What information guided Mendeleev as he placed elements in his periodic table

I believe your answer might be

D) About 550 million more people speak Mandarin than speak Hindi.

Knowing the mass and radius of the Earth and the distance of the Earth from the sun, we can calculate the mass of the sun (right), again by using the law of universal gravitation. The gravitational attraction between the Earth and the sun is G times the sun's mass times the Earth's mass, divided by the distance between the Earth and the sun squared. This attraction must be equal to the centripetal force needed to keep the earth in its (almost circular) orbit around the sun. The centripetal force is the Earth's mass times the square of its speed divided by its distance from the sun. By astronomically determining the distance to the sun, we can calculate the earth's speed around the sun and hence the sun's mass.

Astronomers determine the gravitational force between celestial objects by observing their motion and applying Kepler's law together with the Doppler effect. This allows the calculation of the masses involved and hence gravitational forces. These methods work for celestial bodies near or far.

Astronomers determine the gravitational force between two celestial objects indirectly by using observations and mathematical laws. For example, by observing the orbits of stars close to the galactic center and using Kepler's third law, we can estimate the mass of a black hole in a far-off galaxy. Similarly, by measuring the orbital speed of gas in the rotating accretion disk of distant galaxies, we can calculate the gravitational force exerted by the central object.

The Doppler effect is another important tool in this process, which is used to measure radial velocities of the orbiting material and thus derive the speed at which it moves around. This speed tells us about the central body's gravitational force. Gravitational effects between two bodies also allow the calculation of masses of astronomical objects.

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Hey There,

When one nucleus after another is split,

C) A chain reaction begins

Best Of Luck,

- I.A. -

Answer: A chain reaction begins

The electromagnetic spectrum encompasses all electromagnetic wave frequencies, including visible light, option C is correct. A television remote control does not use radio waves but instead uses infrared light, option D is correct. A material that lets some light pass through, creating a diffused effect, is termed translucent, option C is correct.

The entire range of electromagnetic wave frequencies is known as the electromagnetic spectrum. This spectrum includes all types of electromagnetic radiation, from radio waves and microwaves to infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. The electromagnetic spectrum is categorized by wavelength or frequency, with radio waves being at the low-frequency end and gamma rays at the high-frequency end, option C is correct,

Among the devices listed, the one that does not utilize radio waves is a television remote control. Instead, a television remote typically uses infrared light to communicate with the television. Radio waves are widely used in telecommunications, such as by cellular telephones, radar systems, and satellites to transmit and receive signals, option D is correct.

A material that allows only some light to pass through, neither completely transparent nor completely opaque, is described as translucent. Translucent materials may scatter light as it passes through, allowing light to pass but not detailed images, creating a softer, diffused effect. Examples of translucent materials include frosted glass and some plastics, option C is correct.

1.atoms

2.two

3. Elements are combined to make compounds

4.fewer

5. Larger  

6. Starch is made up of three Elements.

I’m not sure about the other two but I hope this helped!!

The substances and their chemical formulas are: water (H2O), hydrogen ion (H+), hydronium ion (H3O), and hydroxide ion (OH-)

1. H+ matches with the chemical formula H2O, which represents water.

2. H2O matches with the chemical formula H2O, which represents water.

3. H3O matches with the chemical formula H3O, which represents the hydronium ion.

4. OH- matches with the chemical formula OH-, which represents the hydroxide ion.

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98.857g Na

To find this, set up an equation as so:

4.3 mol Na = [tex]\frac{22.99g Na}{1 mol Na}[/tex]

Multiply everything on the top and divide that by everything on the bottom to get the final answer of 98.857g Na.

Hope this helps!

Answer: D relative humidity

Explanation: Just took the test.

Relative Humidity is the amount of water vapor in air, as a percentage of the maximum amount the air could hold at the same temperature. The other options refer to different concepts in weather science and chemistry.

The amount of water vapor in the air, compared to the maximum amount that can be held at a specific air temperature is called Relative Humidity. This term is a measure used in weather science to describe the percentage of moisture in the air in relation to the maximum amount the air could hold at the same temperature.

For example, if the Relative Humidity is 50%, it means that the air is carrying 50% of the total moisture it could hold at that particular temperature.

Other options like Dew Point, Precipitation, and Crystallization refer to different concepts. Dew Point is the temperature at which the air is saturated and water vapor begins to condense into dew. Precipitation is any form of water particles, liquid or solid, that fall from the atmosphere and reach the ground. Crystallization is a process in chemistry involving the formation of solid crystals from a homogeneous solution.

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Final answer:

The cell membrane regulates the movement of materials in and out of the cell through selective permeability and transport proteins.

Explanation:

The cell membrane is responsible for regulating the movement of materials in and out of the cell. It is selectively permeable, allowing some substances to pass through while blocking others. This selective permeability helps to maintain the internal environment of the cell and ensures the cell's survival.

