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3 years ago

In the number 48.93, which digit is estimated?

Chemistry

1 answer:

Fudgin [204]3 years ago

7 0

The answer is 3.

Explanation:
It’s the last number and it can’t be 9 because then it would be 48.9 and no 3.

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To measure the amount of chlorine in a well-boring fluid, an analytical chemist adds silver nitrate solution to a sample of the

anyanavicka [17]

Answer:

c. precipitation

Explanation:

Let's consider the following balanced net ionic equation.

Cl⁻(aq) + AgNO₃(ag) ⇒ AgCl(s) + NO₃⁻ (ag)

What kind of reaction is this?

a. acid-base. No, because the reactants are not acids and bases.

b. redox. No, because all the species have the same oxidation numbers in the reactants and the products

c. precipitation. Yes, because an insoluble compound (AgCl) is produced, which then precipitates.

3 0

3 years ago

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

For which purpose do biochemists insert human genes into bacteria?

forsale [732]

Insertion of human genes into bacteria, also known as recombinant DNA technology, is used for the large scale production of human insulin, using bacteria as the insulin-producing machinery. The gene containing information for insulin production is inserted into the DNA of bacteria, which transcribe and translate it, and insulin is produced.

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3 years ago

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Why do we use commas after transition words?

ra1l [238]

Answer:

C - commas indicate a natural pause in the sentence

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2 years ago

What is the name given to the electrons in the highest occupied energy level of an atom? -anions -cations -valence electrons -or

Serhud [2]

Answer: