HIGH SCHOOL CHEMISTRY 25 PTS
Consider the following intermediate chemical equations.

3 equations. 1: upper C solid plus upper o subscript 2 gas right arrow upper C upper O subscript 2 gas Delta H 1 equals negative 393.5 kilojoules. 2: 2 upper C upper O gas plus upper O subscript 2 gas right arrow 2 upper C upper O subscript 2 gas Delta H 2 equals negative 566.0 kilojoules. 3: 2 upper H subscript 2 upper o gas right arrow 2 upper H subscript 2 gas plus upper O subscript 2 gas delta H 3 equals 483.6 kilojoules.

The overall chemical equation is Upper C (s) plus upper H subscript 2 upper O (g) right arrow upper C upper o (g) plus upper H subscript 2 (g).. To calculate the final enthalpy of the overall chemical equation, which step must occur?

~Reverse the first equation, and change the sign of the enthalpy. Then, add.
~Reverse the second equation, and change the sign of the enthalpy. Then, add.
~Multiply the first equation by three, and triple the enthalpy. Then, add.
~Divide the third equation by two, and double the enthalpy. Then, add.

1. Eukaryotes and Prokaryotes: I have a cell membrane (plasma membrane)

2. Eukaryotes: I have nucleus

3. Prokaryotes: Bacteria are an example of me

4. Eukaryotes: Fungi are an example of me.

5. Eukaryotes: Animals are an example of me.

6. Eukaryotes: I contain ribosomes.

7. Eukaryotes: I contain membrane-bound organelles.

8. Eukaryotes and Prokaryotes: I contain cytoplasm.

9. Eukaryotic cell: Your body cells are made of this type of cell.

10. Eukaryotes: Protists are an example of me.

11. Eukaryotes: Plants are an example of me.

12. Eukaryotes and Prokaryotes: I contain genetic material such as DNA.

Prokaryotes are organisms that are composed of cells that do not have a cell nucleus or any membrane-encased organelles.

Eukaryotes are organisms that are composed of cells that have a cell nucleus or any membrane-encased organelles.

An example of a prokaryote is bacteria. Fungi are an example of a eukaryote.

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Answer:

there u go

Explanation:

The one which helps to  establish the concentration gradient necessary for this process to occur is the Na⁺/K⁺ pump.

During neuronal signaling, a change in the membrane potential will cause the  sodium channels to open and let the Na⁺ ions diffuse down the concentration gradient into the cell. The sodium - potassium pump is an enzyme. The sodium - potassium pump helps to maintain the osmotic equilibrium and the potential in the cells.

Thus, the Na⁺/K⁺ pump helps to  establish the concentration gradient necessary for this process to occur.

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Answer:

The answer is "\(7.90 \ g\)".

Explanation:

Please finds the complete question in the attached file.

\(Volume = 10.0 \ mL \\\\Density =0.79 g\ cm^3\)

\(\text{Density}=\frac{Mass}{Volume}\)

\(Mass = Density \times Volume\)

         \(=(0.790 g\ cm^3) \times 10.0 \ mL\\\\=7.90 \ g\)

The mass of acetone to be weighed is \(7.90 \ g\)

Answer:

Desert

Explanation:

The adaptation shown by the given plants and animals shows that they will adapted to the desert biome.

It is so because, due to high temperature of desert some desert animals like camel have the storage of fat in humps or tails; some animals have large ears such as Jackrabbits, it helps to release body heat and adapt in high temperature; plants have thick water holding tissues to reduce water loss in heat and waxy coating that keeps  the plants cooler and reduce moisture loss.

Hence, the correct answer is "Desert".

Answer:

D

Explanation:

letters are in ascending order

Answer:

#4 is the correct answer

Explanation:

For #1, Cobalt has an ionic charge of +2

Chloride has a charge of -1, and Zinc has an ionic charge of +2. Therefore, Au has a charge of +1

Answer:

The main energy levels are the shells where the electron resides in a location that's relative to the atom's nucleus.

Explanation:

In electronic configuration in chemistry, the main energy levels are the shells where the electron resides in a location that's relative to the atom's nucleus. Such an energy level is usually denoted by the principal quantum number n. So n can be 1,2,3,4...e.t.c

Answer:

123.1L

Explanation:

Given parameters:

Molarity of Cu(NO₃)₂  = 0.650M

Mass of  Cu(NO₃)₂ = 15g

Unknown:

Volume of  Cu(NO₃)₂ = ?