Transport proteins in the cell membrane act as channels or pumps to facilitate the movement of specific molecules in and out of the cell. These proteins play a crucial role in maintaining the balance of salts, nutrients, and proteins within the cell.

An example of a transport protein is ion channels. Ion channels regulate the movement of ions such as sodium, potassium, calcium, and chloride across the cell membrane. These ions are essential for various cellular processes and maintaining membrane potential.

Answer:

t should include correct results and not include the falsified results

Explanation:

The balanced equation is

4Fe(s) +  3O2(g)  ---> 2Fe2O3(s)

here four moles of Fe will react with O2 to give 2 moles of Fe2O3

mass of Fe reacted = 33.4 grams

moles of Fe reacted = mass of Fe / atomic mass of Fe

moles of Fe reacted = 33.4 / 55.8 = 0.599 moles

moles of Fe2O3 formed = 0.5 X 0.599 = 0.2995 moles

so mass of Fe2O3 formed = moles X molar mass = 0.2995 X 159.69 = 47.83 g

To determine the amount of iron(III) oxide produced, we used stoichiometry to relate the given mass of iron to the mass of  Fe₂O₃ produced via the balanced equation, resulting in the formation of 47.76 grams of  Fe₂O₃.

The student asked how many grams of Fe₂O₃  are formed when 33.4 g of Fe reacts completely with oxygen. We'll solve this by using stoichiometry based on the balanced chemical equation for the reaction between iron and oxygen:

4 Fe + 3 O₂ arr 2 Fe₂O₃

Firstly, we need to find the number of moles of iron:

Number of moles of Fe = mass of Fe / molar mass of Fe = 33.4 g / 55.85 g/mol

Calculate moles of Fe₂O₃  using the mole ratio from the balanced equation. As per the equation, 4 moles of Fe produce 2 moles ofFe₂O₃ . Therefore, the number of moles of iron will be halved to find the moles of  Fe₂O₃.

Finally, convert the number of moles of Fe₂O₃  to grams using its molar mass (55.85 g/mol for Fe and 16.00 g/mol for O, resulting in 159.7 g/mol for Fe₂O₃ ).

Using the above steps, the specific calculations are:

33.4 g Fe / 55.85 g/mol Fe = 0.598 moles Fe

0.598 moles Fe arr 0.598 / 2 = 0.299 moles

0.299 moles Fe₂O₃  × 159.7 g/mol Fe₂O₃ = 47.76 g  (rounded to two decimal places)

This means that 47.76 grams of Fe₂O₃ are formed when 33.4 grams of Fe reacts with oxygen.

See , from the equation we can see that for forming two mole of H2O 2Mole of H2 has to react.

Mass of 2 Mole H2O is 18*2gm or 36gm.

So for forming 36 gm H2O 2×2 I.e. 4 gm H2 has to take part in reaction.

Therefore, to form 1 gm H2O 4÷36 gm of H2 has to take part.

So, for forming 47gm H2O (4÷36)×47 gm H2 has to take part

I.e. 5.22 gm of H2 has to take part

So, ans is 5.22 gm of hydrogen.

Hope it helps!!!

Answer: Mass of hydrogen gas that must react will be 5.22 grams.

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]   ....(1)

Given mass of water = 47 g

Molar mass of water = 18 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of }H_2O=\frac{47g}{18g/mol}=2.61mol[/tex]

For the given balanced chemical equation:

[tex]2H_2+O_2\rightarrow 2H_2O[/tex]

By Stoichiometry of the reaction:

2 moles of water are formed from 2 moles of hydrogen gas.

So, 2.61 moles of water will be formed from [tex]\frac{2}{2}\times 2.61=2.61mol[/tex] of hydrogen gas.

Now, calculating the mass of hydrogen by using equation 1:

Moles of hydrogen gas = 2.61 moles

Molar mass of hydrogen gas = 2 g/mol

Putting values in equation 1, we get:

[tex]2.61mol=\frac{\text{Mass of hydrogen gas}}{2g/mol}\\\\\text{Mass of hydrogen gas}=5.22g[/tex]

Hence, mass of hydrogen gas that must react will be 5.22 grams.

Answer : The kinetic energy is, [tex]3.716\times 10^{3}J/mol[/tex]

Explanation :

The formula for kinetic energy is:

[tex]K.E=\frac{3}{2}RT[/tex]

where,

R = gas constant = 8.314 J/mol.K

T = temperature = [tex]25.0^oC=273+25.0=298.0K[/tex]

Now put all the given values in the above kinetic energy formula, we get:

[tex]K.E=\frac{3}{2}\times (8.314J/mol.K)\times (298.0K)[/tex]

[tex]K.E=3.716\times 10^{3}J/mol[/tex]

Therefore, the kinetic energy is, [tex]3.716\times 10^{3}J/mol[/tex]

Hydrogen bonding, a particularly strong dipole-dipole force, causes a powerful attraction between water molecules, which results in a high boiling point.

