pls help me i really need help

Answer:

50 g of S are needed

Explanation:

To star this, we begin from the reaction:

S(s) + O₂ (g) →  SO₂ (g)

If we burn 1 mol of sulfur with 1 mol of oxygen, we can produce 1 mol of sulfur dioxide. In conclussion, ratio is 1:1.

According to stoichiometry, we can determine the moles of sulfur dioxide produced.

100 g. 1mol / 64.06g = 1.56 moles

This 1.56 moles were orginated by the same amount of S, according to stoichiometry.

Let's convert the moles to mass

1.56 mol . 32.06g / mol = 50 g

Answer:

the answer p+n

Explanation:

91.2 g Mn

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

[Given] 1.00 × 10²⁴ atoms Mn

Step 2: Identify Conversions

Avogadro's Numer

[PT] Molar Mass of Mn - 54.94 g/mol

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

91.2321 g Mn ≈ 91.2 g Mn

Answer:

the scientific definition of work

Explanation:

In physics, work is defined as the use of force to move an object. For work to be done, the force must be applied in the same direction that the object moves.

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Answer: The molar mass of menthol is 156.15 g/mol

Explanation:

Depression in freezing point is given by:

[tex]\Delta T_f=K_f\times m[/tex]

[tex]\Delta T_f=T_f^0-T_f=2.84^0C[/tex] = Depression in freezing point

[tex]K_f[/tex] = freezing point constant = [tex]20.8^0C/m[/tex]

m= molality

[tex]\Delta T_f=K_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}[/tex]

Weight of solvent (cyclohexane)= 25.0 g = 0.025 kg  

Molar mass of solute (menthol) = ?

Mass of solute (menthol) = 0.533 g

[tex]2.84^0C=20.8\times \frac{0.533}{xg/mol\times 0.025}[/tex]

[tex]x=156.15g/mol[/tex]

The molar mass of menthol is 156.15 g/mol

The given question is incomplete. The complete question is:

The standard heat of combustion is shown in the following chemical equation [tex]C_9H_{20}(g)+14O_2(g)\rightarrow 9CO_2(g)+10H_2O[/tex][tex]\Delta H_{rxn}=-6125.21kJ/mol[/tex].  If 130 g of nonane combusts , how much heat is released?

Answer: 6211.21 kJ

Explanation:

Heat of combustion is the amount of heat released on complete combustion of 1 mole of substance.

Given :

Amount of heat released on combustion of 1 mole of nonane = 6125.21 kJ

According to avogadro's law, 1 mole of every substance occupies 22.4 L at NTP, weighs equal to the molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

1 mole of nonane [tex](C_9H_{20})[/tex] weighs = 128.2 g  

Thus we can say:  

128.2 g of nonane on combustion releases = 6125.21 kJ

Thus 130 g of [tex]C_4H_{10}[/tex] on combustion releases =[tex]\frac{6125.21}{128.2}\times 130=6211.21kJ[/tex]

Thus the heat of combustion of 130 g of nonane is 6211.21 kJ

Answer:

Explanation:

mass fraction N₂ : He : CH₄ : C₂H₆ : : 15 : 5 : 60 : 20

mole fraction  N₂ : He : CH₄ : C₂H₆ : : 15/28 : 5/4 : 60/16 : 20/30

mole fraction  N₂ : He : CH₄ : C₂H₆ : : .5357  : 1.25 : 3.75 : .67

Total mole fractions = .5357 + 1.25 + 3.75 + 0.67 = 6.2057

mole fraction of N₂ =  .5357 / 6.2057 = .0877

mole fraction of He = 1.25 / 6.2057 = .20

mole fraction of CH₄ = 3.75 / 6.2057 = .6043

mole fraction of C₂H₆ = .67 / 6.2057 = .108

Partial pressure = total pressure x mole fraction

Partial pressure of N₂ = 1200 kPa  x .0877 = 105.24 kPa

Partial pressure of He = 1200 kPa  x .20  = 240 kPa

Partial pressure of CH₄ = 1200 kPa  x  .6043  = 725.16 kPa

Partial pressure of C₂H₆ = 1200 kPa  x .108    = 129.6 kPa

Answer:

2.68 cm^3

Explanation:

Density= Mass/Volume

so...

8.96 g/cm^3 = 24.01 g/ V

and then u solve so it would be 2.68 cm ^3

((:

This question is incomplete, the complete question is;

A reaction that proceeds by first-order irreversible kinetics is oxidizing chemical A in a wastewater treatment basin with a mean residence time of 1.5 hours. The reaction rate constant is 2.0 Hr-1.The basin is unbaffled and may be characterized as two completely mixed tanks in series.  If the steady-state influent concentration is 30 mg/l, find the effluent concentration.