Solution:

To solve this problem, we have to first find the number of moles of the given mass;

  Number of moles of Cu(NO₃)₂  = \(\frac{mass}{molar mass}\)

   Molar mass of Cu(NO₃)₂  = 63.5 + 2 (14 + 3(16)) = 187.5g/mol

 Number of moles of Cu(NO₃)₂  = \(\frac{15}{187.5}\)  = 0.08 mol

Molarity is given as;

  Molarity  = \(\frac{number of moles }{volume}\)  

         Volume  = \(\frac{number of moles }{molarity }\)  

  Insert the parameters and solve;

        Volume  = \(\frac{0.08}{0.65}\)  = 0.12L

Now mL;

         1L  = 1000mL

        0.12L will give 1000 x 0.12  = 123.1L

Answer:

To determine the identity of metal X, we need to compare the standard reduction potentials of the possible metals with the standard reduction potential of the Mg half-reaction.

From Table 18.1, we can find the standard reduction potentials for each of the metals listed:

Pb: -0.13 V

Zn: -0.76 V

Ni: -0.25 V

Fe: -0.44 V

Mn: -1.18 V

The reduction half-reaction for the Mg electrode is:

Mg2+ + 2e- → Mg E° = -2.37 V

The overall reaction for the galvanic cell is:

Mg(s) + X2+(aq) → Mg2+(aq) + X(s)

The standard cell potential is given by:

E°cell = E°(cathode) - E°(anode)

where the cathode is the reduction half-reaction and the anode is the oxidation half-reaction.

Substituting the given values, we get:

1.61 V = E°(X2+/X) - (-2.37 V)

Simplifying, we get:

E°(X2+/X) = 1.61 V + 2.37 V = 3.98 V

Comparing E°(X2+/X) with the standard reduction potentials in Table 18.1, we see that only zinc (Zn) has a reduction potential that is more negative than 3.98 V. Therefore, the metal X is zinc (Zn).

Therefore, the answer is (b) Zn.

2 moles of ZnO are produced if 1 mole of Zn and 2 moles of \(O_2\) is required.

A mole is defined as 6.02214076 × \(10^{23}\) of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

Balanced equation:

\(2 Zn + O_2\) → \(2 ZnO\)

For 2 moles of Zinc, we need 1 mol of Oxygen to produce 2 moles of Zinc oxide

For 1 mole Zn, we need 2 mol \(O_2\) to produce 2 moles ZnO only.

Hence, 2 moles ZnO is produced.

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The volume units that are greater than one liter are kiloliter and megaliter. Kiloliter is equal to 1,000 liters, and megaliter is equal to 1,000,000 liters.

The other volume units listed are smaller than one liter. Milliliter is equal to one-thousandth of a liter, centiliter is equal to one-hundredth of a liter, deciliter is equal to one-tenth of a liter, and nanoliter is equal to one-billionth of a liter.

Knowing the conversions between these volume units is essential in science and everyday life, as they are used to measure the volumes of liquids and gases in different contexts.

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The final temperature of the copper would be 30.26°C if it absorbed 150 J of heat.

To solve this problem, we can use the formula:

q = m * C * deltaT

where q is the heat absorbed by the copper, m is the mass of the copper, C is the heat capacity of copper, and deltaT is the change in temperature.

Rearranging the formula, we get:

deltaT = q / (m * C)

Substituting the given values, we get:

deltaT = 150 J / (75 g * 0.38 J/g°C) = 5.26 °C

Therefore, the final temperature of the copper will be:

25.0°C + 5.26°C = 30.26 °C

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The mass percentage is an important method which is used to calculate the concentration of a solution. The amount of water needed to add in order to make 17.85 % NaCl solution is 230.1 g.

The mass percentage of a component in a solution is defined as the mass in grams of that component present per 100 g of the solution. The term mass percentage is denoted as w/w. It is used to calculate the concentration of a binary solution.

Mass percentage = Mass of the component in the solution / Total mass of solution × 100

17.85 = 50.0 / 50.0 + x × 100

0.1785 (50.0 + x) = 50.0

8.925 + 0.1785 x = 50.0

0.1785 x = 41.075

x = 230.1 g

Thus the amount of water added to make the solution is 230.1 g.

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Answer:

neon sulfur iodine xenon

Answer:

1. The core electrons are 10

2. The valence electrons are 8

Explaination:

Core electrons are electrons located in  the inner shells of and atom.

Valence electrons are electrons located on the outermost shell of an atom

From the question given above, we obtained:

Ar (18) => [Ne] 3s²3p⁶

Recall

Ne (10) => 1s² 2s²2p⁶

Therefore,

Ar (18) => [1s² 2s²2p⁶] 3s²3p⁶

From the above illustration,

Inner shell (core shell) => 1s² 2s²2p⁶

Outermost shell (valence shell) => 3s²3p⁶

1. Determination of the core electrons

Inner shell (core shell) => 1s² 2s²2p⁶

Core electrons = 2 + 2 + 6

Core electrons = 10

2. Determination of the valence electrons

Outermost shell (valence shell) => 3s²3p⁶

Valence electron = 2 + 6

Valence electron = 8

Answer:

10 core electrons

8 valence electrons

Explanation:

Cr2Na2O7

Sodium Dichromate

Answer:

The answers to your questions are given below

Explanation:

F. Determination of the missing part of the equation.

_ I₂ + _Na₂S₂O₃ —> _ NaI + _ Na₂S₄O₆

The above equation can be balance as illustrated below:

I₂ + Na₂S₂O₃ —> NaI + Na₂S₄O₆

There are 2 atoms of I on the left side and 1 on the right side. It can be balance by writing 2 before NaI as shown below:

I₂ + Na₂S₂O₃ —> 2NaI + Na₂S₄O₆

There are 2 atoms of Na on the left side and a total of 4 atoms on the right side. It can be balance by writing 2 before Na₂S₂O₃ as shown below:

I₂ + 2Na₂S₂O₃ —> 2NaI + Na₂S₄O₆

Now the equation is balanced.

