Neils Bohr published his model of the atomic structure in 1913. He introduced the theory of electrons traveling in orbits around the atom's nucleus, with electrons orbiting only in certain orbits called shells. Each shell can contain a fixed number of electrons.

According to this model of the atom, the chemical properties of an element are mainly determined by

A)
the number of electrons in the outer shells.


B)
the number of electrons in the inner shells.


C)
the total number of electrons in all shells.


D)
the difference between number of electrons and protons.
Elim

Answer:

True

Explanation:

as the ph of pure water is 7

(-)log(10^-7) = 7

The statement if the pH of pure water is 7.0, the hydroxide ion concentration in pure water is 1 × 10⁻⁷M is true.

Hydroxide ion concentration in the solution will be calculated by using the below equation as:

pOH = -log[OH⁻]

Relation between pH and pOH is :

pH + pOH = 14

Given that, pH = 7

So, pOH = 14 - 7 = 7

By using first equation, we have

7 = -log[OH⁻]

[OH⁻] = 10⁻⁷M

Hence, hydroxide ion concentration in pure water is 1×10⁻⁷M.

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Answer:

0.6 mol/L.s.

Explanation:

3O₂ → 2O₃,

the rate of the reaction = - 1/3d[O₂]/dt = 1/2d[O₃]/dt

where, d[O₂]/dt is the rate of change of O₂ concentation = - 0.9 mol/L.s.

d[O₃]/dt is the rate of change of O₃ concentration.

∴ d[O₃]/dt = - 2/3(d[O₂]/dt) = - 2/3(- 0.9 mol/L.s) = 0.6 mol/L.s.

Answer:

A. Yes, Amanda find the number of moles of NaCl correctly.

B. 0.73 M.

Explanation:

A. Did Amanda find the number of moles of NaCl correctly? If not, explain.

No. of moles (n) of NaCl = mass/molar mass.

mass of NaCl = 32.0 g, molar mass of NaCl = 58.45 g/mol.

∴ No. of moles (n) of NaCl = mass/molar mass = (32.0 g)/(58.45 g/mol) = (32.0 g NaCl)*(1 mol of NaCl)/(58.45 g NaCl) = 0.547 mol ≅ 0.55 mol.

B. What does Amanda need to do next to calculate the molarity of the NaCl solution? Show your work for full credit.

∴ M = (no. of moles of NaCl)/(volume of solution (L)) = (0.55 mol)/(0.75 L) = 0.73 M.

Answer: I believe the Answer is A

Answer:

a substance whose nuclei do not stay together

Explanation:

Answer:

Explanation:

That's almost the exact definition of an ecosystem.

Hello!

I think an ecosystem because they are a biological community of interacting organisms and their physical environment. And that’s what an ecosystem is and it relates to your question.

I hope I answered in time!

Good luck!

~ Destiny ^_^

Answer:

heat is relaesed

a decrease in temperature

less than the chemical energy

written as a reactant

Explanation:

Answer:

Answer is Below

Explanation:

For an exothermic reaction, heat is released. Which means that...

1. Heat is written as a product of the reaction.

2. A rise in temperature occurs.

3. Heat is released into the surroundings.

and 4. The chemical energy stored in the bonds of the products is less than that stored in the reactants.

This diagram also explains why this is the case, the chemical energy is lower as you see the products is lower on the graph as compared to the reactants.

They are gases at room temperature

Hope this helps:)

The smallest alkanes, which are those with one to four carbon atoms, are gases at room temperature due to their nonpolar nature and weak dispersion forces.

The physical state of the smallest alkanes at room temperature can be understood by analyzing their properties and boiling points. Alkanes are nonpolar molecules associated through weak dispersion forces. The boiling point of a substance is a rough measure of the energy needed to separate molecules from each other. In the case of the smallest alkanes, specifically those with one to four carbon atoms, they are gases at room temperature. Example alkanes that are gases at room temperature include methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). In contrast, the physical state changes as the number of carbons increases; alkanes become liquids and eventually solids as the carbon chain length and molecular weight increase.

The answer is excess reactant

Answer: option B, excess reactant

Explanation:

Since one the reactants is in excess(high amount) compared to other.

