What was Johann Dobereiner’s contribution to the development of the periodic table?
He arranged the elements according to increasing atomic mass.
He arranged the elements according to increasing atomic number.
He identified triads of elements that had similar properties.
He organized elements into four groups based on their properties.

A substance in the solid phase (state) of matter has a definite shape and a definite volume.

Volume is the amount of space taken up by an object, while capacity is the measure of an object's ability to hold a substance, like a solid, a liquid or a gas. Volume is measured in cubic units, while capacity can be measured in almost every other unit, including litres, gallons, pounds, etc.

Matter in the solid-state maintains a fixed volume and shape, with component particles (atoms, molecules or ions) close together and fixed into place.

Hence, option A is correct.

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In the reaction CH₄ + 2O₂ → CO₂ + 2H₂O, methane (CH₄) and oxygen (O₂) are the reactants, and carbon dioxide (CO₂) and water (H₂O) are the products. The number of molecules involved is indicated by the numbers in front of the chemical symbols.

In the chemical reaction CH₄ + 2O₂ ightarrow CO₂ + 2H₂O, the reactants are methane (CH₄) and oxygen (O₂), and the products are carbon dioxide (CO₂) and water (H₂O). The arrow signifies the direction in which the reaction proceeds, with the substances on the left side of the arrow being the reactants and the ones on the right side being the products. No reverse arrow is used, indicating the reaction is shown as proceeding in only one direction. The number '2' in front of O₂ and H₂O tells us that there are two molecules of oxygen and two molecules of water involved in the reaction, whereas no number in front of CH₄ and CO₂ indicates only one molecule of each is involved.

The number of Ml  of C₅H₈  that can  be  made  from 366  ml  C₅H₁₂  is 314.7 ml  of C₅H₈

  calculation

 step  1: write  the  equation for  formation of C₅H₈

C₅H₁₂  →  C₅H₈  + 2 H₂

Step 2: find the mass of C₅H₁₂

mass = density × volume

= 0.620 g/ml × 366 ml =226.92 g

Step 3: find moles  Of  C₅H₁₂

moles  = mass÷  molar mass

from periodic table the  molar mass of  C₅H₁₂ = (12 x5) +(  1 x12) = 72 g/mol

moles = 226.92 g÷ 72 g/mol =3.152 moles

Step 4: use the  mole ratio  to determine the  moles of C₅H₈

C₅H₁₂:C₅H₈  is 1:1  from equation above

Therefore the  moles of C₅H₈  is also = 3.152  moles

Step 5: find the mass  of C₅H₈

mass = moles x molar mass

from periodic table the  molar mass of C₅H₈ = (12 x5) +( 1 x8) = 68 g/mol

= 3.152  moles x 68 g/mol = 214.34 g

Step 6: find Ml of  C₅H₈

=mass / density

= 214.34 g/0.681 g/ml = 314.7 ml

You can produce approximately 2.144 mL of C₅H₈ from 366 mL of C₅H₁₂.

This is calculated through conversion of mass using densities of the two substances.

To find out how many milliliters of C₅H₈ can be made from 366 mL of C₅H₁₂, you need to follow these steps:

Therefore, you can produce approximately 2.144 mL of C₅H₈ from 366 mL of C₅H₁₂.

Correct question is: How many milliliters of C₅H₈ can be made from 366 mL C₅H₁₂ ?
density of C₅H₁₂ = 0.620 g/mL
density of C₅H₈ = 0.681 g/mL
density of H₂ = 0.0899g/L

Crystalline solids have a highly ordered, regular structure and distinct melting points. Amorphous solids have randomly arranged particles and melt over a range of temperatures. They're both used extensively in technology.

The primary difference between crystalline and amorphous solids lies in their internal atomic structure. Crystalline solids have their atoms, ions, or molecules arranged in a regular, repeating pattern, forming a lattice. They also have distinct melting temperatures due to the identical attractions their particles experience. Examples of crystalline solids include ionic solids, metallic solids, covalent network solids, and molecular solids.

