Can someone please help me with this question??

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

We have

[tex]n = \frac{3 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{3}{6.02} \\ = 0.49833...[/tex]

We have the final answer as

Hope this helps you

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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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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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:

40.72g of sulfuric acid are needed

Explanation:

When sulfuric acid, H₂SO₄, is neutralized by lead (IV) hydroxide, Pb(OH)₄, Lead (IV) sulfate, Pb(SO₄)₂ and water as follows:

2 H₂SO₄ + Pb(OH)₄ → Pb(SO₄)₂ + 4H₂O

To solve this question we must find the moles of 57.18g of Pb(SO₄)₂. As 2 moles of H₂SO₄ produce 1mol Pb(SO₄)₂ we can find the moles of H₂SO₄ and its mass as follows:

Moles Pb(SO₄)₂ -Molar mass: 275.23 g/mol-

57.18g * (1mol / 275.23g) = 0.2078 moles Pb(SO₄)₂

Moles H₂SO₄:

0.2078 moles Pb(SO₄)₂ * (2mol H₂SO₄ / 1mol Pb(SO₄)₂) = 0.4155 moles H₂SO₄

Mass H₂SO₄ -Molar mass: 98g/mol-

0.4155 moles H₂SO₄ * (98g / mol) =

Answer: 4 ATP molecules is produced in the glycolysis of 2 glucose molecules

The first stage of most carbohydrate catabolism, which is described as the breakdown of larger molecules into smaller ones, is glycolysis, which is a part of cellular respiration. Two Greek words that mean "to break down anything sweet" are the source of the word glycolysis. Two molecules of ATP are created during the breakdown of glucose and formation of pyruvate during glycolysis.

Explanation:

2 ATP are produced.

For every glucose molecule, meaning that for every 2 glucose molecules, 4 ATP will be created.

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1.trans-[Pt(en)2Cl2]2+  

2.coordination compound Na [Al (OH)] systematic name: sodium tetrahydroxidoaluminate (III)

For several industrial and technical applications, sodium aluminate serves as an efficient supply of aluminum hydroxide. A white crystalline solid with the chemical formula NaAlO2, NaAl(OH)4 (hydrated), [2] Na2OAl2O3, or Na2Al2O4, pure sodium aluminate (anhydrous) is a white substance. Both a solution and a solid form of sodium aluminate are sold commercially.Other comparable compounds, often referred to as sodium aluminate, include Na5AlO4 and Na7Al3O8, which contain complex polymeric anions and Na17Al5O16 and NaAl11O17, which was originally wrongly thought to be -alumina, a phase of aluminum oxide.Aluminum chloride, sodium chloride, and water are produced when hydrogen chloride and sodium tetrahydroxoaluminate interact. Diluted hydrogen chloride in a solution form.

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In the molecule C2H4, valence orbitals of the carbon atoms are assumed to be e) sp^2 hybridized.

The set of orbitals that can energetically accept electrons to create chemical bonds is known as the valence shell. The ns and np orbitals in the outermost electron shell make form the valence shell for main-group elements.

The outside electrons engaged in bonding are called valence electrons. A particular atom can have 0 to 7 valance electrons since valance electrons can only exist in the s and p orbitals. Noble gases are atoms that have no valence electrons and dislike forming bonds.

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answer :

this is the structure if you want it

First, we must compute the index of hydrogen deficiency, IHD, using the molecular formula of the compound [tex]C_{10}H_{14}O_{2}[/tex].

What is a spectrum data?

Spectrum data is data collected from spectroscopic experiments, which measure the interaction of matter with electromagnetic radiation. This data can be used to identify the chemical composition of a sample, as different elements and molecules absorb and emit radiation at different wavelengths.

Then, number of C atoms - [tex]\frac{number of atoms}{2} + 1[/tex]

                                          = [tex]10 + \frac{14}{2} + 1[/tex]

                                          = [tex]10 - 7 + 1[/tex]

                                          = [tex]4[/tex]

Based on the molecular structure, this tells us how many multiple bonds and rings the compound has.

This compound contains four unsaturated bonds. We can tell from the spectrum data that it is aromatic (chemical shifts above 6 comes from aromatic protons). Based on this, we can conclude that the structure of this compound contains a benzene ring. Four IHD are found in the benzene ring, one from the ring and three from double bonds.

Following that, IR spectrum data revealed that absorption on [tex]3150-2850 cm^{-1}[/tex] indicated hybridised CH bonds.

The following chemical shifts are observed in the NMR spectrum data:

On 1,4ppm, it becomes a 6H triplet. It has two protons in its neighbourhood because it is a triplet, and it comes from [tex]CH_{3}(1)[/tex]. This group must be linked to the [tex]CH_{2}(2)[/tex].

A quartet on 4,0ppm, belongs to 4H from [tex]CH_{2}(2)[/tex].  It has 3 protons in neighborhood stop it it attached to the [tex]CH_{3}(1)[/tex] and singlet on 6,8ppm comes of aromatic protons, 4H (3).

Based on the [tex]^{1} HNMR[/tex] spectrum data, we can only attach the two O atoms to the benzene ring and the [tex]CH_{2}(2)[/tex] group.

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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 mass is not a vector.

because It has only magnitude but not direction.

The first mistake that the student made is drawing the start line with ink. So it will run/dissolve in the solvent / split up

The second mistake that the student made is placing the solvent above the spots or start line instead of under them. So they will mix with solvent or wash off paper or color the solvent or dissolve in the solvent.

In the first mistake, there is no clear, visible starting line for the experiment as the ink flows or dissolves in the solvent. This error can lead to confusion and inaccuracy in results as students cannot accurately measure or compare the progress of their experiments.

The second mistake, it mixes or washes away the solvent with the dirt and starts the line, making it difficult or impossible to observe or measure the progress of the experiment. This error can also lead to inaccuracies in results, as students may not be able to accurately measure or compare the progress of their experiments.

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The mathematical expressions written using a single exponent are as follows:

4⁴(4⁷) = 4¹¹

5⁹/5³; a = 6

(6²)⁷ = 6¹⁴

A number or letter written above and to the right of a mathematical expression known as the base is termed an exponent. It denotes that the base is to be increased in strength.

Consider the following expression: xⁿ

In the given expression above, the base is x, while the exponent or power is n. For expressions having the same base, the exponents are added if the expressions are to multiplied, and subtracted when the expressions are to be divided.

The exponents are multiplied if the exponents are raised to a power.

Considering the given expressions:

4⁴(4⁷) = 4¹¹

5⁹/5³ =  5⁶

Hence, a = 6

(6²)⁷ = 6¹⁴

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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.

MassMass of oxygen used on combustion of 0.554 mol of phosphorus is 957.12 g.

Combustion is the name given to the chemical reaction in which a material combines with oxygen to produce heat. A substance is said to be combustible if it can burn. Another name for it is fuel. Fuel can be either solid, liquid, or gaseous.

Since, 4 moles of phosphorus burns in the presence of 5 moles of oxygen

Therefore, 0.554 moles of phosphorus will burn in presence of 54×0.554=29.91 moles of oxygen.

Molar mass of oxygen is 32 g/mol.

Hence, mass of oxygen used can be calculated by:

Mass of oxygen used under given reaction conditions =32×29.91⇒957.12 g.

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Mass of oxygen used on combustion of 0.554 mol of phosphorus is 957.12 g. Oxygen has an atomic mass of 15.9994. ss.

Combustion is the name given to the chemical reaction in which a material combines with oxygen to produce heat. Another name for it is fuel. Fuel can be either solid, liquid, or gaseous.

4 moles of phosphorus burns in the presence of 5 moles of oxygen 0.554 moles of phosphorus will burn in presence of 54×0.554=29.91 moles of oxygen. Molar mass of oxygen is 32 g/mol. Mass of oxygen used under given reaction conditions 32×29.9 = 957.12 g.

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Answer:

1.5 moles

Explanation:

The equation of the reaction is given as:

2 MnO2 + 4 KOH + O2 --> 2KMnO 4 + 2KOH + H2

From the equation,

2 moles of MnO2 produces 2 moles of KMnO4

x moles of MnO2 would produce 1.5 moles of KMnO4

2 = 2

x = 1.5

Solving for x;

x = 1.5 * 2 / 2

x = 1.5 moles

Answer:

Na----1

N-----1

O-----3

H-----3

3+3+1+1 =8

There are 8 atoms in that compound.

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:

Energy transfer between the particles in solids, liquids, and gases can explain how warm matter outside a cup can cause a cold liquid inside the cup to warm up.

Explanation:

Answer:

The drink in the regular cup warms up.

Explanation:

The reason why it warms up is because the cup is colder than room temperature and melts another reason why the drink in the regular cup warms up is because when we breathe out hot air is coming out soo that also makes the drink warmer.

Answer:

0.89 times

Explanation:

Let the initial volume of the tank be V.

Finally, we shall determine how much larger the final volume of the gas will be. This is illustrated below:

Initial pressure (P₁) = 130 kPa

Initial volume (V₁) = V

Final pressure (P₂) = 145.5 kPa

Final volume (V₂) =?

P₁V₁ = P₂V₂

130 × V = 145.5 × V₂

130V = 145.5 × V₂

Divide both side by 145.5

V₂ = 130V / 145.5

V₂ = 0.89V

Therefore, the final volume of gas will be 0.89 times the initial volume.

Answer:

Specific heat capacity of iron (c) = -0.04 J/g°C

Explanation:

Given:

Mass of sample of iron M = 716.4 gram

Change in temperature Δt = -33.47°C

Heat energy Q = 996.6 joules

Find:

Specific heat capacity of iron (c)

Computation:

We know that

Q = McΔt

So,

c = Q / M[Δt]

Specific heat capacity of iron (c) = 996.6 / (716.4)(-33.47)

Specific heat capacity of iron (c) = 996.6 / -23,977.908

Specific heat capacity of iron (c) = -0.0415

Specific heat capacity of iron (c) = -0.04 J/g°C

Answer:

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:

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.

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:

Mg + 2HCl=== Mg(Cl)2 + H2

The Reaction is a single displacement reaction.

Yes!

This reaction obeys the law of conservation which states that for a closed system... Matter and energy transfer is constant.

Meaning that the Mass of products must equal mass of Reactants

To prove this

lets Calculate the Mass of reactants

24g + 73g=97g.

Mass of Products...

95g + x.

let's calculate the mass of Hydrogen produced.

Note: You can get it using any of the reactants... I'll use Magnesium

Now from the balanced reaction.... 1mole of Mg reacts to produce 1mole of Hydrogen

Moles of Mg=Mass/Molar Mass

Given Mass=24g

Molar mass of Mg=24

Mole of Mg =24/24

=1mole

Since Mole ratio of Mg and H2 is 1:1.... Therefore 1Mole of Hydrogen is produced too.

To get Mass of H2

Again

Mole=Mass/Mm

Known= 1mole of H2 isproduced

Mass of H2 =2g

Mole=Mass/Mm

Mass =Mole x Mm

= 1 x 2

=2g

Now

Total Mass of products is

95 +2 = 97g.

This is the same with the Mass of Reactants

So The Law of Conservation of Mass Holds.

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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Answer:

Chemical Compound

Explanation:

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