Example reaction of H2& Cl2 gives HCl.

If we take excess H2 compared to Cl2. Then we call H2 as excess Reactant.

Answer:

Explanation:

Boyle's law for gases states that, at constant temperature, the volume and pressure of a fixed amount of gas are inversely related.

Mathematically, that is:

Here, you have:

Then, you can solve for V₂:

Substitute and compute:

Answer:

0.40 L

Explanation:

Answer:

oxygen is produced at the anode and hydrogen gas is produced at the cathode

Explanation:

The statement true about electrolysis of water are;

Electrolysis is a process in which direct current is use to alter or change the chemical composition of a substance when the current is pass through it.

Therefore, The statement true about electrolysis of water are;

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Answer:

The weak nuclear force.

Explanation:

This force is active in radioactivity.

Answer:

4.549 kg.

Explanation:

where, P is the pressure of the gas in atm (P = 2 x 10⁴ kPa/101.325 = 197.4 atm).

V is the volume of the gas in L (V = 20.0 L).

n is the no. of moles of the gas in mol (n = ??? mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 23° C + 273 = 296 K).

∴ n = PV/RT = (197.4 atm)(20.0 L)/(0.0821 L.atm/mol.K)(296 K) = 162.5 mol.

mass of N₂ = (no. of moles of N₂)*(molar mass of N₂) = (162.5 mol)*(28.0 g/mol) = 4549 g = 4.549 kg.

A on nudity

Reason: ye

Answer:

[tex]\boxed{\text{0.60 L}}[/tex]

Explanation:

We can use Gay-Lussac's Law of Combining Volumes to solve this problem.

Gases at the same temperature and pressure react in the same ratios as their coefficients in the balanced equation.

1. Write the chemical equation.

Ratio: 2 L     1 L

           2H₂ + O₂ → 2H₂O

V/L:   1.2

2. Calculate the volume of O₂.

According to Gay-Lussac, 1 L of O₂ forms from 2 L of H₂.

Then, the conversion factor is (1 L O₂/2 L H₂).

[tex]\text{Volume of O}_{2} = \text{1.20 L H}_{2}\times \dfrac{\text{1 L O}_{2}}{\text{2 L H}_{2}} = \textbf{0.60 L O}_{2}\\\\\text{You need }\boxed{\textbf{0.60 L of O}_{2}}[/tex]

Answer:

Explanation:

The angular momentum quantum number, identified with the letter l (lowercase L),  number is the second quantum number.

This number identifies the shape of the orbital or kind of subshell.

The possible values of the angular momentum quantum number, l, are constrained by the value of the principal quantum number n: l can take values from 0 to n - 1.

So, you can use this guide:

Principal quantum   Angular momentum         Shape of the orbital

number, n                 quantum number, l

         1                                      0                             s

         2                                     0, 1                          s, p

         3                                     0, 1, 2                      s, p, d

Hence,

Answer:it speeds up the reaction

Explanation:

Answer:

a) 5

b) 4

c) 3

d) 3

e) 4

Explanation:

I use only one rule when the decimal is present, meaning you can see the decimal (as is the case with all of these).

When the decimal is Present, start counting sig figs from the Pacific (left) side of the number beginning with the first non-zero digit and count all the way to the end.

So, for example, in "a", the first non-zero digit starting from the left is 1, then continue counting all the way to the right side.

For "c",  the first non-zero digit is the left most 4 (skip the first 4 zeros), then count all the way to the right side.

A potassium atom loses one electron to form a potassium ion with a +1 charge, while a sulfur atom gains two electrons to form a sulfide ion with a -2 charge.

Metals and nonmetals can react with each other to form ions through the transfer of electrons. When a potassium atom reacts, it loses one electron and forms a potassium ion with a +1 charge (K+). Potassium is an alkali metal and it typically loses one electron to achieve a noble gas electron configuration.

On the other hand, a sulfur atom typically gains two electrons to form a sulfide ion with a -2 charge (S2-). As a nonmetal, sulfur gains electrons to achieve an octet, resembling the electron configuration of a noble gas.

Answer:

The catalyst is unchanged.

Explanation:

Hope my answer has helped you!

Answer:

D. Temperature

Explanation:

Temperature is not energy, let's just make that point first. So how can it be the average kinetic energy then?

Well, the short answer is, it is just a number. Temperature is a number that represents the average kinetic energy. It is important to note that temperature only relates to kinetic energy in substances.

This is what makes it different from heat. Heat considers all forms of energy in the substance.

Answer:

TEMPERATUE

Explanation:

Answer: metal and carbonate

Explanation:

According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions [tex](OH^-)[/tex] when dissolved in water and an acid is defined as a substance which donates hydrogen ions [tex](H^+)[/tex] in water.

An acid is represented as :

[tex]HX\rightarrow H^++X^-[/tex]

1. When metal is treated with an acid such as [tex]HCl[/tex], if the metal is more reactive than hydrogen displaces hydrogen from its salt solution and thus produce zinc chloride and hydrogen gas.

[tex]M+xHCl(aq)\rightarrow MCl_x(aq)+xH_2(g)[/tex]

2. When carbonates are treated with acid, double displacement takes place ad carbon dioxide is released as a gas.

[tex]MCO_3(aq)+xHCl(aq)\rightarrow MCl_x(aq)+xH_2O(l)+CO_2(g)[/tex]

Answer:

for those in a hurry, its C

Explanation:

on edge. Metal and carbonates

The molarity of a solution is typically directly related to its absorption. This relationship is expressed through the Beer-Lambert law, and can be written as A=ecl. This is usually used in spectroscopy and research.

Hope this helps!

Answer:

(Percent yield × theoretical yield) ÷ 100.

Explanation:

∵ percent yield of the reaction = [(actual yield)/(theoretical yield)] x 100.

∴ actual yield = [(percent yield of the reaction) x (theoretical yield)]/100.

So the right choice is: (Percent yield × theoretical yield) ÷ 100 .

Answer : The correct option is, [tex]\frac{(\text{Percent yield}\times \text{Theoretical yield})}{100}[/tex]

Explanation :

The formula used for the percent yield will be :

[tex]\text{Percent yield}=\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100[/tex]

or,

[tex]\text{Actual yield}=\frac{(\text{Percent yield}\times \text{Theoretical yield})}{100}[/tex]

For example : If we are given that the percentage yield of a sample is 94.92% and the theoretical yield is 83.475 g. Now calculate the actual yield of the sample.

By using formula we get the value of actual yield.

[tex]\text{Actual yield}=\frac{(94.92\times 83.475)}{100}=79.23g[/tex]

Thus, the actual yield is, 79.23 g.

Hence, the formula used to calculate the actual yield can be, [tex]\frac{(\text{Percent yield}\times \text{Theoretical yield})}{100}[/tex]

Answer:

Explanation:

The boiling point of a pure solven increases when a solute is added and a solution is formed.

The increase of the boiling point of a solvent, when a non-volatile solute is added, is a colligative property, meaning that it depends of the number particles of solute dissolved.

The equation that rules the increase of the boiling point is:

Where:

Then, since Kb is constant (because it is the same solvent for all the solutions), you must look at the product m × i.

For ionic solutes you assume 100% ionization, which drives to:

Solution                  Ionization           i        m         m × i

A) 2.0 BaCl₂             Ba⁺² + 2Cl⁻       3      2.0        6.0     ↔ highest

B) 2.0 NaNO₃          Na⁺ + NO₃⁻       2      2.0        4.0      ↔ second

C) 1.0 C₆H₁₂O₆          none                1       1.0         1.0      ↔ lowest (fourth)

D) 1.0 K₂SO₃             2K⁺ + SO₃²⁻      3      1.0         3.0     ↔ third

Then, 6.0 > 4.0 > 3.0 > 1.0 and the final list of the solutions arranged in order from highest boiling point to lowest boiling point is:

Answer:

The order should be ABDC.

Explanation:

To calculate the amount of heat energy added to the water, multiply the mass of water by the specific heat of water and the change in temperature.

To calculate the amount of heat energy added to the water, we can use the equation:

q = m * c * ΔT

Where q is the heat energy, m is the mass of the water (2 grams), c is the specific heat of water (4.184 J/g °C), and ΔT is the change in temperature (final temperature minus initial temperature).