On the other hand, amorphous solids do not have a well-ordered internal structure. Their particles are arranged randomly, and they soften and melt over a range of temperatures due to the range of interactions their particles experience. Examples of amorphous solids include glasses and certain plastics.

Both types of solids are used extensively in technology, like the silicon crystals in computer chips (a crystalline solid) or the glass in a smartphone screen (an amorphous solid).

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Use the D = M/V equation, in which Density can be found by dividing Mass/Volume.

To solve, first find a rectangular prism tub that is filled to a certain level. Next, place the rock inside to find the amount of displacement (or how high the water level goes up.) In this way, you can find the volume of the rock.

Next, solve for the Mass. This can be found by dividing the total weight from the gravitational pull. This would give you the mass.

Finally, to find Density, divide the Mass found with the Volume. This would give you your final answer

~

The correct answer is option A, that is, transport fluid.  

The lymphatic system refers to a network of organs and tissues, which helps in getting rid of the body wastes, toxins, and other undesired elements. However, the main activity of the lymphatic system is to transport lymph, that is, a fluid comprising infection-fighting white blood cells, all through the body.  

The lymphatic system mainly comprises of lymphatic vessels that are identical to the circulatory system's capillaries and veins. The vessels are associated with lymph nodes, where the filtration of lymph is done. The adenoids, tonsils, thymus, and spleen are all the components of the lymphatic system.  

The confirmation of new scientific findings is achieved through repeated experiments that yield consistent results. This process is central to the scientific method and ensures the reliability of scientific discoveries.

It is important to confirm new scientific findings through repeated experiments that produce consistent results. This concept is at the heart of scientific method, a systematic approach to inquiry that aims to minimize of bias and maximize the reliability of findings. Repeating experiments helps to ensure that findings are not due to random chance, experimental errors, or biases. By producing consistent results, we increase the confidence that the findings accurately represent what they are intended to measure, making them more reliable. Thus, replication and reliability are crucial for scientific progress.

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Answer:

Explanation:

multiple investigations; consistent results

Cells are considered the fundamental units of life. The cells in complex multicellular organisms like people are organized into tissues, groups of similar cells that work together on a specific task. ... At each level of organization—cells, tissues, organs, and organ systems—structure is closely related to function.

Cells are the basic units of life that join together to form tissues, which in turn combine to form organs. These organs, working together, form organ systems and eventually, an organism. Understanding the relationships between cells, tissues, and organs is fundamental in studying biological structures.

Cells, tissues, and organs are closely related, as they form the building blocks of all organisms. Cells are the smallest unit of life, and in multicellular organisms, these cells of a similar kind interconnect with each other and perform shared functions to form tissues (for example, muscle tissue, connective tissue, and nervous tissue). Then, several tissues combine together to form an organ (like the heart, brain, or stomach) that carries out a specific function.

Organ systems, such as the circulatory or digestive system, are made up of several organs working in unison. These organ systems functioning together form an organism, like a human or an elephant. Understanding the structure and function of cells helps in the study of tissues, and similarly, understanding tissues aids in comprehending how organs function.

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Answer: 3 times lesser

     a and b are inversely proportional,

                                                a ∝ (1/b)

                                                or a  =  k/b                 where k =constant ,

                                             if a is 3 times increased  what happens to b ?

                                                  b is 3 times less.

Beryllium.

All four elements are found in the second column to the left of a periodic table. They are group 2 elements.

The 1st ionization energy generally decrease down each group.

Elements in each group have the same number of electrons in the outermost occupied electron shell. Electrons in the inner shell shield those in the outer shell from attractions from the nucleus, known as the shielding effect. The number of protons in each atom increase by more than 8 in each period. However, due to this effect, electrons in the outermost shell experience a far weaker force pulling them towards the center of the atom. For atoms of the four group 2 elements, electrons in the outermost layer would behave as if there's only two protons inside their nucleus. As a result, their end up with rather similar ionization energies.

Despite the same effective charge on each electron, the mean radius of the electrons increase down the group. Beryllium is in the second period; its electrons occupy only two electron shells in the ground state. On the contrary, strontium is in the fifth period; its electrons occupy up to five electrons shells in its ground state. The strength of electrostatic attraction decreases as the two charges move apart. As a result, outermost electrons in beryllium are way more attached to the nucleus than those in strontium.

