what was johann dobereiner contribution to the periodic table

Answer:

1 mol contains 6.022*10^23 molecules 0.36 moles contain 0.36 * 6.022*10^23 = 2.2 *10^23 molecules

Explanation:

Answer:

D

Explanation:

The nuclear effective charge decreases as the energy of repulsion between the atoms increases between one another. The farther away an atom is from the nucleus, the more loosely that is attracted to that nucleus.

Taking into account the bond energy, the O=O bond is the strongest and the O–H bond is the weakest.

The bond energy is the average total energy that would be released by the formation of a mole of chemical bonds, from their constituent fragments (all in the gaseous state).

In other words, the normal or standard bond enthalpy is defined as the change in enthalpy or heat released, under standard conditions of 1 atmosphere and 25ºC, that accompanies the reaction of formation of one mole of bonds from the isolated atoms in gaseous state.

The higher the bond energy, the stronger and more stable the bond will be.

So, taking into account all the previous, the O=O bond is the strongest and the O–H bond is the weakest.

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Answer:

it is a nice question....my mind tells me that the first is it use me as a good vibes and can use to anything the second i will do my best too absorbe it.

Explanation:

Hope this help...

Answer:

an indirect cooling effect.

Explanation:

they play that role by reducing water vapor in the heat .

Answer:

Approximately [tex]41.2\; {\rm ^{\circ} C}[/tex].

Explanation:

Let [tex]t\; {\rm ^{\circ} C}[/tex] be the final temperature of the water and the iron.

Temperature of the water would be increase by [tex](t - 38.00)\; {\rm ^{\circ} C}[/tex].

Temperature of the iron would be reduced by [tex](100.0 - t)\; {\rm ^{\circ} C}[/tex].

Let [tex]c[/tex] denote the specific heat of each material. Let [tex]m[/tex] denote the mass of the material. For a temperature change of [tex]\Delta t[/tex], the energy change involved would be:

[tex]Q = c\, m \, \Delta t[/tex].

The energy that the water need to absorb would be:

[tex]\begin{aligned}& Q(\text{water, absorbed}) \\ =\; & c(\text{water}) \, m(\text{water})\, \Delta t (\text{water}) \\ =\; & 4.181\; {\rm J \cdot g^{-1} \cdot K^{-1}} \times 50\; {\rm g} \times (t - 38.00)\; {\rm ^{\circ} C} \\ =\; & (209.05\, t - 7943.9)\; {\rm J} \end{aligned}[/tex].

The energy that the iron would need to release would be:

[tex]\begin{aligned}& Q(\text{iron, released}) \\ =\; & c(\text{iron}) \, m(\text{iron})\, \Delta t (\text{iron}) \\ =\; & 0.45\; {\rm J \cdot g^{-1} \cdot K^{-1}} \times 25.0\; {\rm g} \times (100.0 - t)\; {\rm ^{\circ} C} \\ =\; & (1125 - 11.25 \, t)\; {\rm J} \end{aligned}[/tex].

Since this calorimeter is insulated, the energy that the iron had released would be equal to the energy that the water had absorbed:

[tex]Q(\text{water, absorbed}) = Q(\text{iron, released})[/tex].

[tex]209.05\, t - 7943.9 = 1125 - 11.25\, t[/tex].

[tex]t \approx 41.2[/tex].

Thus, the final temperature of the water and the iron would be approximately [tex]41.2\; {\rm ^{\circ} C}[/tex].

Answer:

15.63%

Explanation:

The formula of error percentage is:

([experimental value-real value]/real value)100%

You divide the subtraction of the absolute value of experimental value (the one you got during a experiment) and the one that's "proven" to be right by again, the proven value. You got a decimal and all you have to do is multiply it by 100%

Answer:

on acellus the answer is 16%

I hate acellus

Explanation:

Explanation:

1. b is correct because 10^-2 is 1/100. multiplying that by 1.862 is 0.01862

2. 6 feet 10 inches = 82 inches. multiplying 82 by 2.54 we get 208.28. there are only two sig figs so it's 210 cm, not 0.21 cm.

3. 25.2 x 39370 = 992000, which is 9.92 x 10^5.

Taking into account the room temperature and pressure, there are 0.4167 moles in 10 dm³ of sulfur dioxide gas.

RTP refers to Room Temperature and Pressure. Pressure is 1 atm and Temperature is 298K. In this case, one mole of any gas has a volume of 24 dm³ or 24,000 cm³. This volume is called the molar volume of a gas.

In other words, the molar volume (the amount of space occupied by one mole) of any gas is 24dm³ (1 mol of gas molecules occupies 24.0 dm³).

Therefore, the amount of volume occupied by any gas can be calculated by multiplying the number of moles of gas by 24dm³:

Volume = Moles of gas× 24 dm³

So, the number of moles can be calculated as:

Moles of gas= Volume÷ 24 dm³

In this case, you know that volume if sulfur dioxide gas is 10 dm³. So, replacing:

Moles of gas= 10 dm³ ÷ 24 dm³

Solving:

Moles of gas= 0.4167

Finally, there are 0.4167 moles in 10 dm³ of sulfur dioxide gas.

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Answer:

No, ionic compounds are crystals of infinite cations and anions bound together. There is no “molecule” of ionic compounds such as, for example, NaCl, because there are no single units of the compound.

Explanation:

Ionic compounds are not considered to be molecules because they do not consist of discrete, covalently bonded units like molecules.

In ionic compounds, the bonding occurs through the transfer of electrons from one atom to another, resulting in the formation of ions. These ions are held together by strong electrostatic attractions, known as ionic bonds.

