Someone please help me plz :(please

Answer:

The elements of group 18 of the periodic table are known as noble gases or inert gases.

Explanation:

The noble gases are placed in group 18 of the periodic table.  These gases have a very low chemical reactivity, that is, little combination with other elements of the periodic table. For that reason they are called inert gases. This behavior is due to its electronic configuration, because its outermost layer or valence layer is always complete, being the stable element by itself, without the need to borrow or share electrons.

As mentioned, noble gases are not very reactive, that is, they do not usually form bonds between atoms. This means that they don't react much with other substances, they don't even react between atoms of the same gas.

In summary, the elements of group 18 are non-reactive elements.

Finally, the elements of group 18 of the periodic table are known as noble gases or inert gases.

Answer:

2.7724 g

Explanation:

Mass of pre- 1892 pennies = 3.1 g

Abundance = 45.4 %

Mass of post 1892 pennies = 2.5 g

Abundance = 100 - 45.4 = 54.6 %

The average mass is given as = ( 3.1 g   *  45.4 / 100)  +  (2.5g  *  54.6 / 100)

Average Mass = 3.1 * 0.454   +   2.5  *  0.546

Average Mass = 1.4074  + 1.365 = 2.7724 g

Answer:

the answer is c I tink good luck

Answer:

C. Warm surface water is reduced, causing colder conditions than normal.

Explanation:

During El Niño, trade winds are weak. During La Niña, it's the opposite. The surface winds across the entire tropical Pacific are stronger than usual, and most of the tropical Pacific Ocean is cooler than average. Rainfall increases over Indonesia (where waters remain warm) and decreases over the central tropical Pacific

Explanation:

rain, snow, cloud, fog or dry deposition - Dry particles, or gas

Answer:

unit cells; lattice

Explanation:

Answer:

c. 12

Explanation:

Oxygen has six valance electrons

Silicon has six valance electrons

There are a number of possible atomic numbers but all come from the VI A group of elements.

so i think that is your answer base on the statement given above hope that helps thanx

Answer:

If the material is opaque, light is reflected or absorbed. If the material is transparent, all light is transmitted. If the material is translucent, the light is scattered. The higher the frequency, the more energy the light waves have. The lower the frequency, the less energy the light waves have.

Explanation:

I'm literally learning about it right now and I got it right.

Particles in a metal are held together by Covalent attractions. These are the strongest attraction or types of bonding

The bonds that hold atoms together to form molecules are called covalent bonds. They are pretty tough and not easily made or broken apart. It takes energy to make the bonds and energy is released when the bonds are broken.

For example, there is a covalent bonding between a Chlorine molecule. the two chlorine atoms are held strongly via covalent bonds.

Find more information about Covalent bonding here:

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Answer:

d

Explanation:

i think its d but im not sure.

Answer:

Neither

Explanation:

None of the answer choices is the correct definition of erosion. Erosion is actually the removal of weathered materials and particle from the surface of rocks and soils.

Erosion is a serious problem in Agriculture as it removes rich and fertile soil cover. This therefore renders the soil barren and stripped of available nutrients.

Answer:

The process of breaking down rock and soil.

Explanation:

Answer:

12

Explanation:

The answer is 12 because You are looking for hydrogen which is the big H. you look to the number below it and it is 12. So H stands for hydrogen and there are 12 Hydrogen getting you your answer of 12.

Answer:

sperm cell

Explanation:

The male portion of a zygote is called the sperm cell. The sperm cell are produced by the male organism and they fertilize the eggs.

Answer:

10 m/s

Explanation:

100 meters covered in 10 seconds, so:

100 m / 10 s = 10 m/s

Answer:

A

Explanation:

Sana makatulong tong answer ko

The total number of molecules in 34.0 g of ammonia is equal to 12.044×10[tex]^23[/tex] molecules according to the concept of Avogadro's number.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.

In the given example,number of molecules is determined as follows,

17 g ammonia has 6.022×10²³ molecules

So,34 g ammonia has, 34×6.022×10²³/17=12.044×10²³ molecules.

Hence, the total number of molecules in 34 g of ammonia is 12.044×10²³ molecules.

Learn more about Avogadro's number ,here:

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#SPJ6

Your question is incomplete, but the most probable answer is 12.044×10²³ molecules.

Answer:

yes

Explanation:

Answer:

im pretty sure! good job :))

Explanation:

im sorry if it isnt in advance, hope this helped a little!

Answer:

0.0584 M

Explanation:

From the question given above, the following data were obtained:

Mass of CaCl₂ = 0.808 g

Volume of water = 250 mL

Concentration of chloride =?

Next, we shall determine the number of mole in 0.808 g of CaCl₂. This can be obtained as follow:

Mass of CaCl₂ = 0.808 g

Molar mass of CaCl₂ = 40 + (35.5 × 2)

= 40 + 71

= 111 g/mol

Mole of CaCl₂ =?

