What is Johann Dobereiner's contribution to the development of the periodic table?

Answer:

13.33 g/dm³

Explanation:

Concentration (g/dm³)= mass(g) ÷ volume (dm³)

Now you need to convert 150 cm³ to dm³

1000cm³ = 1 dm³

thus, 150 cm3= 150 ÷ 1000

= 15dm³

and you already have mass in grams

so concentration  = 2 ÷ 0.15

= 13.33 g/dm³ and there you go.. solved ;)

Answer:

4 mol

Explanation:

Given data:

Number of atoms of He = 2.4 × 10²⁴ atoms

Number of moles of He = ?

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

2.4 × 10²⁴ atoms × 1mol / 6.022 × 10²³ atoms

0.398× 10¹ mol

3.98 mol ≅ 4 mol

Answer:

Buffalo and Watertown.

Explanation:

This is correct as the Interior lowlands are located ib the US. These are correct as the others are in the US but aren't located anywhere near the Interior Lowlands.

Answer: Different parts of the sun rotate at different rates.

Explanation:

The statement that best describes the motion of the sun is that different parts of the sun rotate at different rates.

First and foremost, we should note that the rotation of the sun is on its axis and also the sun isn't a solid. Due to this, its motion will be that there'll be rotation of different part of it at different rates. Assuming the sun was solid, then all of its parts will move together.

Answer:

Different parts of the sun rotate at different rates.

Explanation: pic proof

Answer:

Dr. Tierno tested the pillows for signs of microorganisms. He took samples from the pillow, then he grew the microorganisms in a petri dish.

Explanation:

This is the answer on edmentum

In liquid state, the temperature will be 0°C.

D. Liquid

Jet fuels are colorless liquids.

These are colorless liquids that are flammable and smell like kerosene. The fuels are made from chemical compounds called hydrocarbons, which are found naturally in the earth as crude oil. In order for gasoline to freeze it needs to be held at temperatures of around -100 degrees F. Jet fuel cools at the rate of around 3°C per hour, faster in very cold climates.

Thus, correct option is d.

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Answer:

All collisions between particles are perfectly elastic

Explanation:

found it somehwere else

The statement, that describes postulate of the kinetic-molecular theory is "all collisions between particles are perfectly elastic."

A collision would be any process where two or even more objects exert forces on one another quickly.

The kinetic-molecular theory explains matter states and is based on the assumption that matter is made up of small particles that are always in motion. It is a simple, historically significant classical model of the thermodynamic behavior of gases that established several fundamental thermodynamic ideas.

Because the molecules are so small, the kinetic theory of gases assumes that the collision between them is fully elastic. Because the molecules are so small, their energy and momenta are conserved during collisions. As a result, regardless of collisions, the temperature remains constant.

Hence the correct option is all collisions between particles are perfectly elastic.

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#SPJ2

But, an irregular surface, for every bump, the light bounces down up down up down up.

I hope this helped! +*♡

Answer:

0.967mole

Explanation:

Given parameters:

Volume of NH₄Cl  = 21.67L

Unknown:

Number of moles  = ?

Solution:

We assume that the volume was taken at standard temperature and pressure,

 Then;

  Number of moles  = [tex]\frac{volume }{22.4L}[/tex]  

 Number of moles  = [tex]\frac{21.67}{22.4}[/tex]   = 0.967mole

Answer:The height of First Copy is 20 cm.

Step-by-step explanation:

Given:

Original Height = 25 cm

First copy is reduce to 80% of Original height.

Therefore to find the height of first copy can be find out by multiplying 80 with original height and then dividing by 100.

∴ Height of First Copy =

Hence Height of first copy is 20 cm

Now Another copy is reduce to 85% of First Copy.

Therefore to find the height of another copy can be find out by multiplying 85 with first copy height and then dividing by 100.

∴ Height of Another Copy =

Hence Height of Another copy is 17 cm

Explanation:

Answer:

1. 4 km

2. 40 minutes

3. 5 minutes for each km

rlly hope this helps:)

Answer: (4) C-14 to 6-12

Explanation:

Carbon dating is used to estimate the age of wooden trees which use carbon dioxide. Carbon has three naturally occurring isotopes.C-12 and C-13 are stable but C-14 is radioactive. C-14 decays to nitrogen-14 and has a half-life of 5,730 years.

Wooden trees naturally incorporate both the C-12 and C-14 during their lifetimes. When wooden trees die, it stops consuming more of radioactive carbon while the C-14 which is already present in them continues to decay back into nitrogen. With the help of C-12 to C-14 ratio, we can estimate the age of wooden objects.

The age of ancient wooden objects is  investigated using the C-14 to C-12.

Carbon dating provides an effective way to determine the age of a sample. The idea here is that all living organisms give out C-14 while they are alive and the amount of the isotope in a living sample is known.

The age of a sample is obtained by comparing the level of the C-14 isotope present in it to the amount present in a living tissue. Hence, the age of ancient wooden objects is  investigated using the C-14 to C-12.

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1. 4

2. 4

3. 2

4. 2

Given

Reaction

2H₂+O₂⇒2H₂O

Required

Number of atoms

Solution

In compounds, the number of atoms of the constituent components in the form of elements is usually indicated by a subscript after the element symbol, while the number in front of the compound which is the coefficient indicates the number of molecules of the compound.