Unlike molecules, which are formed by the sharing of electrons in covalent bonds, ionic compounds do not have individual units with fixed numbers of atoms. Instead, they exist as a three-dimensional lattice structure composed of alternating positive and negative ions. The ions are arranged in a repeating pattern throughout the crystal lattice.

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Answer:

[tex] \huge{3.783 \times {10}^{ - 19} \: J}[/tex]

Explanation:

The energy of the wave can be found by using the formula

where

E is the energy

f is the frequency

h is the Planck's constant which is

6.626 × 10-³⁴ Js

From the question we have

E = 6.626 × 10-³⁴ × 5.71 × 10¹³

We have the final answer as

[tex]3.783 \times {10}^{ - 19} \: J[/tex]

Hope this helps you

Considering the reaction stoichiometry and Avogadro's Number, the mass of barium chloride produced is 21.6 grams.

The balanced reaction is

2 HCl + Ba → BaCl₂ + H₂

Avogadro's Number is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

Then you can apply the following rule of three: if 6.023×10²³ molecules are contained in 1 mole of HCl, then 1.25×10²³ molecules are contained in how many moles of HCl?

amount of moles of HCl= (1.25×10²³ molecules × 1 mole)÷ 6.023×10²³ atoms

amount of moles of HCl= 0.2075 moles

Then, 0.2075 moles of HCl react.

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Then you can apply the following rule of three: if by stoichiometry 2 moles of HCl produce 1 mole of BaCl₂, 0.2075 moles of HCl will produce how many moles of BaCl₂?

[tex]amount of moles of BaCl_{2} =\frac{0.2075 moles of HCl x 1 mole of BaCl_{2} }{ 2moles of HCl}[/tex]

amount of moles of BaCl₂= 0.10375 moles

Being the molar mass of BaCl₂ 208.24 g/mole, then the mass of barium chloride produced is calculated as:

[tex]0.10375 molesx\frac{208.24 grams}{1 mole} =21.6 grams[/tex]

Finally, the mass of barium chloride produced is 21.6 grams.

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Explanation: In solids, particles are very closely packed in an orderly arrangement in a lattice and only vibrate in fixed positions. The forces of attraction between them are very strong. This allows them to overcome the forces of attraction that hold the other phases closer together

Answer:

3... uhm I'm not sure it could 2

Answer:

Explanation:

Answer:

Because they do not naturally react with other elements

Explanation:

Since noble gases do have a fulfilled valence shell, they do not react with other elements because they're already stable by the themselves.

Answer:

pipe

Explanation:

You receiving

Answer:

helium and hydrogen make up the first of these

the answer is period

Newton’s second law of motion is a dot product of mass and acceleration, if you remove the table from, under the book, gravity will act on the book and pull it downwards to the centre of the earth

Newton's Second law of motion states that "the acceleration of an object depends upon two variables – the net force acting on the object and the mass of the object."

In our case the mass of the book and the force of gravity

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Answer:

34 ATP

Explanation:

Taking into account the Newton's second law, the correct answer is option A. F = 9.68 N right

In first place, acceleration in a body occurs when a force acts on a body.

Newton's second law states that a force will change the speed of an object because the speed and/or direction will change. These changes in velocity are called acceleration.

So, Newton's second law defines the relationship between force and acceleration mathematically. This law says that the acceleration of an object is directly proportional to the sum of all the forces acting on it and inversely proportional to the mass of the object

Mathematically, Newton's second law is expressed as:

F= m×a

where:

In this case, you know:

Replacing in Newton's second law:

F= 2.2 kg× 4.4 m/s²

Solving:

F= 9.68 N

Finally, As the bowl of fruit accelerates to the right, the correct answer is option A. F = 9.68 N right

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To solve such this we must know the concept of double displacement reaction. Therefore, the correct option is option B that is kinetic energy of collisions of reactant particles.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

There are so many factors that affects the rate of reaction, among these, kinetic energy of collisions of reactant particles affect the rate of a chemical reaction. the rate of reaction is directly proportional to the rate of chemical reaction.

Therefore, the correct option is option B.

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The systematic Iupac name for the internal alkyne is : 4-octyne

When only one type of carboxylic acid is made the internal alkyne will be symmetric and the compounds can be 3-hexane or 4-octyne but given that one of the reactants is propyl iodide. Therefore

The Internal alkyne will have an Iupac name 4-octyne

Hence we can conclude that the systematic Iupac name for the internal alkyne is 4-octyne

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The cart with the greatest change in speed is the cart with a mass of 75 Kg

Acceleration is defined as the change in velocity of an object with time. Also, acceleration is related to the force and mass according to the following equation:

Acceleration (a) = Force (F) / mass (m)

To answer the question, we shall determine the acceleration of each cart.

a = F / m

a = 200 / 75

a = F / m

a = 200 / 125

a = F / m

a = 200 / 350

a = F / m

a = 200 / 450

From the above illustrations, we can see that the cart with a mass of 75 K has the greatest change in speed (i.e 2.67 m/s²)

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Answer:

D

Explanation:

F. 200-75=125

G. 20-125=75

H. 350-200=150

J. 450-200=250

250 is the biggest number so it has the biggest change

CH=benzene

Why?

benzene is represented by the empirical formula CH, which indicates that a typical sample of the compound contains one atom of carbon (C) to one atom of hydrogen (H).

----(Is this what you meant???)

Answer:

Coca-Cola or Pepsi

Explanation:

Im sure one of those

Answer:

option A it has equal numbers of electrons and protons

Explanation:

electrons are negatively charged and protons are positively charged, so if the numbers of each are equal, then the atom will be neutral.

Answer:

A. it has equal numbers of electrons and protons

Explanation:

The overall charge of every atoms is neutral because the number of electrons and protons is the same. Protons are positively charged while electrons are negatively charged and so they cancel out.