Mole = mass / Molar mass

Mole of CaCl₂ = 0.808 / 111

Mole of CaCl₂ = 0.0073 mole

Next, we shall convert 250 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

250 mL = 250 mL × 1 L / 1000 mL

250 mL = 0.25 L

Next, we shall determine the molarity of CaCl₂. This can be obtained as follow:

Mole of CaCl₂ = 0.0073 mole

Volume of water = 0.25 L

Molarity of CaCl₂ =?

Molarity = mole /Volume

Molarity of CaCl₂ = 0.0073 / 0.25

Molarity of CaCl₂ = 0.0292 M

Finally, we shall determine the concentration of the chloride as illustrated below:

CaCl₂ <=> Ca²⁺ + 2Cl¯

From the equation above,

1 mole of CaCl₂ produced 2 mole of Cl¯.

Therefore, 0.0292 M CaCl₂ will produce = 0.0292 × 2 = 0.0584 M Cl¯.

Thus, the concentration of the chloride ion (Cl¯) in the solution is 0.0584 M

Answer:

The energy stored in the spring when the bike goes over a bump is [tex]6.6\times 10^{-3}[/tex] joules.

Explanation:

Let suppose that spring has a linear behavious, by means of Hooke's Law, definition of Work and Work-Energy Theorem we find that the potential energy stored in the spring ([tex]U_{g}[/tex]), measured in joules, is defined by:

[tex]U_{e} = \frac{1}{2}\cdot k\cdot x^{2}[/tex] (1)

Where:

[tex]k[/tex] - Spring constant, measured in newtons per meter.

[tex]x[/tex] - Deformation, measured in meters.

If we know that [tex]k = 33\,\frac{N}{m}[/tex] and [tex]x = 0.02\,m[/tex], the energy stored by the spring due to compression is:

[tex]U_{e} = \frac{1}{2}\cdot \left(33\,\frac{N}{m} \right) \cdot (0.02\,m)^{2}[/tex]

[tex]U_{e} = 6.6\times 10^{-3}\,J[/tex]

The energy stored in the spring when the bike goes over a bump is [tex]6.6\times 10^{-3}[/tex] joules.

Explanation:

Work done = Force * Diatance

By applying this equation,

We have Work Done = (6.0N)(0.3m) = 1.8J.

Answer:

Explanation:

Formula used : Work = Force × Displacement

Work done = 6.0 Newton×0.3 meters = 1.8 joules

Heating a gas increases the kinetic energy of the particles, causing the gas to expand. In order to keep the pressure constant, the volume of the container must be increased when a gas is heated.

As you know, the stoichiometric coefficients attributed to each compound in the balanced chemical equation can be thought of as moles of reactants needed or moles of products formed in the reaction. Notice that the reaction requires 2 moles of hydrogen gas and 1 mole of oxygen gas to produce 2 moles of water.

I'm not exactly sure if this is right, but I still hope this helps none the less ^^

6 moles of H2O are produced from 3 moles of oxygen.

We know that one mole of water is formed from a half mole quantity of oxygen gas so in this way 3 moles of water is produced from using 1.5 moles of oxygen atom so we can conclude that 6 moles of H2O are produced from 3 moles of oxygen.

Learn more about mole here:https://brainly.com/question/1427235

Answer:

Yes, it does have an important role in humanity!

Explanation:

In human life, refraction of light plays an important role. It has many applications in optics and imaging technology. Some of the applications are: Refraction concave and convex glasses are used to correct the refractive errors of human eyes.

its use full to humanity if you stay back jk

Answer:

C = 107.97 mol/L

Explanation:

Given data:

Volume of solution = 1.38 mL (1.38 mL× 1 L /1000 mL = 0.00138 L)

Mass of ammonium sulfite = 17.36 g

Concentration of solution =?

Solution:

We will calculate the number of moles of ammonium sulfite.

Number of moles = mass/molar mass

Number of moles = 17.36 g / 116.15 g/mol

Number of moles = 0.149 mol

Concentration/molarity:

C = n/V

C = 0.149 mol / 0.00138 L

C = 107.97 mol/L

The question is incomplete, the complete question is;

Why is a terminal alkyne favored when sodium amide (NaNH2) is used in an elimination reaction with 2,3-dichlorohexane? product. A) The terminal alkyne is more stable than the internal alkyne and is naturally the favored B) The terminal alkyne is not favored in this reaction. C) The resonance favors the formation of the terminal rather than internal alkyne. D) The strong base deprotonates the terminal alkyne and removes it from the equilibrium.

E) The positions of the Cl atoms induce the net formation of the terminal alkyne.

Answer:

E) The positions of the Cl atoms induce the net formation of the terminal alkyne.

Explanation:

In this reaction, sterric hindrance plays a very important role. We know that sodamide is a strong base, it tends to attack at the most accessible position.

The first deprotonation yields an alkene. The strong base attacks at the terminal position again and yields the terminal alkyne. Thus the structure of the dihalide makes the terminal hydrogen atoms most accessible to the base. Hence the answer.