Gastrointestinal Tract. Radiation damage to the intestinal tract lining will cause nausea, bloody vomiting and diarrhea. This is occurs when the victim's exposure is 200 rems or more. The radiation will begin to destroy the cells in the body that divide rapidly.

The correct answer is option B, that is, add 1.46 grams of NaCl to 250 milliliters of H₂O.

First there is a need to find the moles of NaCl in 250 ml of 0.10 M NaCl,

Moles of NaCl = molarity × volume = 0.10 M × (250/1000L) = 0.025 mol

The corresponding mass of NaCl is,

Mass of NaCl = moles × molar mass = 0.025 mol × 58.5 g/mol = 1.46 g

Thus, there is a need to dissolve 1.46 grams of NaCl solid into 50 ml of H₂O and dilute to 250 ml.

The most appropriate procedure to prepare a 0.10 M NaCl solution with a volume of 250.0 mL is to dissolve 1.46 g of NaCl in 50 mL of water and dilute to 250 mL.

The most appropriate procedure to prepare a 0.10 M NaCl solution with a volume of 250.0 mL is option D. Dissolve 1.46 g of NaCl in 50 mL of H2O and dilute to 250 mL.

To determine the amount of NaCl needed, we can use the molarity formula:

Molarity = (moles of solute) / (volume of solution in liters)

Using the given molarity of 0.10 M and the volume of 0.250 L (250 mL), we can rearrange the formula to solve for moles of solute:

moles of solute = molarity * volume of solution

Substituting the values, we get:

moles of solute = (0.10 M) * (0.250 L) = 0.025 moles

And finally, we can calculate the mass of NaCl needed using the molar mass:

mass = moles of solute * molar mass

mass = (0.025 moles) * (58.4 g/mol) = 1.46 g

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Answer: the correct answer is

Explanation:

Electrons are the negatively charged particles present inside the atom revolving around the nucleus. These are the subatomic particles of an atom but along with this they also exhibit wave nature explained by french scientist De Broglie.

Photon is discrete packet of energy of an electromagnetic radiation.They exhibit both properties of wave and particle. Photons exhibit's particle nature in photoelectric effect and wave nature in interference experiments.

Hence, the correct answer is option (B).

The movement of charged particles cannot pass through an electrolyte to produce an electric current.

True

False

FALSE

Final answer:

The statement is false. option B

Explanation:

The statement that the movement of charged particles cannot pass through an electrolyte to produce an electric current is false. In fact, electrolytes are substances that can conduct an electric current when dissolved in water or when melted.

Electrolytes contain free ions that move in response to an electric field, which allows them to conduct electricity. For example, when table salt (sodium chloride) is dissolved in water or melted, it becomes an electrolytic solution with ions that readily move, completing an electrical circuit and allowing the current to flow.

Insulators, such as glass, are materials that do not allow charges to move through them effectively. In substances like solid sodium chloride or pure water, the ions are not free to move, making them poor conductors or insulators. However, when these substances are in the form of an electrolyte, the ions are free and mobile, and thus conductivity is observed.

Answer:

Copper and Iron

Explanation:

Metals, like copper and iron, are good conductors of heat; that is because  metals are bounded by a 'cloud' of free electrons and these electrons can carry easily kinetic energy through the metal

On the other hand, foam and wood are isolators, that is, they are bad conductors of heat.

Answer:

B

Explanation:

Answer:

the answer is transition metals

Explanation:

The names of the polyatomic ions match to their symbols as follows: Ammonium - NH₄⁺; Nitrate - NO₃¯; Phosphate - PO₄³¯; Hydroxide - OH¯. Polyatomic ions, which are ions comprising more than one atom, act as individual units in chemical reactions, and they must ensure electrical neutrality in the compounds they form.

In the question, you are required to match the names of different polyatomic ions with their correct symbols. The correct matching for this question is:

Ammonium - NH₄⁺

Nitrate - NO₃¯

Phosphate - PO₄³¯

Hydroxide - OH¯

Polyatomic ions are ions that consist of more than one atom, for instance, nitrate. They behave as a unit in a chemical reaction and have an overall charge.

They are quite common in chemistry and play significant roles in various chemical reactions. In simple ionic compound, electric neutrality is crucial, as seen in the example of calcium phosphate, Ca₃(PO₄)₂.

You determine the neutral charge by treating polyatomic ions as individual units. For instance, in calcium phosphate, the mineral in our bones, we have three calcium ions (Ca²⁺) for each two phosphate (PO₄³¯) groups.