The coefficients are: 1, 2, 2, 1

Elements >>> Reactant >>> Product

Sodium >>>>> 4 >>>>>>>>> 4

Sulphur >>>>> 4 >>>>>>>>> 4

Oxygen >>>>> 6 >>>>>>>>> 6

Iodine >>>>>> 2 >>>>>>>>>> 2

G. Determination of the missing part of the equation.

__ Mg + __P₄ —> __Mg₃P₂

The above equation can be balance as illustrated below:

Mg + P₄ —> Mg₃P₂

There are 2 atoms of P on the right side and 4 atoms on the left side. It can be balance by writing 2 before Mg₃P₂ as shown below:

Mg + P₄ —> 2Mg₃P₂

There are 6 atoms of Mg on the right side and 1 atom on the left side. It can be balance by writing 6 before Mg as shown below:

6Mg + P₄ —> 2Mg₃P₂

Now the equation is balanced.

The coefficients are: 6, 1, 2

Elements >>>> Reactant >>> Product

Magnesium >> 6 >>>>>>>>> 6

Phosphorus >> 4 >>>>>>>>> 4

Explanation:

If there is a solid as a reactant, the surface of the solid will impact how fast the reaction goes. This happens because the 2 types of molecules can only bump into each other at the solid interface, which means on the surface of the solid. So, the larger the surface of the solid reactant, the faster the reaction will be.

Answer: D. On the surface of the solid.

Here are 3 alkali metals with physical and chemical similarity.

What is alkali metals?

alkali metals are come from the fact that when these metals or their oxides dissolved in water.a basic solution results.

Three alkali metals -

1- hydrogen(H)

2-lithium(Li)

3-potassium(K)

Physical and chemical similarity of hydrogen -

-it is colourless and tasteless in nature.

-it is a combustible gas but not a supporter of combustion.

Physical and chemical similarity of lithium -

-it have a melting point of 180.54

-it is the lightest of all metals,with a density approximately half that of water.

Physical and chemical similarity of pottasium -

- this metal is soft and white with a silver lustre.

-it imparts a lavender colour to a flame, and it's vapour is green.

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Answer:

25.88 g of F₂.

Explanation:

From the question given above, the following data were obtained:

Number of molecules of F₂ = 4.10×10²³ molecules

Mass of F₂ =?

From Avogadro's hypothesis,

1 mole of F₂ = 6.02×10²³ molecules

Next, we shall determine the mass of 1 mole of F₂. This can be obtained as follow:

1 mole of F₂ = 2 × 19 = 38 g

Thus,

38 g of F₂ = 6.02×10²³ molecules

Finally, we shall determine the mass of 4.10×10²³ molecules of F₂. This can be obtained as follow:

6.02×10²³ molecules = 38 g of F₂

Therefore,

4.10×10²³ molecules = 4.10×10²³ × 38 / 6.02×10²³

4.10×10²³ molecules = 25.88 g

Thus, 25.88 g of F₂ contains 4.10×10²³ molecules.

Answer:

68

Explanation:

Answer: 380 J. Please mark

Explanation:

The activity that we would have after 15 minutes would be  0.625 pCi.

The half-life, when referring to radioactive decay, is the amount of time needed for half of the radioactive isotopes in a sample to decay. Because they are unstable, radioactive isotopes spontaneously decay into other isotopes or elements. Each radioactive isotope has a distinctive attribute called a half-life that doesn't change over time.

We know that;

N/No = (1/2)^t/t1/2

N =No(1/2)^t/t1/2

N = 5(1/2)^15/5

N = 0.625 pCi

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Chemical property:

Physical property:

Answer:

8.42 moles (3 sig. figs.)

Explanation:

Given 5.07 x 10²⁴ atoms of antimony (Sb) => ? moles Sb

1 mole of any substance contains 6.02 x 10²³ particles ( atoms or molecules)

∴ Think in terms of 'how many 6.02 x 10²³'s are in 5.07 x 10²⁴ atoms Sb?

That is => moles Sb = 5.07 x 10²⁴ atoms Sb / 6.02 x 10²³ atoms Sb/mole Sb

= 8.42192691 moles Sb (calculator answer) ≅ 8.42 moles (3 sig. figs.)