HELPPP ANSWERS ????

A: 3
B: 2
C: 1
D: 4

Answer:

Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.

Explanation:

Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Hence, option C is correct.

Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.

Substances made of wood, such as paper and cardboard, are also flammable.

Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.

They include reactivity, flammability, and the ability to rust.

Hence, option C is correct.

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Answer:

The term Decimal is coined from the word Decimus. Decimus is a Latin word which means ‘tenth’.

The Decimal system is a system of numbering that is based on multiples of tens. It is flexible and easy to convert from one metric to another.

The preference of the term over the Metric System is because the word Metric is related more to the measurement of lengths if we looked at the origin of the word which is French.

Cheers!  

Answer:

24.0g H2O

Explanation:

1.33 mol (18.016g/1 mol) = 24.0g H2O

Answer:

C. The particles in a gas are spread farther apart than the particles in a solid

Explanation:

Solids are made up of tightly-packed particles that form a rigid shape. Liquids are comprised of loosely connected particles that can slightly move. Gases are made up of fast-moving disconnected particles that are spread far apart.

Answer:

    The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.

Answer:

4

Explanation:

there is a decimal place present. so you would take away any zeros before the number.

Answer:

4 i think

Explanation:

Answer:

-a nonmetal is a substance that lacks the characteristics of a metal.

-Seventeen elements are generally classified as nonmetals: most are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon); one is a liquid (bromine); and a few are solids (carbon, phosphorus, sulfur, selenium, and iodine).

Answer:

344.5764 torr

Explanation:

Molar mass of naphthalene = 128.2g/mol

Mass of naphthalene = 10.60 g

Carbon disulfide:

Molar mass= 76.14g/mol ;

volume = 155mL ;

density = 1.261 g/mL

Vapour pressure = 355.6 torr

Number of moles = mass / molar mass

CS2:

Mass = density × volume

Number of moles = (density × volume) / molar mass

Number of moles = (1.261 * 155) / 76.14 = (195.455 / 76.14) = 2.567 moles of CS2

Number of moles of C8H10:

Number of moles = 10.60 / 128.2 = 0.083 C8H10

Total number of moles :

2.567 + 0.083 = 2.65 moles

Mole fraction of each compound in solution :

CS2 :

2.567 / 2.65 = 0.969

C8H10:

0.083 / 2.65 = 0.031

According to Raoult's:

Psolution = Xsolvent × Posolvent

CS2 = solvent

Xsolvent = Mole fraction of solvent

Posolvent = Vapour pressure of pure solvent

Psolution = 0.969 × 355.6 torr = 344.5764 torr

The vapor pressure of the solution would be as follows:

[tex]344.5764[/tex] torr

Given that,

Vapor pressure of Carbon Disulfide [tex]= 355.6[/tex] torr

[tex]volume = 155mL ;[/tex]

[tex]density = 1.261 g/mL[/tex]

Naphthalene's mass [tex]= 10.60 g[/tex]

Naphthalene's molar mass [tex]= 128.2g/mol[/tex]

Now,

We know that

Number of moles [tex]= mass/molar mass[/tex]

Mass [tex]= density[/tex] × [tex]volume[/tex]

[tex]Number of moles =[/tex] [tex](density[/tex] × [tex]volume) / molar mass[/tex]

So,

Number of moles of Carbon Disulfide [tex]= (1.261[/tex] × [tex]155) / 76.14[/tex]

[tex]= (195.455 / 76.14)[/tex]

[tex]= 2.567[/tex] moles of Carbon Disulfide

Number of moles of Naphthalene:

Number of moles [tex]= 10.60 / 128.2[/tex]

[tex]= 0.083[/tex]

Now,

Total number of moles :

[tex]2.567 + 0.083[/tex]

[tex]= 2.65[/tex] moles

Mole fraction of each compound in solution :

Carbon Disulfide:

2.567 / 2.65

[tex]= 0.969[/tex]

Naphthalene

0.083 / 2.65

[tex]= 0.031[/tex]

According to Raoult's:

P[tex]solution = Xsolvent[/tex] × [tex]Posolvent[/tex]

Carbon Sulfide = Solvent

[tex]Xsolvent =[/tex] Mole fraction of solvent

[tex]Posolvent =[/tex] Vapour  pressure of the pure solvent

[tex]Psolution[/tex] [tex]= 0.969[/tex] × [tex]355.6 torr[/tex]

[tex]= 344.5764[/tex] torr

Thus, "[tex]344.5764[/tex] torr" is the correct answer.

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Answer:

Explanation:

An acid is a substance that, when dissolved in water produces hydrogen ions, H⁺ as the only positive ion. e.g.

HCl       ↔    H⁺   +   Cl⁻

HNO₃    ↔   H⁺   +  NO⁻₃

This process is known as ionization. The characteristics properties of an acid in solution are due to the presence of these hydrogen ions. In these reactions, the negative ions formed or sometimes the neutral compounds are usually known as the conjugate base of such acid.

From the given information, the conjugate base of the acid given can be seen in the attached image below.

