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3 years ago

Give the formula of a reagent which will form a

Chemistry

1 answer:

Sloan [31]3 years ago

5 0

Answer:

The group reagent is H2S in the presence of NH4Cl .

Explanation:

Mn is fourth group radical in qualitative analysis ;

the group reagent is H2S in the presence of NH4Cl .

then Mn precipitates as buff coloured sulphide , which is soluble in HCl .

MnS + 2HCl ---------> MnCl2 + H2S

on heating the solution with NaOH with bromine water, manganesedioxide gets precipitated.

MnCl2 + 2NaOH --------> Mn(OH)2 + 2NaCl

Mn(OH)2 + O -------> MnO2 + H2O

whereas NiS is insoluble in HCl. the nickel chloride gives a scarlet red precipitate with dimethy gly oxime.

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The rate constant for the second-order reaction 2NOBr(g) ¡ 2NO(g) 1 Br2(g) is 0.80/M ? s at 108C. (a) Starting with a concentrat

Valentin [98]

Answer:

(a)

$0.0342M$

(b)

$t_{1/2}=17.36s\\t_{1/2}=23.15s$

Explanation:

Hello,

(a) In this case, as the reaction is second-ordered, one uses the following kinetic equation to compute the concentration of NOBr after 22 seconds:

$\frac{1}{[NOBr]}=kt +\frac{1}{[NOBr]_0}\\\frac{1}{[NOBr]}=\frac{0.8}{M*s}*22s+\frac{1}{0.086M}=\frac{29.3}{M}\\$

$[NOBr]=\frac{1}{29.2/M}=0.0342M$

(b) Now, for a second-order reaction, the half-life is computed as shown below:

$t_{1/2}=\frac{1}{k[NOBr]_0}$

Therefore, for the given initial concentrations one obtains:

$t_{1/2}=\frac{1}{\frac{0.80}{M*s}*0.072M}=17.36s\\t_{1/2}=\frac{1}{\frac{0.80}{M*s}*0.054M}=23.15s$

Best regards.

8 0

3 years ago

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To calculate the density of a sample of matter,you must divide it_____ by its______.

Ymorist [56]

I think it is voulume and total mass

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3 years ago

A chemist prepares a solution of sodium carbonate by measuring out of sodium carbonate into a volumetric flask and filling the f

Vadim26 [7]

Answer:

The correct answer will be " $9.45\times 10^{-5} \ mol/L$ ".

Explanation:

We have:

Moles of solute (Na₂Co₃) = $18.9 \mu \ mol$

= $18.9\times 10^{-6}$

$1 \mu \ mol$ = $10^{-6} \ mol$

Now,

The volume of the solution will be:

⇒ $0.200 \ L$

∴ ${1 \ mL=0.001 \ L}$

The formula to find the concentration will be:

⇒ $Concentration = \frac{moles \ of \ solute \ (mol)}{Volume \ of \ solution \ (L)}$

On substituting the given values, we get

⇒ $=\frac{18.9\times 10^{-6}}{0.200}$

⇒ $=9.45\times 10^{-5} \ mol/L$

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3 years ago

Think fast! An element has 25 protons and 22 electrons. It has a charge of...

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Answer:

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Explanation:

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