If baffles are placed in the basin so that the basin may be characterized as four completely mixed tanks in series, and the mean residence time remains constant, find the effluent concentration.

Answer:

a) (two completely mixed tanks in series) the find the effluent concentration is 4.8 [tex]\frac{mg}{l}[/tex]

b) (four completely mixed tanks in series) find the effluent concentration is 3.2 [tex]\frac{mg}{l}[/tex]

Explanation:

Given the data in the question;

we can determine the effluent concentration of two completely mixed tanks in series for first order irreversible reaction using the following equation;

C = Co ( 1 / ( 1 + K[tex]\frac{t}{n}[/tex] )ⁿ

t is the mean hydraulic residence time for two completely mixed tanks in series ( 1.5 hr)

Co is initial concentration of the influent ( 30 [tex]\frac{mg}{l}[/tex] )

C is final concentration of effluent,

n is the number of tanks series ( 2)

k is rate constant for the given first order reaction( 2[tex]\frac{1}{hour}[/tex] )

so we substitute

C = 30 [tex]\frac{mg}{l}[/tex]  ( 1 / ( 1 + 2[tex]\frac{1}{hour}[/tex] . [tex]\frac{1.5}{2}[/tex] )²

C = 30 [tex]\frac{mg}{l}[/tex]  × ( 1/2.5)²

C = 30 [tex]\frac{mg}{l}[/tex] × 0.16

C = 4.8 [tex]\frac{mg}{l}[/tex]

Therefore, (two completely mixed tanks in series) the find the effluent concentration is 4.8 [tex]\frac{mg}{l}[/tex]

b)

using;

C = Co ( 1 / ( 1 + K[tex]\frac{t}{n}[/tex] )ⁿ

t is the mean hydraulic residence time for two completely mixed tanks in series ( 1.5 hr)

Co is initial concentration of the influent ( 30 [tex]\frac{mg}{l}[/tex] )

C is final concentration of effluent,

n is the number of tanks series ( 4)

k is rate constant for the given first order reaction( 2[tex]\frac{1}{hour}[/tex] )

so we substitute

C = 30 [tex]\frac{mg}{l}[/tex]  ( 1 / ( 1 + 2[tex]\frac{1}{hour}[/tex] . [tex]\frac{1.5}{4}[/tex] )⁴

C = 30 [tex]\frac{mg}{l}[/tex] × ( 1/1.75)²

C = 30 [tex]\frac{mg}{l}[/tex] × 0.107

C = 3.2 [tex]\frac{mg}{l}[/tex]

Therefore, (four completely mixed tanks in series) find the effluent concentration is 3.2 [tex]\frac{mg}{l}[/tex]

Answer: Octane will be used completely.

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of octane}=\frac{2.3g}{114g/mol}=0.0202moles[/tex]

[tex]\text{Moles of oxygen}=\frac{12.4g}{32g/mol}=0.388moles[/tex]

The balanced chemical reaction will be

[tex]2C_8H_{18}+25O_2(g)\rightarrow 16CO_2(g)+18H_2O(g)[/tex]  

According to stoichiometry :

2 moles of octane require = 25 moles of [tex]O_2[/tex]

Thus 0.0202 moles of octane will require=[tex]\frac{25}{2}\times 0.0202=0.2525moles[/tex]  of [tex]O_2[/tex]

Thus octane is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.  

Thus octane will be used completely.

The boiling point of water generally increases as the amount of impurities (which a solute like KCl technically can be thought of) dissolved increases. This relation can be quantified using the equation,

[tex]\Delta T_b = i \times K_b \times m[/tex]

where [tex]\Delta{T}_{b}[/tex] is the change in the water's boiling point (normally taken to be 100 °C), [tex]i[/tex] is the Van 't Hoff factor (the number of particles a single formula unit of the solute dissociates into in water), [tex]K_b[/tex] is the boiling point elevation constant, and [tex]m[/tex] is the molality (moles of solute/kilogram(s) of solvent) of the solution.

We are forming a solution by dissolving KCl in water. KCl is an electrolyte that, in water, will dissociate into K⁺ and Cl⁻ ions. So, for every formula unit, KCl, we obtain two particles. Thus, the Van 't Hoff factor, or [tex]i[/tex], will be 2.

The molality of the solution can be calculated by dividing the number of moles of KCl by the mass of water in kilograms. Since we have 1.00 kg of water, we would be dividing 0.75 mol KCl by 1, giving us a molality (m) of 0.75 m.

We aren't provided the boiling point elevation constant for water. Several authoritative sources give the value 0.512 °C/m, so we will adopt that as our [tex]K_b[/tex].

Note: m = mol/kg as used in this problem.