The conjugate base for the acid is attached below.

An acid is a substance that, when dissolved in water produces hydrogen ions, H⁺ as the only positive ion. e.g.

HCl       ↔    H⁺   +   Cl⁻

HNO₃    ↔   H⁺   +  NO⁻₃

This process is known as ionization. The characteristics properties of an acid in solution are due to the presence of these hydrogen ions. In these reactions, the negative ions formed or sometimes the neutral compounds are usually known as the conjugate base of such acid.

The conjugate base of the acid given can be seen in the attached image below.

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A substance that cannot be converted into another substance is known as an element. Each type of atom that makes up an element is unique. The correct option is A.

A substance whose atoms all contain the same number of protons is said to constitute an element; alternatively, all the atoms of a certain element must contain the same number of protons. Chemical reactions cannot degrade elements since they are the simplest chemical forms.

A compound is created when two or more components join chemically in a predetermined mass ratio.

Thus the correct option is A.

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Answer:

Explanation:

the formula of the compound containing sodium and oxide ion is

NaOH the charge on sodium is partial positive and the charge on hydroxide ion is partial negative

another compound containing sodium and oxide ion is Na2O here the charge on sodium oxide is neutral

Answer:

+2.

Explanation:

Hello,

In this case, since chromium has six valence electrons in its outer shell, when it loses four electrons it remains with two of them, therefore it charge as chromium ion is +2, so it is written as Cr⁺² and named as chormium (II) or hypochromous ion.

Best regards.

Answer:

First, the direct method requires recording the total mass of solution, and then evaporating off the solvent. The solid left behind is the solute, which is then weighed and used to calculate mass percent. Density can also be used to determine the mass percent of an unknown concentration.

in my opinion:)

Answer:

No matter where that object is in the vast universe, it will have the same mass. Weight, on the other hand, is a measure of how much gravitational force is exerted on an object.

most reactive among them is fluorine because it is the most electronegative element

Answer:

fluorine (F)

Explanation:

I took the test on edge

Answer:Boiling water is a physical change, as it rearranges molecules but does not affect the internal structures. Boiling water forces the water molecules away from each other as the liquid changes to vapor. In a chemical change, new chemical substances are created or formed. Advertisement. Physical changes affect the state of an item, and a chemical change happens at a molecular level.

Explanation:

hope it helps:))

Answer:

gragsgv

Explanation:

cwnbcsjhbvcd

Answer:

halving the volume of a gas

Explanation:

Entropy refers to the degree of disorderliness of a system. The greater the volume of a gas, the greater its entropy. The entropy of a system is directly proportional to its volume.

Hence a decrease in the volume of a gas leads to a decrease in its entropy. Ultimately, if the volume of a given mass of gas is halved, its entropy decreases according.

Answer: [tex]\Delta H_{vap}[/tex] = 55.1 kJ/mol

Explanation: Molar Enthalpy of Vaporization([tex]\Delta H_{vap}[/tex] ) is the energy needed to change 1 mol of a substance from liquid to gas at constant temperature and pressure.

For the 2-hydroxybiphenyl, there two temperatures and 2 pressures. In this case, use Clausius-Clapeyron equation:

[tex]ln\frac{P_{2}}{P_{1}}=\frac{\Delta H_{vap}}{R} (\frac{1}{T_{1}}-\frac{1}{T_{2}} )[/tex]

[tex]\Delta H_{vap}[/tex] is in J/mol:

1) Temperature in K

[tex]T_{1}=[/tex] 286  +273 = 559K

[tex]T_{2}[/tex] = 145 + 273 = 418K

2) Both pressure in Pa

[tex]P_{1}[/tex] = 101325Pa

[tex]P_{2}[/tex] = 14*133 = 1862Pa

Since molar enthalpy is in Joules, gas constant R is 8.3145J/mol.K

Replacing into the equation:

[tex]ln\frac{1862}{101325}}=\frac{\Delta H_{vap}}{8.3145} (\frac{1}{559}-\frac{1}{418} )[/tex]

[tex]ln(0.0184)=\frac{\Delta H_{vap}}{8.3145} (\frac{141}{233662} )[/tex]

[tex]\Delta H_{vap}=\frac{-3.9954*1942782.7}{-141}[/tex]

[tex]\Delta H_{vap}=55051.02[/tex]

[tex]\Delta H_{vap}=55051.02[/tex]

[tex]\Delta H_{vap}=55.1[/tex] kJ/mol

Using those values, molar enthalpy is 55.1 kJ/mol

Comparing to the CRC Handbook, which is [tex]\Delta H_{vap}=71[/tex] kJ/mol:

[tex]\frac{55.1}{71}[/tex] = 0.78

The calculated value is 0.78 times less than the CRC Handbook.

Answer:

They are more spread out.

Explanation:

The atoms and molecules in gases are much more spread out than in solids or liquids. They vibrate and move freely at high speeds. A gas will fill any container, but if the container is not sealed, the gas will escape. Gas can be compressed much more easily than a liquid or solid.