In chemical reactions, the reactants are on the left and the products on the right

1. Number of Hydrogen in reactants

2 molecules x 2 atoms = 4 atoms

2. Number of Hydrogen in products

2 molecules x 2 atoms = 4 atoms

3. Number of Oxygen in reactants

1 molecules x 2 atoms = 2 atoms

3. Number of Oxygen in products

2 molecules x 1 atoms = 2 atoms

The reaction is said to be balanced because the number of atoms of the element is the same between the reactants and products

Answer:

How many moles H2O in 1 grams? The answer is 0.055508435061792.

We assume you are converting between moles H2O and gram.

You can view more details on each measurement unit:

molecular weight of H2O or grams

This compound is also known as Water or Dihydrogen Monoxide.

The SI base unit for amount of substance is the mole.

1 mole is equal to 1 moles H2O, or 18.01528 grams.

Explanation:

The mass of 4.0 moles of water is 72 grams.

Explanation:

[tex]Moles=\frac{\text{mass of substance}}{\text{molar mass of substance}}[/tex]

Given:

The 4.0 moles of water

To find:

Mass of moles of water

Solution:

The moles of water = 4.0 moles

The mass of water = M

The molar mass of water = 18.01528 g/mol

[tex]4.0=\frac{m}{ 18.01528 g/mol}\\m=4.0\times 18.01528 g/mol\\=72.06112 g\approx 72 g[/tex]

The mass of 4.0 moles of water is 72 grams.

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Answer:

Van der Waals forces is defined as the force that include attraction and repulsions between atoms or molecules, and also involve intermolecular forces

Vander Waals force formed between the similar molecules and not different molecules, that means Van der Waals force  exist between two water molecules and not between hydrogen and oxygen of one molecule. Hydrogen and oxygen are connected with covalent bonds.

Answer:

Each time an excited helium atom falls back from an excited state to its ground state or to a lower energy state, it emits a photon of radiation that shows up as this specific line-emission spectrum.

Explanation:

Answer:

I'm pretty sure its liver and pancreas

Explanation:

the pancreas delivers the digestive juice to the small intestine through small tubes, your liver makes the digestive juices called the bile that helps digest fats and some vitamins

Answer:

the answer is liver and pancreas

Answer:

The level of CO2 in the blood is detected by chemoreceptors located in the aortic arch

and carotid arteries. These send impulses to either the cardioaccelerator or

cardioinhibitor center in the hypothalamus of the brain, which in turn sends an

impulse to the pacemaker of the heart to increase or decrease heart rate. Draw a

feedback diagram to illustrate what happens to restore homeostasis when blood CO2

rises.

Explanation:

The level of CO2 in the blood is detected by chemoreceptors located in the aortic arch

and carotid arteries. These send impulses to either the cardioaccelerator or

cardioinhibitor center in the hypothalamus of the brain, which in turn sends an

impulse to the pacemaker of the heart to increase or decrease heart rate. Draw a

feedback diagram to illustrate what happens to restore homeostasis when blood CO2

rises.

Answer:

NH₄NO₃

Explanation:

In salt naming, the cation is named first, then you must put the name of the anion. In the same way when you are writting the formula. Also, the global charge of a salt is always 0.

Thus, we must write each ion and its charge:

Ammonium: NH₄⁺

Nitrate: NO₃⁻

As both ions have the same charge, the formula is:

The cation first and then the anion.

Answer:

a

Explanation:

Answer:

D

Explanation:

Answer: Fossil fuels are rich in carbon, and burning them releases carbon into the atmosphere.

Explanation:

The amount of carbon in the form of carbon dioxide in the atmosphere is about 0.03% by volume. This value is kept fairly constant by a natural process known as the CARBON CYCLE. This involves carbon dioxide being continually removed from the atmosphere by plants in photosynthesis, rain water as weak acids while in order to maintain this balance, carbon dioxide is at the same time returned to the atmosphere by:

--> burning of carbon containing substances (fossil fuel)

--> respiration of plants and animals and

--> Decomposition of organic substances.

Therefore the role of fossil fuels which are rich in carbon content releases carbon into the atmosphere when burnt.

Answer:

The energy transported by a wave is directly proportional to the square of the amplitude. So whatever change occurs in the amplitude, the square of that effect impacts the energy. This means that a doubling of the amplitude results in a quadrupling of the energy.

Answer:

720 pencils

Explanation:

The parameter given are;

The unit quantity by which the pencils are sold = 1 gross

The number of pencils Daffodil orders = 5 gross of pencils

One gross is a quantity equal to twelve dozens

Therefore, we can write;

1 gross = 12 × 12 = 144

From which we have;

5 gross = 5 × 144 = 720

Which gives;

For the 5 gross of pencils Daffodil orders, she receives 720 pencils

Answer:

He was having a tough time as his mother abandoned him at the age of three or we can say his mother passed which led to his insecurity.

Explanation:

If you look back at the formula ( SO2 ), you can see that there is one sulfur and two oxygens present. Therefore, the molar mass of sulfur dioxide is [1 × 32.1 + 2 × 16.0] = 64.1 g/mol.

Answer:

b

Explanation:

Beryllium is under Group 2, and group 2 are usually known as alkaline earth metals.