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Dahasolnce [82]
3 years ago
9

Which sample contains a total of 3.0 x 10^23 molecules?

Chemistry
1 answer:
belka [17]3 years ago
3 0
Given that 1 mole contains 6.02x10^23 molecules, 3.0x10^23 is just around half a mole. Then we check the number of moles for each choice:

A. This is approximately half a mole, since the molar mass of Br2 is 159.8 g/mol.
B. He has a molar mass around 4 g/mol, so this is 1 mole.
C. H2 has a molar mass of 2.02 g/mol, so this is 2 moles.
D. Li has a molar mass of around 6.97 g/mol, so this is around 2 moles.

Therefore the only choice that fits is A. 80 g of Br2.
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A student performs a titration on 25.0 mL of 0.500M HCL(aq) which is placed in an Erlenmeyer flask. Two drops of indicator are a
Leviafan [203]

Answer:

The unknown NaOH base has a concentration of 0.636M

Explanation:

<u>Step 1:</u> the balanced equation

NaOH + HCl → NaCl + H2O

This means for 1 mole of NaOH consumed there is 1 mole of HCl needed to produce 1 mole of NaCl and 1 mole of H2O

<u>Step 2</u>: Calculate moles of HCl used

Number of moles = Concentration *  volume =  0.5M * 25*10^-3 L =0.0125 moles

<u>Step 3</u>: Calculate moles of NaOH

Since the mole ratio for HCl and NaOH is 1:1 this means we have 0.0125 moles of NaOH for 0.0125 moles of HCl

<u>Step 4:</u> Calculate Concentration of  the unknown NaOH base

Concentration = Number of moles / Volume

Volume of NaOH = 24.64-5 =19.64 mL = 0.01964 L

Concentration = 0.0125/0.01964 = 0.636 M

The unknown NaOH base has a concentration of 0.636M

8 0
3 years ago
You are given the following three half-reactions:(1) Fe³⁺(aq) + e⁻ ⇄ Fe²⁺(aq) (2) Fe²⁺(aq) +2e⁻ ⇄ Fe(s) (3) Fe³⁺(aq) +3e⁻ ⇄ Fe(s
RideAnS [48]

The E°half-cell of the (3) is 0.33 volts .

Given,

(1)  Fe3+(aq) +e =Fe2+(aq)

(2) Fe2+(aq) +2e = Fe(s)

(3) Fe3+(aq) +3e = Fe(s)

We know ,

E° half-cell of (1) is 0.77 volts .

E° half cell of ( 2) is -0.44 volts .

By resolving or adding equation 1 and 2 we will get (3) ,

Thus , the value of the E° half cell of (3) is given by ,

E°cell = E° half-cell of (1 ) + E° half-cell of (2 ) = 0.77-0.44 = 0.33 volts

Hence the E° half-cell of ( 3 ) is 0.33 volts .

<h3>What is cell potential? </h3>

It is the difference between the electrode potentials of two half cells.

it also defined as the force which causes the flow of electrons from one electrode to the another and thus results in the flow of current.

Ecell = E( cathode) - E ( anode)

<h3>What is electrode potential ? </h3>

The tendency of the electrode to lose of gain electrons is called as electrode potential.

Learn more about cell potential here :

brainly.com/question/19036092

#SPJ4

4 0
1 year ago
How humans can improve the negative aspects of soil use FULL SENTENCES 50 POINTS PLEASE HELP
katen-ka-za [31]

Answer:

Using diverse nutrient sources can help maintain soil health. Manure and compost add organic matter as well as an array of nutrients, but using just compost or manure to meet the nitrogen needs of the crop every year can result in excessive phosphorus levels in the soil.

5 0
2 years ago
Which elements are considered metals? Non-metals? Metalloids?
kolbaska11 [484]

The answer is in the photo.

3 0
2 years ago
If you dilute 19.0 mL of the stock solution to a final volume of 0.310 L , what will be the concentration of the diluted solutio
Dahasolnce [82]

Answer:

M_2=0.613M_1

Explanation:

M_1 = Concentration of stock solution

M_2 = Concentration of solution

V_1 = Volume of stock solution = 19 mL

V_2 = Volume of solution = 0.31 L= 310 mL

We have the relation

M_1V_1=M_2V_2\\\Rightarrow M_2=\dfrac{M_1V_1}{V_2}\\\Rightarrow M_2=\dfrac{M_119}{310}\\\Rightarrow M_2=M_1\times\dfrac{19}{310}\\\Rightarrow M_2=0.613M_1

\boldsymbol{\therefore M_2=0.613M_1}

The concentration of the diluted solution will be 0.613 times the concentration of the stock solution.

6 0
3 years ago
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