FYI, the 1st ionization energy of the four elements are shown below:

The element with the highest first ionization energy among the choices is; Beryllium, Be

The ionization energy of an element is the energy required to remove one of the electrons in its outermost shell.

The first ionization energy of elements is inversely proportional to the atomic radii of elements.

This is so because a lesser atomic radius corresponds to greater electrostatic attraction between the electron and the nucleus of the atom.

We must also state that the atomic radius of elements in the periodic table increases down a group and decreases across a period.

In essence, the smaller the atom of an element, the larger is its first ionization energy.

The element with the highest first ionization energy is the smallest element and is therefore Beryllium, Be.

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Answer:

B. It was deliberately set!

Explanation:

Just took the test and it was right!

The  number of molecules of isopently acetate is  4.63  x 10¹⁵  molecules

 calculation

Step 1:  find the moles of isopently acetate( C₇H₁₄O₂)

moles  =  mass÷  molar mass

From periodic table the molar mass of C₇H₁₄O₂

= (12 x7 ) + (1 x14) +(16 x2) =130 g/mol

moles = 1 x10⁻⁶ g÷ 130 g/mol =  7  x 10⁻⁹ moles

step 2 ; use the Avogadro's  law  constant to calculate the number of molecules

That  is according to Avogadro's law  1 mole  = 6.02 x 10²³  molecules

                                                          7 x 10⁻⁹ moles = ?  molecules

by cross multiplication

= { (7 x 10⁻⁹ moles x  6.02 x10²³  molecules) / 1  mole} = 4.63 x 10¹⁵  molecules

To determine the number of molecules of isoamyl acetate in a 1x10⁻⁶g bee sting, calculate the molar mass, convert mass to moles, and multiply by Avogadro's number to find approximately 4.625x10¹⁵ molecules.

To determine how many molecules of isoamyl acetate (isopentyl acetate) C₇H₁₄O₂ are released in 1x10⁻⁶g during a typical bee sting, we first need to calculate the molar mass of C₇H₁₄O₂. The molar mass is given by the sum of the atomic masses of all the atoms in one molecule of the substance. This is calculated as:

7 carbons (C) times 12.01 g/mol = 84.07 g/mol

14 hydrogens (H) times 1.008 g/mol = 14.112 g/mol

2 oxygens (O) times 16.00 g/mol = 32.00 g/mol

Adding these together gives a molar mass of 130.182 g/mol for isoamyl acetate.

Next, we use the following formula to convert the mass of the substance to moles:
moles = mass (g) / molar mass (g/mol)
= 1x10⁻⁶g / 130.182 g/mol
moles = 7.68x10⁻⁹ moles of C₇H₁₄O₂.
Finally, to find the number of molecules, we multiply the moles of the substance by Avogadro's number (6.022x10²³ molecules/mol):
number of molecules = 7.68x10⁻⁹ moles x 6.022x10²³ molecules/mol
number of molecules = 4.625x10¹⁵ molecules of C₇H₁₄O₂.
The number of molecules of isoamyl acetate released in 1x10⁻⁶g during a typical bee sting is approximately 4.625x10¹⁵.

Photons are units or packets of electromagnetic energy. They carry no charge or mass.

While, electrons are constituents of an atom that are negatively charged and associated with a certain mass. In fact, electrons in an atom can get excited when they absorb photons of characteristic energy from electromagnetic radiation.

The similarity between photons and electrons is that both can behave as particles as well as waves.

Ans B

I Believe it would be 46.005500

hoped this helped let me know if I'm wrong

Answer: The mass of nitrogen dioxide for given number of moles are 158.7 grams.

