What is the name of the ionic compound RbCI?

A standard solution of FeSCN2+ is prepared by combining 9.0 mL of 0.20 M Fe(NO3)3 with 1.0 mL of 0.0020 M KSCN . The standard so

Xelga [282]

Answer : The equilibrium concentration of $SCN^-$ in the trial solution is $4.58\times 10^{-8}M$

Explanation :

First we have to calculate the initial moles of $Fe^{3+}$ and $SCN^-$ .

$\text{Moles of }Fe^{3+}=\text{Concentration of }Fe^{3+}\times \text{Volume of solution}$

$\text{Moles of }Fe^{3+}=0.20M\times 9.0mL=1.8mmol$

and,

$\text{Moles of }SCN^-=\text{Concentration of }SCN^-\times \text{Volume of solution}$

$\text{Moles of }SCN^-=0.0020M\times 1.0mL=0.0020mmol$

The given balanced chemical reaction is,

$Fe^{3+}(aq)+SCN^-(aq)\rightleftharpoons FeSCN^{2+}(aq)$

Since 1 mole of $Fe^{3+}$ reacts with 1 mole of $SCN^-$ to give 1 mole of $FeSCN^{2+}$

The limiting reagent is, $SCN^-$

So, the number of moles of $FeSCN^{2+}$ = 0.0020 mmole

Now we have to calculate the concentration of $FeSCN^{2+}$ .

$\text{Concentration of }FeSCN^{2+}=\frac{0.0020mmol}{9.0mL+1.0mL}=0.00020M$

Using Beer-Lambert's law :

$A=\epsilon \times C\times l$

where,

A = absorbance of solution

C = concentration of solution

l = path length

$\epsilon$ = molar absorptivity coefficient

$\epsilon$ and l are same for stock solution and dilute solution. So,

$\epsilon l=\frac{A}{C}=\frac{0.480}{0.00020M}=2400M^{-1}$

For trial solution:

The equilibrium concentration of $SCN^-$ is,

$[SCN^-]_{eqm}=[SCN^-]_{initial}-[FeSCN^{2+}]$

$[SCN^-]_{initial}$ = 0.00050 M

Now calculate the $[FeSCN^{2+}]$ .

$C=\frac{A}{\epsilon l}=\frac{0.220}{2400M^{-1}}=9.17\times 10^{-5}M$

Now calculate the concentration of $SCN^-$ .

$[SCN^-]_{eqm}=[SCN^-]_{initial}-[FeSCN^{2+}]$

$[SCN^-]_{eqm}=(0.00050M)-(9.17\times 10^{-5}M)$

$[SCN^-]_{eqm}=4.58\times 10^{-8}M$

Therefore, the equilibrium concentration of $SCN^-$ in the trial solution is $4.58\times 10^{-8}M$

5 0

3 years ago

Oxygen atoms have six outer electrons<br><br> Write the symbol for an oxide ion.

Shkiper50 [21]

Answer:

$O^{2-}$ is the symbol for an oxide ion

7 0

3 years ago

5. What is the partial pressure of the remaining gas, if the total is 384 torr 2

alexgriva [62]

Answer: 83.11 torr

Explanation:

According to Dalton's Law of partial pressure, the total pressure of a mixture of gases is the sum of the pressure of each individual gas.

i.e Ptotal = P1 + P2 + P3 + .......

In this case,

Ptotal = 384 torr

P1 = 289 torr

P2 = 11.89 torr

P3 = ? (let the partial pressure of the remaining gas be Z)

Ptotal = P1 + P2 + Z

384 torr = 289 torr + 11.89 torr + Z

384 torr = 300.89 torr + Z

Z = 384 torr - 300.89 torr

Z = 83.11 torr

Thus, the partial pressure of the remaining gas is 83.11 torr.

5 0

4 years ago

Why do we need to be more careful of how we use our water

Reil [10]

That's why it's important for you to use water wisely and not to waste it. When you waste water, you're taking water that other people might need. But when you use water carefully, you leave more water for other people to use. It is also important to use water carefully because our weather can be unpredictable.

3 0

3 years ago

Read 2 more answers

Make a checklist of eight good characteristics of a experiment.

natka813 [3]

I could only find 7!

- independent variable
- dependent variable
- control group
- experimental group
- constant
- observation
- inference

6 0

3 years ago