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2 years ago

Explain why sodium chloride solution cannot be used as the electrolyte to produce

Chemistry

1 answer:

ira [324]2 years ago

6 0

Explanation:

Because the solution only contains Na+ and Cl− ions, and water, and not the metal Na(s) . You cannot evaporate the water from the solution and hope to obtain anything but NaCl(s) .

Na(s) has an electron configuration of 1s^2 2s^2 2p^6 3s^1 , but Na+(aq) has an electron configuration of 1s^2 2s^2 2p^6 . That means they are not the same element, and thus, there is no straightforward way of extracting Na(s) from a NaCl (aq) solution

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a sample of 25.0g of an unknown metal is added to 25.0ml of water in a graduated cylinder and the final volume is 28.5ml what is

leva [86]

Answer:

<h2>The answer is 7.14 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question

mass of metal = 25 g

volume = final volume of water - initial volume of water

volume = 28.5 - 25 = 3.5 mL

It's density is

$density = \frac{25}{3.5} \\ = 7.142857...$

We have the final answer as

Hope this helps you

8 0

3 years ago

All the ways scientists do investigations

Eva8 [605]

Scientific metod this is one of them

3 0

3 years ago

A patient needs to take 875mg twice daily The pills in the bottle are each 250mg How many pills does she wants to take 875mg

Angelina_Jolie [31]

Answer:

$3.5$ pill need to taken for completing dosage of $875$ mg

Explanation:

Total dosage of medicine to be taken in a day

$= 2 * 875 \\= 1750$ mg

Total weight of one pill $= 250$ mg

Number of pills required is equal to total dosage of medicine divided by the weight of one pill.

Hence,

Number of pills

$= \frac{875}{250} \\= \frac{175}{50} \\= \frac{35}{10} \\= 3.5$

6 0

3 years ago

How much energy do individual photons of 470 nm light have

IceJOKER [234]

<h3>Answer:</h3>

4.227 × 10^-19 Joules

<h3>Explanation:</h3>

Energy of a photon of light is calculated by the formula;

E = hf, where h is the plank's constant, 6.626 × 10^-34 J-s and f is the frequency.

But, f = c/λ

Where, c is the speed of light (2.998 × 10⁸ m/s), and λ is the wavelength.

Given the wavelength is 470 nm or 4.7 × 10^-7 m

Therefore;

E = hc/λ

= (6.626 × 10^-34 J-s × 2.998 × 10^8 m/s) ÷ 4.7 × 10^-7 m

= 4.227 × 10^-19 Joules

Therefore, the energy of a photon with 470 nm is 4.227 × 10^-19 Joules

3 0

3 years ago

15.00 grams of Chromium react with 15.00 grams of hydrobromic acid. Calculate the theoretical yield of the reaction. At STP what

s2008m [1.1K]

Answer:

(a) 18.03 g

(b) 2.105 L

Step-by-step explanation:

We have the masses of two reactants, so this is a<em> limiting reactant problem. </em>

We know that we will need a balanced equation with masses, moles, and molar masses of the compounds involved.

<em>Step 1</em>. <em>Gather all the information</em> in one place with molar masses above the formulas and masses below them.

M_r: 52.00 80.91 291.71

2Cr + 6HBr ⟶ 2CrBr₃ + 3H₂

Mass/g: 15.00 15.00

<em>Step 2</em>. Calculate the <em>moles of each reactant</em>

Moles of Cr = 15.00 × 1/52.00

Moles of Cr = 0.2885 mol Cr

Moles of HBr = 15.00 × 1/80.91

Moles of HBr = 0.1854 mol HBr ×

<em>Step 3</em>. Identify the<em> limiting reactant</em>

Calculate the moles of CrCl₃ we can obtain from each reactant.

<em>From Cr</em>:

The molar ratio of CrBr₃:Cr is 2 mol CrBr₃:2 mol Cr

Moles of CrBr₃ = 0.2885 × 2/2

Moles of CrBr₃ = 0.2885 mol CrCl₃

The molar ratio of CrBr₃:HBr is 2 mol CrBr₃:6 mol HBr.

Moles of CrBr₃ = 0.1854 × 2/6

Moles of CrBr₃ = 0.061 80 mol CrBr₃

The limiting reactant is HBr because it gives the smaller amount of CrBr₃.

<em>Step 4</em>. Calculate the <em>theoretical yields</em> of CrBr₃ and H₂.

Theoretical yield of CrBr₃ = 0.061 80 × 291.71/1

Theoretical yield of CrBr₃ = 18.03 g CrCl₃

The molar ratio is 3 mol H₂:6 mol HBr

Theoretical yield of H₂ = 0.1854 × 3/6

Theoretical yield of H₂ = 0.092 70 mol H₂

<em>Step 5</em>. Calculate the <em>volume of H₂</em> at STP

STP is 1 bar and 0 °C.

The molar volume of a gas at STP is 22.71 L.

Volume = 0.092 70 × 22.71/1

Volume = 2.105 L

<em>Step 6</em>. Calculate the <em>percent yield </em>

% Yield = actual yield/theoretical yield × 100 %

Actual yield = 15.35 g

% yield = 15.35/18.03 × 100

% yield = <em>85.15 % </em>

8 0

3 years ago