please help with this question

The empirical and molecular formula of benzene is CH and C6H6 that contains only carbon and hydrogen and the mass of hydrogen is 7.74%.

Molar mass of benzene is = 78.1%

Hydrogen = 7.44%

We have to find empirical and molecular formula

We calculate the percentage of Carbon in the compound is as follow:

Percentage of compound = 100%

Hydrogen = 7.44%

We have find the percentage of carbon

Carbon = (Percentage of compound) - (Hydrogen)

= 100-7.44

= 92.56%

Calculate empirical formula:

Carbon (C) = 92.56%  Hydrogen (H) = 7.44% Empirical formula = ?

Firstly, divide by their molar mass

C = 92.56 / 12 = 7.71, H = 7.44 / 1 = 7.44

Divide by the smallest

C = 7.71 / 7.74 = 1, H = 7.44 / 7.44 = 1

Empirical formula of benzene = CH

Calculate Molecular formula

Molecular mass of benzene = 78.1 g / mol. Empirical formula = CH, Molecular formula = ?

Molecular formula = Empirical formula  X n

Molecular formula = molar mass

Therefore, Empirical formula x n = molar mass

[CH]n = 78.1, [12 + 1]n = 78.1,

13n = 78.1

Divide both sides by 13

n = 78.1 / 13

n = 6

Molecular formula = C6H6

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Answer:

the entry of harmful foreign particles into the atmosphere is known as pollution there are 7 main types of pollution namely air ,water,light ,sound, thermal , radioactive,land pollution.we can reduce sound pollution by making green zones around schools and hospitals

Answer:

n = 12.18 moles

Explanation:

Given that,

The volume of a canister, V = 1 L

The temperature of the canister, T = 100 K

Pressure, P = 100 atm

We need to find the number of moles of gas. Let there are n number of moles. We know that,

PV = nRT

Where

R is gas constant, R = 0.0821 L*atm/mol*K

[tex]n=\dfrac{PV}{RT}\\\\n=\dfrac{100\times 1}{0.0821 \times 100}\\\\n=12.18\ moles[/tex]

Hence, there are 12.18 moles of gas.

Answer: B:Light moves in a straight line except at surfaces between different transparent materials, where its path bends.

Explanation:

The equivalent point's pH is 3.60.

A numerical measure of how acidic or basic aqueous or other liquid solutions are is called pH, and  The expression, which is widely used in chemistry, biology, and agronomy, translates the hydrogen ion concentration, which normally ranges between 1 and gram-equivalents per liter, into values between 0 and 14. Since pure water has a pH of 7, or gram-equivalents per liter of hydrogen ions, it is neutral (neither acidic nor alkaline). An alkaline or basic solution has a pH over 7, whereas one with a pH below 7 is described as acidic.

HNO2 = 0.100M

KOH= 0.200M

pKa = 3.34

using a formula

pH = pKa + log (salt/acid)

= 3.34 + log (0.200/0.100)

= 3.34 + log 2

= 3.34 + 0.30

= 3.60

The equivalent point's pH is 3.60.

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Answer:

The correct answer is (C) 0.2 mole MgCl2

Explanation:

Answer:

answer is here bit.^{}ly/3gVQKw3

Answer:

To calculate the percent of copper in copper oxide, you would need to know the mass of copper in the compound and the mass of the compound itself. Once you have this information, you would divide the mass of copper by the mass of the compound and multiply by 100 to express the result as a percentage.

Example:

If the mass of copper in copper oxide is 40 grams and the mass of the compound is 100 grams, the percent of copper in the compound would be:

(40/100) * 100 = 40%

It should be noticed that this is an example, I don't have access to the chemical analysis of your copper oxide.

Explanation:

In order to produce a nucleotide, the combinations 11, 12, and 13 may be combined.

The basic unit of DNA and RNA are nucleotides. Genetic material is present in them. Since many biological reactions involving enzymes require coenzymes, nucleotides serve in this capacity. ATP serves as the body's energy storage system.

A phosphodiester bond forms when the 5' phosphate group of one nucleotide and the 3'-OH group of another nucleotide come together during the incorporation of nucleotides into DNA (see below). Phosphate-sugar-phosphate-sugar-phosphate forms the "backbone" of each DNA strand in this way.

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Answer:

Acidic

Explanation:

the pH scale ranges from 0 to 14, where 7 means the substance is neutral. Less than 7 means the substance is Acidic. Greater than 7 means the substance is Basic.

Remember that the lower the pH is, the more Acidic the substance is. In this case lemon juice is Acidic.

The relationship between properties and substances is an important one as the properties define or describe the type, kind or composition of a substance. There are two factors that affect the properties of a substance and these are kinetic energies and intermolecular forces.