Substituting the values into the equation, we get:

q = 2g * 4.184 J/g°C * (50°C - 40°C)

q = 2g * 4.184 J/g°C * 10°C

q = 83.68 J

Therefore, 83.68 Joules of heat energy is added to 2 grams of water.

The answer is d ionic

The law is Boyel's law.

One of the primary laws of material science that impacts the submerged jumping condition for scuba jumpers is Boyle's law.  

The law states that as weight changes, the volume of gases in a jumper's body pits and adaptable gear changes as well. Where the water weight builds, 'air spaces' reduces in size, yet as water weight diminishes, the 'air spaces' increments in size. Where the two changes are in direct extent to the weight increment or lessening, the temperature is held consistent.  

Answer:

The new volume of the balloon is 600cm³

Explanation:

Given parameters:

Initial Volume, which is V₁ = 200cm³

Initial temperature, T₁ = 60°C

Final temperature T₂ = 180°C

Final Volume V₂ =?

To solve this kind of problem, we apply one of the gas laws that shows the relationship between volume and temperature.

This law is the Charles law, it states that " the volume of a fixed mass of a gas is directly proportional to its absolute temperature if pressure is constant".

It is simply expressed as:

V₁/T₁ = V₂/T₂

Since our unknown is V₂, we make it the subject of the expression given above:

V₂ = V₁T₂/T₁

Now input the corresponding values and solve:

V₂ = 200 x 180 / 60

V₂ = 36000/60

V₂ = 600cm³

The new volume of the balloon is 600cm³

Answer:

404 J

Explanation:

The amount of heat given off by the magnesium sample is given by:

[tex]Q=mC_s \Delta T[/tex]

where

m = 20.0 g is the mass of the sample

[tex]C_s = 1.01 J/gC[/tex] is the specific heat capacity of the magnesium

[tex]\Delta T=50.0 C-70.0 C=-20.0^{\circ}[/tex] is the change in temperature

Substituting into the equation, we find

[tex]Q=(20.0 g)(1.01 J/gC)(-20.0^{\circ})=-404 J[/tex]

and the negative sign means the heat is given off by the sample.

Using the formula for heat exchange (q = mcΔT), we find that a 20.0 gram sample of magnesium releases 404 Joules of heat when cooling from 70.0°C to 50.0°C

The student's question involves the physics concept of specific heat. Specific heat is the heat required to change the temperature of 1 gram of a substance by 1 degree Celsius, it's an intensive property. To calculate the amount of heat given off you can use this formula: q = mcΔT, where:

For the given problem, the mass (m) of magnesium is 20.0 grams, its specific heat (c) is 1.01 J/g°C and the change in temperature (ΔT) is 70.0°C - 50.0°C = 20.0°C. So,

q = mcΔT

= (20.0 g) * (1.01 J/g°C) * (20.0°C)

= 404 J

Therefore, 404 Joules of heat is released when the 20.0 gram sample of magnesium cools from 70.0°C to 50.0°C.

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Answer:

D. Earth's internal heat engine and the water cycle

Explanation:

The rock cycle is driven by the earth's internal heat engine and the water cycle.

The internal heat engine furnishes the earth with the required energy. The energy is used to melt rocks within the earth crust and to initiate convective cells in the mantle. This causes rocks to melt and plates to move. As this occurs, igneous and metamorphic processes takes place.

The water cycle is greatly responsible for the weathering and erosion of rocks. Through these processes of denudation, sediments are formed and deposited within basins on the crust. The action of runing water and glacier plays a very significant role in forming sedimentary rocks.

The interplay between the internal heat Engine and water cycle moves crustal materials to deeper levels of the earth and also deep seated materials to the crust.

The two forces that primarily drive the rock cycle are Earth's internal heat engine and the water cycle. Therefore, option D is correct.

The Earth's internal heat engine, which includes processes like volcanic activity, tectonic plate movements, and mountain building plays a crucial role in the rock cycle.

These processes generate heat and pressure that lead to the formation of new rocks through processes such as solidification, crystallization, and metamorphism.

The water cycle, driven by solar energy, also plays a role as it contributes to weathering and erosion by causing precipitation, runoff, and the movement of water through different stages.

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