Plugging everything in,

[tex]\Delta T_b = i \times K_b \times m \\\Delta T_b = 2 \times 0.512 \text{ } \frac{^oC}{mol/kg} \times 0.75 \text{ } \frac{mol}{kg} \\\Delta T_b = 0.768 \text{ } \mathrm{ ^oC}[/tex]

As you can see, our change in boiling point is positive (the boiling point is elevated), and it is also quite modest. Taking 100 °C to be the boiling point of pure water, the boiling point of our solution would be 100 ⁰C + 0.768 ⁰C, or 100.768 ⁰C.

If we are considering significant figures, then we must give our answer to two significant figures (since 0.75 has two sig figs). We can regard the boiling point of water (100 ⁰C) as a defined value. Since our final answer is a sum, the boiling point of our solution to two significant figures would be 100.77 ⁰C.

Given:

We know,

The molality of the solution will be:

= [tex]\frac{Mole}{Mass}[/tex]

= [tex]\frac{0.75}{1}[/tex]

= [tex]0.75 \ m[/tex]

Now,

→ [tex]T_{solution}-T_{water} = Kb\times m\times i[/tex]

By putting the values, we get

                              [tex]= 0.51\times 0.75\times 2[/tex]

                              [tex]= 0.765[/tex]

hence,

Solution's boiling point will be:

→ [tex]T_{solution} = 100+0.765[/tex]

                [tex]= 100.765^{\circ} C[/tex]

Thus the above approach is right.

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Answer:

5.80200 Kg / L

Explanation:

[tex]\tt -\dfrac{1}{2}\dfrac{d[N_2O]}{dt}=\dfrac{1}{2}\dfrac{d[N_2]}{dt}=\dfrac{1}{1}\dfrac{d[O_2]}{dt}[/tex]

Reaction

2N2O(g) — 2N2(g) + O2(g)

Required

relative rate

Solution

The reaction rate (v) shows the change in the concentration of the substance (changes in addition to concentrations for reaction products or changes in concentration reduction for reactants) per unit time.

so the relative rates for the reaction above are :

[tex]\tt -\dfrac{1}{2}\dfrac{d[N_2O]}{dt}=\dfrac{1}{2}\dfrac{d[N_2]}{dt}=\dfrac{1}{1}\dfrac{d[O_2]}{dt}[/tex]

Answer:

d. Mass is the measure of the earth’s gravitational attraction of a body

This is FALSE. Mass is the measure of matter than an object contains.

Explanation:

b. An atom is the smallest particle of an element that still contains properties of the original element.

This is True

c. Gases can be colorless or colored

This is True

d. Mass is the measure of the earth’s gravitational attraction of a body

This is FALSE. Mass is the measure of matter than an object contains.

e. A pure substance has a fixed composition.

This is True.

Answer:

C8H16O4

Explanation:

C2H4O= 24+4+16

44

n=molar mass/empirical formula

n=176.21/44

=4

Therefore

Molar Formula= (C2H4O)4=C8H16O4

Answer: B) Electronegativity is the attraction an element's nucleus has for the electrons in a chemical bond

Explanation:

Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself.

When the size of an atom decreases as we move across the period, as the electrons get added to the same shell and the nuclear charge keeps on increasing. Thus the electrons get more tightly held by the nucleus.

As, the size of an element decreases, the valence electrons come near to the nucleus. So, the attraction between the nucleus and the shared pair of electrons increases and thus the electronegativity increases.

Answer:

D) There are 33 particles inside of the nucleus and 16 particles outside of the nucleus.​

Explanation:

Sulfur has an atomic number of 16. The atomic number represents the number of protons, so sulfur has 16 protons.

This atom of sulfur has a mass number of 33. The mass number is the sum of protons and neutrons. Then, the number of neutrons is 33 - 16 = 17

Sulfur is a neutral atom. Therefore, it has the same number of positive charges (protons) and negative charges (electrons). Thus, sulfur has 16 electrons.

Protons and neutrons are in the nucleus and electrons are outside the nucleus.

Taking all the above into account, the correct answer is:

D) There are 33 particles inside of the nucleus and 16 particles outside of the nucleus.​

Answer:

D) There are 33 particles inside of the nucleus and 16 particles outside of the nucleus.​

Explanation:

Sulfur has an atomic number of 16. The atomic number represents the number of protons, so sulfur has 16 protons.

This atom of sulfur has a mass number of 33. The mass number is the sum of protons and neutrons. Then, the number of neutrons is 33 - 16 = 17

Sulfur is a neutral atom. Therefore, it has the same number of positive charges (protons) and negative charges (electrons). Thus, sulfur has 16 electrons.

Protons and neutrons are in the nucleus and electrons are outside the nucleus.