In chemistry, substances are categorized on the basis of physical and chemical properties. All the substances are composed of tiny particles which are in constant motion due to kinetic energy and keep moving in all directions in a substance.

In addition to this, intermolecular forces are also present in a substance which keeps the particles together. In this way substances maintain their shape, arrangement and properties such as melting point, boiling point, hardness, composition and color due to their particular properties.

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Answer:

HCl acts as an excess reagent

Explanation:

The reaction equation is;

PbO + 2HCl → PbCl2 + H20

Number of moles of PbO = 13g/223.2 g/mol = 0.058 moles

Since the mole ratio is 1:1, 0.058 moles of PbCl2 is produced

Number of moles of HCl = 6.4 g/36.5g/mol = 0.175 moles

2 moles of HCl yields 1 mole of PbCl2

0.175 moles yields 0.175 moles * 1/2

= 0.0875 moles of PbCl2

Hence; PbO yields the least number of moles of product so it is the limiting reactant and HCl is the reactant in excess

The reactivity of the metals as we go across in the period or  from the left to the right horizontally in the periodic table it will decreases.

The reactivity of the metals as we move across the period from left to right in the periodic table it will decreases. the reactivity of the metals as we move in the group from top to the bottom in the periodic table it will increases due the increase in the size of the elements from top to bottom.

Thus, the reactivity of the metals decreases as we move across period from left to the right in the periodic table.

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When Br2(l) boils at its normal boiling point, its entropy increases as it is positive.

The level of randomness found inside a substance's molecules is known as entropy.

The temperature at which atmospheric pressure and a liquid's vapor pressure are equal is known as the boiling point.

The amount of heat energy required to convert one mole of a substance from its liquid state into its gaseous state at constant temperature and pressure is referred to as the molar enthalpy of vaporization.

Entropy increases when a liquid is heated because the randomness between the molecules increases. As a result, entropy will rise.

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The element with electronic configuration 2s1, which is lithium, has a violent reaction with cold water.

The most reactive metals in the periodic table are the alkali metals (Li, Na, K, Rb, Cs, and Fr); they all react with cold water violently or even explosively, displacing hydrogen. In the reduction of water to hydrogen gas (H2) and the metal ion hydroxide (OH), Group 1 Metal (M) is oxidised to its metal ions.

The second most reactive metals in the periodic table are the alkaline earth metals (Be, Mg, Ca, Sr, Ba, and Ra), which also exhibit increased reactivity in higher periods like the Group 1 metals. The only alkaline earth metal that does not react with water or steam, even when heated to a high temperature, is beryllium (Be).  Furthermore, beryllium has an exterior oxide layer that is robust, which reduces its reactivity at lower temperatures.

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Since lead has a density of 11.53 g/cm^3, the volume of a 0.255 pound sample of lead is equal to 10.03 cm³.

In Science, the density of a chemical substance such as lead can be calculated by using this formula:

Density = M/V

Where:

Next, we would convert the value of the mass in pound to grams by multiplying it by 453.6 as follows;

Mass = 0.255 × 453.6

Mass = 115.668 grams

Making volume the subject of formula, we have:

Volume = Mass/Density

Volume = 115.668/11.53

Volume = 10.03 cm³.

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Answer:

the answer is d which is soap solution because it's a soap solution that can measure the degree of hardness of a water if the water forms with this soap solution then the water is hard but if the water forms foam with soap then it is soft

Answer:

soap solution because when it is combined with water you can get to your answer and that it is right or experiment it

Answer:

sp3d

Explanation:

The ground state electronic configuration of tin is; [Kr] 5s²4d¹⁰5p². Hybridization is a valence bond concept that postulates that orbitals of appropriate energy could be mixed in order to produce suitable orbitals that could be used for bonding.

In the formation of Snf5^ -1, there is a hybridization of the 5p, 5d and 6s orbitals to yield the sp3d orbitals required for the formation of the chemical specie hence the answer.

Answer:

Chemical Compound

Explanation:

I'm not sure why but I know it's chemical. Hope this helps!

Federal Marshals will receive trafficking penalty for attempting smuggling.

Human trafficking, also referred to as trafficking in persons, is a crime that entails forcing or coercing a person to perform work or services or engage in sexual acts for monetary gain. The exertion of pressure may be covert or obvious, physical or psychological.

A conviction for keeping someone in servitude carries potential fines and a maximum 20-year prison sentence in a federal facility. The maximum penalty is life in prison if there is a death as a result of the violation or if it involved kidnapping, sexual assault, or other aggravating circumstances.

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Propanol, because its molecules can form hydrogen bonds with water molecules.

Reason:

Therefore, propanol is more soluble in water than Ethane.