Explanation:

To calculate the mass for given number of moles, we use the equation:

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

We are given:

Moles of nitrogen dioxide = 3.45 moles

Molar mass of nitrogen dioxide = [tex][14+(2\times 16)]=46g/mol[/tex]

Putting values in above equation, we get:

[tex]3.45mol=\frac{\text{Mass of }NO_2}{46g/mol}\\\\\text{Mass of }NO_2=(3.45mol\times 46g/mol)=158.7g[/tex]

Hence, the mass of nitrogen dioxide for given number of moles are 158.7 grams.

Answer:

Honey

Explanation:

Backing soda:

Backing soda is a compound that is made up of only one kind of salt called NaHCO3 or sodium  hydrogen carbonate. All the molecules  of NaHCO3  are identical and we know that a mixture is something made up of two or more than two kinds of things, therefore baking soda cannot be referred to as mixture.

Carbon:

Carbon is not a mixture because its just an element that composed diffreent compounds by reacting with different other elements. In its oure form carbon is not a mixture, but if it is combined with some other substance it can form mixture.

Orange juice:

It depends on what kind of orange juice we are talking about. If we are talking about pure orange juice that is made from fresh oranges,then no - it cannot be called as mixture. However, if sugars,flavors and other preservatives are added like those available in market then it can be a mixture.

Honey:

Honey is a mixture of at-least 181 types of components in which most of all are sugars. These components mix through complex process and give the honey its specific sugary taste. You can see some of the constituent components of honey in attached figure.

Hope it help!

 The statement  which  is true  about  the reactivity  of  element  with          1S²2S²2P⁶3S¹   is

 it is reactive   because it has to lose one  electron  to have  a full  outermost  energy  level.

Explanation

Answer:

C. It is reactive because it has to lose one electron to have a full outermost energy level.  

480 nm

Explanation:

The key to any frequency and wavelength problem is the fact that frequency and wavelength have an inverse relationship described by the equation

Answer:

10.3 °C

Step-by-step explanation:

This is an isolated system so

heat gained by ice + heat lost by water = 0

Heat to warm ice + heat to melt ice + heat to warm melt + heat lost by water = 0

     q₁     +     q₂        +      q₃      +     q₄      = 0

n₁C₁ΔT₁ + n₁ΔH_fus + n₁C₃ΔT₃ + n₄C₃ΔT₄  = 0

Step 1: Calculate q₁

n₁ = 40.0 g × 1/18.02

n₁ = 2.220 mol

C₁ = 37.7 J·K⁻¹mol⁻¹

ΔT₁ = T_f – T_i  

ΔT₁ = 0.0 – (-15)

ΔT₁ = 15 °C = 15 K

q₁ = 2.220 × 37.7 × 15  

q₁ = 1255 J

q₁ = 1.255 kJ

===============

Step 2. Calculate q₂

ΔH_fus = 6.01 kJ·mol⁻¹

q₂ = 2.220 × 6.01

q₂ = 13.34 kJ

===============

Step 3: Calculate q₃

C₃ = 75.3 J·K⁻¹mol⁻¹

ΔT₃ = T_f – T_i  = x – 0 °C  

ΔT₃ = x °C = x K

q₃ = 2.220 × 75.3 × x

q₃ = 167x J

q₃ = 0.167x kJ

===============

Step 4. Calculate q₄

n₄ = 265 × 1/18.02

n₄ = 14.71 mol

ΔT₄ = T_f – T_i  = x – 25.0 °C  

q₄ = 14.71 × 75.3 × (x – 25.0)

q₄ = 1107 × (x – 25.0)

q₄ = 1107x  – 27 680 J

q₄ = 1.107x – 27.68 kJ

===============

Step 5. Solve for x

1.255 + 13.34 + 0.167x + 1.107x - 27.68 = 0

1.274x - 13.08 = 0

1.274x = 13.08

x = 13.08/1.274

x = 10.3 °C

The final temperature is -10.3 °C.

Answer:

1-chloro-3-ethyl-2,2-dimethylheptane  

Step-by-step explanation:

Here are the rules for naming alkyl halides.

1. Find the longest continuous chain of carbon atoms (see image below).

There are two different seven-carbon chains.

2. If two or more chains are competing for selection as the main chain, select the one that has more substituents.

We choose the chain marked by the blue line .

