PLEASE PLEASE HELP! CHEM!

This question is describing an spectrophotometry experiment in which the concentration of copper(II) ions has to be determined when 2.50 g of a copper-rich penny is reacted with 50.0 mL of nitric acid. In addition, the absorbance of a sample of the solution turned out to be 0.12 at 635 nm, so that the concentration was estimated as 12.8 g/L.

First of all, we must recall the Beer's law that can be written as follows:

[tex]A=ebC[/tex]

Whereas A is the absorbance of the sample, e the molar absorptivity, b the cuvette's path and C the concentration. However, this problem is not providing sufficient information to calculate the required concentration, however, similar absorbance experiments have graphed (absorbance vs concentration) calibration curves exhibiting trendlines as the one shown below:

[tex]y=0.009647x-0.003655[/tex]

Thus, since y stands for the absorbance and x for the concentration but in g/L not M (mol/L) for those experiments, we can set y equal to 0.12 so we solve for x as the concentration of the copper(II) ions in the sample:

[tex]y=0.009647x-0.003655\\\\x=\frac{0.12+0.003655}{0.009647}\\\\x=12.8g/L[/tex]

Nevertheless, it would be great if you come up with your own trendline, having clear the units for the absorbance vs concentration graph and thus double check your results because the data was not enough for the time being.

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Answer:

A

Explanation:

We are given that the molar mass of boron triflouride BF₃ is 67.81 g/mol. We want to determine the number of molecules of BF₃ in 2 g of BF₃.

Recall that there are 6.02 × 10²³ molecules in any mole of a substance. In other words, there are 6.02 × 10²³ BF₃ molecules in a mole of BF₃. Starting with the initial value, multiply:

[tex]\displaystyle \begin{aligned} 2\text{ g BF$_3$}&\cdot \frac{1\text{ mol BF$_3$}}{67.81 \text{ g BF$_3$}} \cdot \frac{6.02\times 10^{23} \text{ molecules BF$_3$}}{1 \text{ mol BF$_3$}} \\ \\ &= 1.776 \times 10^{22} \text{ molecules BF$_3$}\end{aligned}[/tex]

Hence, our answer is A.

*Perhaps it rendered the values incorrectly, but since we started with only 2 g of BF₃, our resulting calculation should only contain one significant digit. Hence, the correct answer should be 2 × 10²² molecules of BF₃.

The molecules of  BF₃ that are there in 2 g is 1.776 × 10²² molecules and the correct option is option A.

The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter.

A mole is defined as the amount of substance containing the same number of atoms, molecules, ions, etc. as the number of atoms in a sample of pure 12C weighing exactly 12 g.

Given,

Molar mass of BF₃ = 67.81 g/mol

Mass = 2g

Moles = mass / molar mass

= 2 / 67.81

= 0.029 moles

1 mole = 6.023 × 10²³

0.029 moles = 6.023 × 10²³ × 0.029

= 1.776 × 10²² molecules

Thus, the ideal selection is option A.

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Considering the Dalton's partial pressure, the correct answer is option a.: the total pressure of the mixture is 1.86 atm.

The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{1} +P_{2} +...+P_{n}[/tex]

where n is the amount of gases present in the sample.

This relationship is due to the assumption that there are no attractive forces between the gases.

In this case, a mixture contains 220 mmHg of CO, 350 mmHg of Ne and 840 mmHg of He. The total pressure of the mixture can be calculated as:

[tex]P_{T} =P_{CO} +P_{Ne} +P_{He}[/tex]

[tex]P_{T} =220 mmHg +350 mmHg+840 mmHg[/tex]

Solving:

[tex]P_{T}[/tex]= 1410 mmHg

Being 760 mmHg=1 atm, then:

[tex]P_{T}=1410 mmHgx\frac{1 atm}{760 mmHg}[/tex]

Solving:

[tex]P_{T}[/tex]= 1.86 atm

Finally, the correct answer is option a.: the total pressure of the mixture is 1.86 atm.

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Answer:

African?

Explanation:

1 mL = 0.815 g

11.2 mL = X

X = 11.2 × 0.815

= 9.128 g

mole = 9.128/58

= 0.157 mole

1 mole = 6.02 × 10^23 atoms

0.157 mol = x

X = 0.157/1 × 6.02 × 10^23

= 9.451 × 10^22 atoms of C

please to recheck answers to ensure they are correct

I really hope this helps

Answer:

your question is not very clear but I think the answer is either

Primary (non-rechargeable)

Secondary (rechargeable) or

Lithium-ion battery.

Rechargeable li-ion button cell.

Answer:

A compound is something like atoms coming together as a team, and a mixture is 2 or more substances mixing together.

Explanation:

An experiment that would show that intramolecular forces are stronger than intermolecular forces will be heating a block of ice in a sealed container then allowing it to change to steam.

Intramolecular forces are the forces of attraction that hold atoms together within a molecule. Intramolecular forces require a high amount of energy to splits atoms or molecules in a chemical bonding.

Intermolecular forces are weaker forces of attraction that occur between molecules. They require lesser energy to splits molecules compared to intramolecular forces.

An experiment that would show that intramolecular forces are stronger than intermolecular forces will be heating a block of ice in a sealed container then allowing it to change to steam.

In the process, the energy required to change the state from ice to steam water is more than intermolecular forces.