As discreet units, the PO₄³¯ ion has one phosphorus atom and four oxygen atoms with a total charge of 3⁻. The compound is electrically neutral due to the total count of the atoms.

For more such questions on polyatomic ions, click on:

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12.  The answer is; the satellite cools off by radiation

In the vacuum of space, there is no medium for convectional heat transfer. Only electromagnetic radiation transfer energy through space. The satellite will, therefore, lose heat through infra-red radiation, not convection.

13.   The answer is; heat will transfer to her feet by conduction

When the beachgoer wears her sandals, he makes contact with the sandals and his foot and sandal becomes one thermodynamic system.  The heat transfer by conduction, as it passes through the skin, seeks thermal equilibrium.  

15.  The answer is; elastic potential to kinetic

The more the string of the bow is pulled, the higher the elastic potential energy it gains. This is because the string is stretched and has the capacity to restore normal size when released.  When the string is released and begins to rapidly restore, it transfers this energy to the arrow, pushing the arrow forward.

16.    The answer is; Reduced friction means increased efficiency.

By lubricating the moving components of the engine, friction is reduced. Friction causes a loss of energy as the energy is lost through heat as the components rub against one another. Reduction of friction, therefore, reduces this loss and more energy is channeled towards the drive shaft.

17.  The answer is; It increases friction by air resistance.

A parachute is designed to increase drag exceptionally hence reduce the speed of a moving object drastically. Drag is induced by frictional resistance. When the parachute deploys, air is impeded from passing smoothly over the parachute hence enormous air resistance is developed causing the space shuttle to reduce speed.  

This answer explains concepts related to satellite cooling, heat transfer in sandals, potential energy of particles, energy changes in a bow and arrow, and the effect of reducing friction in an engine.

12. When a satellite in space receives no direct sunlight, it cools off by radiation.

13. When a beachgoer leaves her sandals on the shore and puts them back on after swimming, the bottom of her feet feel hot because the sandals were warmed by radiation.

14. In the given scenario, particle C has the greatest potential energy.

15. As a bow is drawn and released, the energy change that occurs is from elastic potential to kinetic.

16. Reducing friction in an engine will result in reduced heat transfer.

17. The parachute helps the space shuttle come to a complete stop during landing by increasing friction by air resistance.

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43 degrees

angle of reflection is equal to the angle of incidence

Answer is: electrons.

According to the Bohr model of the atom:

1. Electrons orbit the nucleus in orbits that have a set size and energy.

2. Energy levels of electrons are discrete (certain discrete values of energy).

3. Electrons can jump from one energy level to another, absorbing or emitting electromagnetic radiation with a frequency ν (energy difference of the levels).

The electron (symbol: e⁻) is a subatomic particle whose electric charge is negative one elementary charge.

Proton is a subatomic particle with a positive electric charge of +1e elementary charge.

Beside negatively charged electrons, atoms have positively charged protons, so atoms have neutral charge.

Answer:

Seeing The 50 N upwards and Ur mom meaning:

Explanation:

Ur Mom banged the 50 N

the answer is the first one aneroid measures air pressure using a metal chamber thats sensitive to pressure changes and is using no liquid.

Aneroid

Aneroid Barometers if anybody have a barometer at home , it is probably an aneroid barometer . The word aneroid means with out liquid .An aneroid barometer has an airtight metal chamber , as shown in figure 6 metal chamber is sensitive to change in air pressure.

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Compounds that are gases at room temperature are covalent bonds (nonmetal + nonmetal).

Final answer:

The state of a substance at room temperature is determined by the strength of intermolecular forces and molecular interactions. Carbon dioxide is a gas at room temperature because of weak intermolecular forces, whereas solids like metals have strong intermolecular forces that give them a definite volume and shape. Compounds exhibit different states under various temperature and pressure conditions.

Explanation:

The physical state of a compound like carbon dioxide at room temperature can be explained by its molecular structure and the interactions between its molecules. Carbon dioxide is a gas at room temperature because the forces between its molecules are relatively weak, allowing them to move freely and occupy the entire volume available to them.

On the other hand, solids at room temperature, such as metals, have strong intermolecular forces that keep their atoms or molecules close together in a fixed, orderly pattern, giving them a definite volume and shape. For a compound to be a liquid at room temperature, its boiling point must be higher than the room temperature, indicating stronger intermolecular forces than gases, but not as strong as solids, thus allowing the molecules to flow while remaining close together.

The state of compounds at room temperature is a significant physical property and is determined by molecular interactions and environmental conditions such as temperature and pressure. All substances can exist in solid, liquid, or gas states under different conditions. For example, carbon dioxide becomes dry ice when cooled to about -78°C, showcasing how temperature changes can alter the state of a substance.