3. Name the main chain.

The chain has seven C atoms, so its base name is heptane.

4. Identify and name all the substituents.

There are one Cl atom (chloro), two 1C groups (methyl),  and one 2C group(ethyl)

5. Number the main chain from the end closest to a substituent.

The C bearing the Cl atom becomes C-1.

5. Identify the substituents by the number of the C atom on the main chain (the locant). Use hyphens between letters and numbers (1-chloro, 2-methyl, 3-ethyl).

6. If there are two or more identical substituents, give the locant for each and use a multiplying prefix. Use commas between two numbers (2,2-dimethyl).

7. Put the names of the substituents with their locants in alphabetical order in front of the base name with no spaces.

The IUPAC name is 1-chloro-3-ethyl-2,2-dimethylheptane.

The product of the chemical reaction 2 H₂ + O₂ → 2 H₂O is water (H₂O), which is a result of two moles of hydrogen reacting with one mole of oxygen.

The product of the chemical reaction 2 H₂ + O₂ → 2 H₂O is water (H₂O). This represents a composition reaction where two molecules of hydrogen gas (H₂) react with one molecule of oxygen gas (O₂) to produce two molecules of water (H₂O). A key point to remember is that balanced chemical equations reflect not only the molecular count but also the molar amounts of the substances involved. Hence, we can say that two moles of hydrogen react with one mole of oxygen to yield two moles of water.

c, 1A hope this helps

Answer:C

Explanation:

Alkali metals are those elements found in group 1A. They are the very first elements one encounters at the extreme left hand side of the periodic tab!e. They are extremely reactive and are the most electro positive of all the metals. They include; Li, Na, K Rb, Cs, Fr.

Answer:

The answer A.The product of a combustion reaction

Explanation:

A catalyst is the substance which helps in increasing the rate of a reaction without itself getting consumed in the reaction.

A catalyst changes the path of reaction so that molecules with lower energy can easily participate in the reaction. As a result, formation of products increases.

Thus, we can conclude that out of the given options, a catalyst is not used up in a reaction.

A covalent bond holds two atoms close together because electrons in their outermost orbitals are shared by both atoms.

There are two types of chemical compound one is covalent compound and another is ionic compound in chemistry. Therefore, a covalent bond holds two atoms close together because electrons in their outermost orbitals are shared by both atoms.

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

Covalent compounds are formed by covalent bond and ionic compounds are formed by ionic bond. Covalent bond is formed by sharing of electron and ionic bond are formed by complete transfer of electron. Ionic bonds are stronger than covalent bonds.

The melting and boiling points are higher in ionic compounds. A covalent bond holds two atoms close together because electrons in their outermost orbitals are shared by both atoms.

Therefore, a covalent bond holds two atoms close together because electrons in their outermost orbitals are shared by both atoms.

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I belive it is thermal energy...

Answer:

The Correct Answer is B

Thermal energy

Explanation:

Answer:

11

Explanation:

the atomic number is the same as the number of electrons

If we are talking about BOTH the pieces surface areas the answer would be A. Greater than. This is because a split cube has an extra side on each piece that the original cube didn't have.

I hope that helps!!

If a cube is split in half, the surface area of the pieces will be greater than that of the cube.

If a cube is split in half, the surface area of the pieces will be greater than that of the cube. This is because when you cut the cube, you are adding two more faces (the cut faces), which increases the total surface area. Let's explore an example using a cube of side length 2 units:

Original cube surface area = 6 faces  imes (2 units  imes 2 units) = 24 square units.

When split, each half has 5 faces of 4 square units (original cube's faces) and 1 new face of 4 square units (from the cut), totaling 6 faces.

So, each half has a surface area of 6 faces  imes 4 square units = 24 square units.

For both halves combined: 24 square units + 24 square units = 48 square units.

Comparing the original cube's surface area (24 square units) with the combined surface area of the two halves (48 square units), we can conclude that the surface area is increased after cutting the cube.

Density ρ=[tex]\frac{m}{v}[/tex]

=[tex]\frac{2.56 kg}{0.820 L} \\=3.121kg/L[/tex]