Thus, we can conclude that this experiment shows that the intramolecular forces are stronger than the intermolecular forces.

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Answer:

Explanation:

7A 0.2

7B cork

7C  Yes because the lighter it is the more likely it will float

7D  Density is one of the fundamental scientific principles of life. It can describe any everyday object. Despite its significance, students often struggle to understand what it really is. Density is a measurement of how much space or volume is packed in an object or substance.

8   property means a characteristic or trait that you can use to describe matter by observation, measurement, or combination.

solid.................

Answer:

b solid

Explanation:

i know for a fact

The number of moles of the solute in the solution is the product of its volume and molarity. The number of moles of copper sulphate in 0.500 L of 2.30 M solution is 1.15 moles.

Molarity of a solution is the common term used to represent the concentration of a solution. It is the ratio of its number of moles of solute to the volume of solution in liters.

Molarity = no.of moles/volume in L.

Molarity is a temperature dependant quantity.

The given solution has a volume of 0.500 L.

molarity of copper sulphate solution = 2.30 M

Thus, number of moles of copper sulphate solute dissolved in 0.50 L of water is calculated by multiplying the volume with molarity.

No. of. moles of copper sulphate = molarity × volume

= 0.500 L × 2.30 M = 1.15 moles.

Therefore, there will be 1.15 moles of copper sulphate in the solution.

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Answer:

265hs+24.464536b+16o

Explanation:

265hs+16o+9b(2.718282)

=265hs+16o+24.464536b

=265hs+24.464536b+16o

Answer:

273.15 Kelvins

Explanation:

Answer:

The Sigma (σ) Bond

S-S Overlapping. In this kind of overlapping, one 's' orbital from each participating atom undergoes head-on overlapping along the internuclear axis. ...

S-P Overlapping. ...

P-P overlapping.

There are 2 electrons in the overlapping region.

Chlorine is the second member of the halogen group which are form of family of elements that resemble one another very closely.

The electronic configuration of chlorine shows the arrangement of chlorine electrons within it's atom.

At the outer most shell of the atom is seven electrons, therefore requires only one electron each to attain the octet arrangement.

The overlapping of the orbitals indicates the chemical bond formed by sharing of electrons between atoms called covalent bonding.

To complete it's outer most shell, it will need to share electron with another chlorine atom.

Therefore, there are 2 electrons in the overlapping region.

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Answer:

Water will generally require more energy for a phase change compared to a similar substance without hydrogen bonds.

Explanation:

Answer:

The basis for incomplete combustion is that instead of carbon dioxide being produced alongside water, carbon monoxide and carbon is produced instead, the carbon being released as soot. That handily sets the products up for the equation.

And combustion is simply a reaction between a fuel, in this case, methanol and oxygen.

The chemical formula for methanol is CH3OH. Simply write the reactants and products as a chemical equation and balance it, and you have the equation.

Explanation:

Answer:

Thermosphere

Explanation:

More specifically the ionosphere, since the ionosphere is the lower part of the thermosphere.

Hope this helps!

Easy!!

2+17=19

#hope that helps

Answer:

To find the answer you may

2+17=19

Explanation:

so that is the answer I'm sorry,to not give all the solutions

Answer: B. strontium

Explanation: This is due to electrons being further away from the nucleus in strontium.

Answer:

The primary producer uses some of that energy. Because we lose energy each time we move up a trophic level, we have more producers than consumers, more herbivores than carnivores, more primary consumers than secondary consumers. See this Socratic answer for more detail.

Explanation:

Answer:

Producers produce food energy for themselves and all the other levels

Explanation:

Answer: This would be C.) 70%

Explanation:

Answer:

It depends on their melting and/or their boiling points, because the heat provides the particles with kinetic energy to break the electrosatic bonds in the substances, which can differ in strength

Explanation:

Answer:

Remember the black and red dots represented in the below animation are not molecules. They are just markers enabling us to visualize the local displacement of air particles and so, the rise and fall of pressure within the wave medium.

The air is made up of many tiny particles. When sound is created, the air particles vibrate and collide with each other, causing the vibrations to pass between air particles. The vibrating particles pass the sound through to a person's ear and vibrate the ear drum. Light travels much faster than sound through air.

Explanation:

Answer:

1)  a) 2 C2H2 +  3O2 -->  2CO2 +  2H2O

b) Combustion Reaction

c) Bonds will be broken on the reactant side which will require energy.

d) It agrees with the law of conservation of mass because there are the same amount of molecules of each element on both sides of the equation, meaning mass was not created nor destroyed.

2) a) 2Na + Cl2 --> 2NaCl

        Synthesis

   b) 2Fe + O2 --> 2FeO

        Synthesis

Hope this helps!

Explanation:

To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation is

2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

a) 2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O is the balanced equation

b)Reaction is a Combustion Reaction

c) energy is required for the breaking of bond.

d) It agrees with the law of conservation of mass as the number  of atoms of each element on reactant and product side is same.

Therefore, the balanced equation is

2 C[tex]_2[/tex]H[tex]_2[/tex]+  3O[tex]_2[/tex] [tex]\rightarrow[/tex] 2CO[tex]_2[/tex]+  2H[tex]_2[/tex]O

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bcz the defination of matter is that

anything which occupy space

Hence , option a is correct

Answer:

4.002602

Explanation:

Seems Am Converting Between Grams Helium And Mole.