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Answer:

5.45*10⁻⁴ moles of silane gas (SiH₄) are present in 8.68 mL  measured at 18°C and 1.50 atm.

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case:

Replacing:

1.5 atm* 0.00868 L= n* 0.082[tex]\frac{atm*L}{mol*K}[/tex] *291 K

Solving:

[tex]n=\frac{1.5 atm*0.00868 L}{0.082 \frac{atm*L}{mol*K}*291 K}[/tex]

n= 5.45*10⁻⁴ moles

5.45*10⁻⁴ moles of silane gas (SiH₄) are present in 8.68 mL  measured at 18°C and 1.50 atm.

Answer:

c

Explanation:

valence is the number of electrons in the outer most she'll.. therefore all elements in the same group have the same valences for example group one elements have a valence of one

I hope this helps

Answer:

Atomic orbital

Explanation:

Electrons are found around the atomic nucleus in three-dimensional regions.

The energy levels they are in can be named according to a numbering order such as 1, 2, 3, 4, ..., increasing in proportion to the distance to the nucleus. Each of these energy levels can be divided into sublevels s, p, d, f which are also called orbitals.

1.53 × 10⁻⁵ moles of aspartame are present in 4.50 mg of aspartame.

Two amino acids, aspartic acid and phenylalanine, make up the low-calorie sweetener known as aspartame. In addition to being present in tabletop sweetener packets, aspartame is a common component used to substitute sugar in low-calorie foods and beverages.

Here there are 4.50 mg of aspartame.

First, the mass is converted from mg to g by:

1 g = 1000 mg

So, 1 mg = 0.001 g

So, 4.5 mg = 4.5 × 10⁻³ g

Molar mass of aspartame = 294.40 g/mol

So, Number of moles of aspartame = [tex]\frac{Given mass}{Molar mass}[/tex]

or, n = 4.5 × 10⁻³ / 294.3

or, n = 1.53 × 10⁻⁵ moles.

Hence, 4.50 mg of aspartame has 1.53 × 10⁻⁵ moles of aspartame.

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Ice will not melt as we need 16.72 KJ of heat but we have only 3.76 KJ

In thermodynamics, the enthalpy of fusion can be described as the change in its enthalpy resulting from giving energy, heat, to a specific amount to change its state from a solid to a liquid.

Given the reaction is  2 Na (s) + 2 H₂O(l) → 2 NaOH (aq) + H₂ (g)

Given the mass of sodium = 0.470 g

The moles of sodium = 0.470/23 = 0.020 mol

Given that two moles of sodium (Na) release heat = 368 KJ

Heat released by 0.020 mol of sodium (Na) = (368/2) × 0.020 = 3.76 KJ

Given the mass of ice = 50g

The number of moles = 50/18 = 2.78 mol

For melting, one mole of ice heat is required = 6.02 kJ/mol.

For 2.77 mol of ice = 6.02 × 2.78 = 16.72 KJ

But we have only 3.76 KJ of heat therefore, the ice will not melt.

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Atoms are basically the smallest units of matter. They are made up of  protons, neutrons and electrons.

The periodic table is a tabular arrangement of the chemical elements which are organized on the basis of their atomic numbers, electron configurations, and recurring chemical properties. The periodic table lists the elements in order of increasing atomic number and grouped into rows (periods) and columns (groups). The elements in the same column have similar chemical properties, with the elements in the same row having similar outer electron configurations.

Atom X: Number of protons = 6

Atom Y: Number of protons = 6

b. Atoms X and Atom Y are in the same family; but not the same row; in the periodic table.

Hence, Option B is correct.

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The question is:

Question 3 (5 points) (02.06 MC) The table compares some characteristics of two atoms_ Charged Particles Atom Number 0f Neutrons Mass Number] Use the table t0 determine the number of protons for each atom: Then_ choose the statement below that Is true about the two atoms_ points) Atom X and Atom are in the same row; but not the same family; on the periodic table Atoms X and Atom Y are in the same family; but not the same row; in the periodic table; Atom Xis in a column to the right of Atom Y in the periodic table: Atom X and Atom occupy the same position in the periodic table because they are isotopes.

Physical characteristics known as size dependant properties alter as an object's size does. Examples of qualities that depend on size include length, width, height, volume, and mass.

The amount or size of the material affects several physical properties of matter, including length, mass, volume, weight, and so forth. These characteristics of matter and their values change together with the size or quantity of the substance.

In physics, mass is a way to measure inertia, a fundamental property of all matter. In actuality, it is the resistance a body of matter provides to a change in its speed or location.

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Answer:

it is option no B using mole concept

Answer:

The correct answer is 77.0 g.