Answer:

The alcohol is a primary alcohol.

Explanation:

Chromic acid oxidizes primary alcohols to carboxylic acids and secondary alcohols to ketones but does not react with tertiary alcohols under mild conditions. Therefore, from the Chromic acid test, the class of alcohol is either primary or secondary.

Lucas reagent (a solution of anhydrous ZnCl₂ in conc. HCl)

Primary alcohols do not react readily at room temperature with the Lucas reagent, secondary alcohols react after some minutes while tertiary alcohols react immediately.

Since the alcohol is oxidized by chromic acid and does not react with Lucas reagent, it is a primary alcohol.

A solution of anhydrous zinc chloride in hydrochloric acid is called the Lucas reagent. The alcohol that does not react with Lucas's reagent is a primary alcohol.

The primary alcohol is the compounds that have their hydroxy group (-OH) attached to the primary carbon atom. Its molecular formula is, [tex]\rm CH_{2}OH[/tex].

The hydroxyl carbon of the primary alcohol contains only one R group in its structure. Methanol and ethanol are examples of primary alcohol.

Primary alcohol does not react with Lucas's reagent and no turbidity is formed as carbocation of the primary alcohol is too unstable.

Therefore, primary alcohol does not react with Lucas reagent.

Learn more about primary alcohol and Lucas reagent here:

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Answer:

The mass of ammonium nitrate that has the same number of nitrogen atoms is 5077.5 g.

Explanation:

To calculate the mass of ammonium nitrate we need to find the number of atoms in liquid nitrogen, as follows:

[tex]d_{N} = \frac{m_{N}}{V}[/tex]

Where:

[tex]d_{N}[/tex]: is the density of liquid nitrogen = 0.808 g/mL

[tex]m_{N}[/tex]: is the mass of liquid nitrogen

V: is the volume of liquid nitrogen = 2.2 L

By calculating the mass of liquid nitrogen we can find the number of atoms:

[tex]m_{N}=d_{N}*V = 0.808 g/mL*\frac{1000 mL}{1 L}*2.2 L=1777.6 g[/tex]

[tex]n = N_{A}*\eta_{N}[/tex]

[tex]n=N_{A}*\frac{m_{N}}{M_{N}}[/tex]

Where:                

[tex]N_{A}[/tex]: is the Avogadro's number = 6.022x10²³ atoms/mol

n: is the number of atoms of liquid nitrogen

[tex]\eta_{N}[/tex]: is the number of moles of liquid nitrogen  

[tex]M_{N}[/tex]: is the molar mass of liquid nitrogen = 28.014 g/mol

[tex]n = \frac{6.022 \cdot 10^{23} atoms}{1 mol}*\frac{1777.6 g}{28.014 g/mol} = 3.82 \cdot 10^{25} atoms[/tex]

Finally, the mass of ammonium nitrate is:

[tex]m_{NH_{4}NO_{3}} = \frac{n*M_{NH_{4}NO_{3}}}{N_{A}}[/tex]

Where:

[tex]M_{NH_{4}NO_{3}}[/tex]: is the molar mass of ammonium nitrate = 80.043 g/mol

[tex] m_{NH_{4}NO_{3}} = \frac{3.82 \cdot 10^{25} atoms*80.043 g/mol}{6.022 \cdot 10^{23} atoms/mol} = 5077.5 g [/tex]

Hence, the mass of ammonium nitrate that has the same number of nitrogen atoms is 5077.5 g.

I hope it helps you!                                                            

Answer:

That the isotope H-1 is the most abundant in nature.

Explanation:

Hello!

In this case, since the average atomic mass of an element is computed considering the mass of each isotope and the percent abundance each, for hydrogen we would set up something like this:

[tex]m_H=m_{H_1}*\%abund_{H_1}+m_{H_2}*\%abund_{H_2}[/tex]

Moreover, since the isotope notation H-1 and H-2 means that the atomic mass of H-1 is 1 amu, that of H-2 is 2 amu and the average one is 1.0079 amu, we can infer that the most of the hydrogen in nature is H-1 as the most of it composes the average hydrogen atom.

Best regards!

Answer:

D.

Explanation:

Well waves forming in not an indication of a phase change, neither is splashing water. Water soaking into the sand could be a form of change, from condensation into precipitation but that is not what the example is speaking of. The change from water into vapor can be indicated by the loss of water in liquid form.

Answer:

[tex]\mathbf{C_4 H_{8}O_{4}}[/tex]

Explanation:

From the given information:

Assume the molecular formula to be: [tex]C_a H_{2a} O_{a}[/tex]

Then, the molecular mass will be = 12a + 2a + 16a = 30a  (since the C = 12, H = 2 & O = 16) respectively.

Thus;

30a = 120

a = 120/30

a = 4

Thus, the molecular formula:

[tex]=C_4 H_{2*4} O_{4}[/tex]

[tex]= \mathbf{C_4 H_{8}O_{4}}[/tex]