Answer:

Explanation:

Explanation:

Gas – In a gas, particles are in continual straight-line motion. The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely of each other. In most cases, there are essentially no attractive forces between particles

celcius and Fahrenheit are the same at -40 degrees since the scales converge . celcius and Kelvin become Equal at high temperatures as the difference. of 273. 15 between them gets lost in the noise . 0 degree Celsius is Equal to 32degrees Fahrenheit.

Answer:

Specific heat is the amount of heat energy required to raise the temperature of substance by, the units for specific heat is, each element have particular fixed specific heat.

The heat energy change can be obtained by the formula



Temperature change can be represented by 



If we know the specific heat of substance then we can easily calculate the heat energy change of the substance

Answer:

In order of increasing frequency and decreasing wavelength these are: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays........... ᕕ( ᐛ )ᕗ

..

Answer:

dez nuts. the forth quauter in ur girls buttr

Gas is well separated with no regular arrangement, liquids are close together and solids are tightly packed. Solid, liquid, and Gas are the state of substances at room temperature.

There are three state of substances:

The chair you are sitting on is a solid, the water you drink is liquid, and the air you breathe is a gas. The atoms and molecules don't change, but the way they move about does. Water, for example, is always made up of two hydrogen atoms and one oxygen atom.

Physical properties of a particular substance determine its state at room temperature. If both its normal melting point and its normal boiling point are below room temperature (20°C), the substance is a gas under normal conditions.

Oxygen is a gas at room temperature. If the normal melting point of a substance is below room temperature, the substance is a liquid at room temperature.

If both the normal melting point and the normal boiling point are above room temperature, the substance is a solid.

Therefore, solid, liquid and gas all exist as substances at room temperature.

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Explanation:

4hr 30 m = 270 min

270/ 26.1 = 10. 34

1 mile per 10.34 mins

Answer:

c

Explanation:

From the equation, we can say that we need thrice the number of hydrogen than that of nitrogen

we are given 3 moles of nitrogen and 11 moles of hydrogen

but thrice the number of moles of nitrogen is 9, hence we have hydrogen in excess or Hydrogen is the excess reagent

Since we had 11 moles of Hydrogen and we only needed 9, 2 moles of hydrogen are left over

From the equation, we can see that the moles of ammonia formed will be twice the moles of nitrogen

Since 3 moles of nitrogen are used, the reaction will give us 6 moles of Ammonia and NOT 12 moles, therefore c is the correct answer

Since we have hydrogen in excess, our reaction is being limited because we have less Nitrogen, Hence Nitrogen is the Limiting Reagent

Option C is the only false statement

The false statement is that "12.0 moles of ammonia are produced"

According to the equation of reaction:

N₂  +  3H₂  >>>>>  2NH₃

1  mole of N₂ reacts with 3 moles of H₂

3 moles of N₂ will react with 9 moles of H₂

Since 3 moles of N₂ is said to react with 11 moles of H₂ (instead of 9 moles of H₂), H₂ is in excess by 2 moles. That is, N₂ is the limiting reactant.

Since N₂ is the limiting reactant:

1 mole of  N₂ produces 2 moles of NH₃

3 moles of N₂ will produce 6 moles of NH₃

Therefore, we can conclude that:

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Answer:

The answer is

Explanation:

In order to calculate the volume needed we use the formula

[tex]V_2 = \frac{C_1V_1}{C_2} [/tex]

where

C1 is the concentration of the stock solution

V1 is the volume of the stock solution

C2 is the concentration of the diluted solution

V2 is the volume of thevdiluted solution

From the question

C1 = 1.45 M

V1 = 25 mL

C2 = 0.0245 M

So we have

[tex]V_2 = \frac{1.45 \times 25}{0.0245} = \frac{36.25}{0.0245} \\ = 1479.59...[/tex]

We have the final answer as

Hope this helps you

Answer:

C

Explanation:

its not A since its actually the atoms in exactly 12g of crabon-12

-not B since its grams not kilograms

-not D since it says "gram" which would mean that we measure the particles in a gram instead of a mole

Avogadro's number is the number of atoms, molecules, ions, formula units, or other particles in a mole of a substance. Therefore, option (c) is correct.

The Avogadro constant commonly denoted [tex]N_A[/tex] is the proportionality factor that the number of constituent particles such as molecules, atoms, or ions in one mole of a sample.

Avogadro's number is a constant with an exact value of 6.022 × 10²³ reciprocal moles. Avogadro's number is named by Stanislao Cannizzaro after the Italian scientist Amedeo Avogadro, who explained it four years after Avogadro's death.

The numerical value of the Avogadro constant is in reciprocal moles, a dimensionless number known as the Avogadro number. The value of the Avogadro constant, the mass of one mole of a chemical compound, in grams.

It is numerically equal to the average mass of one molecule of the compound in daltons. One dalton is 1/12 of the mass of one carbon-12 atom, which is the mass of one nucleon.

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Answer:

It will melt everything and if lava goes into water it will become rock.

Hope this helped you!

Explanation: