3 0

2 years ago

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What is the charge on Pb in Pb(SO3)2

Maslowich

The charge on Pb in Pb(SO3)2 is Lead (IV) Sulfite.

7 0

2 years ago

NaBr + CaF2 → NaF + CaBr2 What coefficients are needed to balance the chemical equation? A) 1,1,1,1 B) 1,2,1,2 C) 1,2,2,1 D) 2,1

elena-s [515]

D.
2NaBr + CaF2 --> 2NaF + CaBr2 gives you:

2Na 2Na
2Br 2F
1Ca 1Ca
2F 2Br

This is balanced.

7 0

2 years ago

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What term BEST describes this mineral's luster? A. waxy B. shiny C. glassy