Taking all the above into account, the correct answer is:

D) There are 33 particles inside of the nucleus and 16 particles outside of the nucleus.​

Answer:

The conditions are

1) Small enough

2) Electronegative atom

3) highly electronegative

4) lone pair of electrons

The correct statement therefore is

It needs to be small enough not to bump into other atoms when approaching the 1s orbital of the hydrogen, it needs to carry at least one electronegative atom, it needs to be highly electronegative enough to create a delta on the connected hydrogen, and it needs to have at least one lone pair of electrons.

Explanation:

Hydrogen bonding is a type of intermolecular bond that occurs between the partial positive charge (delta) on a hydrogen atom bonded to a small highly electronegative element (like nitrogen, oxygen or fluorine) and the free electrons on another electronegative element of another molecule.

The hydrogen atom with the partial positive charge (delta) is known as the hydrogen bond donor, while the electronegative element, carrying lone electrons is called the hydrogen bond acceptor.

Let's take a deeper look at these terms:

1) Hydrogen bond donor

Using water (H₂O) as an example, the high electronegativity of the oxygen atom covalently bonded to the hydrogen atom draws the lone electron in the 1s orbital of the hydrogen atom, creating a partial positive charge (d⁺) on the hydrogen atom. This is what happens within one water molecule

2) Hydrogen bond acceptor

When two or more molecules of water interact, the partial positive charge (d⁺) on the hydrogen atom of one molecule, is attracted to the valence or free electrons on the oxygen atom of a nearby molecule of water thus creating a dipole-dipole intermolecular bond known as a hydrogen bond.

For the hydrogen bond to be effective, the electronegative atom bonded to the hydrogen acting as the hydrogen bond donor in the first water molecule needs to be small enough so as not to disrupt the 1s orbital of the hydrogen atom. The smaller the size of the electronegative atom, the stronger the partial negative charge created on the hydrogen atom.

The valence or free pair of electrons on the electronegative (oxygen) atom of the second molecule of water (hydrogen bond acceptor) is what attracts the partial positive charge on the hydrogen atom to create the hydrogen bond

Answer:

298. 7 K.

Explanation:

Hello!

In this case, since equation we use to compute the heat in a cooling or heating process is:

[tex]Q=mC(T_f-T_i)[/tex]

Whereas we are given the heat, mass, specific heat and initial temperature. Thus, we infer that we need to solve for the final temperature just as shown below:

[tex]T_f=T_i+\frac{Q}{mC}\\\\T_f=1000 K+\frac{-270000J}{1000g*0.385\frac{J}{g*K} } \\\\T_f=298.7 K[/tex]

It is important to notice that the iron release heat as water absorbs it, that is why it is taken negative.

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Answer:

[tex]\frac{3}{2}He[/tex]

[tex]\frac{6}{2} He[/tex]

[tex]\frac{7}{4}Be[/tex]

[tex]\frac{3}{1} H[/tex]

[tex]\frac{6}{4}Be[/tex]

[tex]\frac{7}{3} Li[/tex]

Explanation:

In the first nucleus we are told that there are two protons and one neutron. Let us remember that the mass number = number of protons + number of neutrons.

This implies that, for the first specie the mass number is 3, for the second specie the mass number is 6 and the third specie has a mass number of 7 and so on. The mass number is indicated as a superscript.

The atomic number is the number of protons in the nucleus of the atom and helps us to identify the atom. It is always written as a subscript as shown.

Answer: i think its A diatomic compound..

Explanation: hope i helped! sorry if im wrong!

Answer:

Explanation:

Measurement made = 100.2 °C

uncertainty = 0.1°C

percent uncertainty = .1 x 100 / 100.2

= .099 %

2 nd thermometer :

Measurement made = 99.0 °C

uncertainty = 0.5°C

percent uncertainty = .5 x 100 / 99

= .505  %

Percent error :

1 st thermometer

Error = 100.2 - 100 = .2 °C

measurement = 100.2

percent error = .2 x 100 / 100.2

= .1996 %

2 nd thermometer

Error = 100.00 - 99 = 1.00 °C

measurement = 99

percent error = 1 x 100 / 99

= 1.01  %

Percent uncertainty is the measure of degree of error region with the  uncertainty in the measurement.

The percentage error is the difference in the measurement of the values with actual value.

The percent uncertainty (%U) is calculated by:

[tex]\% U=\rm \dfrac{Uncertainty}{Measurement}\;\times\;100[/tex]

The percent error (%E)  is calculated by:

[tex]\%E=\rm \dfrac{error\;value-actual\;value}{error\;value}\;\times\;100[/tex]

The Recorded temperature = 100.2 degree Celsius

The actual temperature = 100 degrees Celsius

The uncertainty in the readings is 0.1 degree Celsius

The percent uncertainty is given by:

[tex]\%U=\dfrac{0.1}{100.2}\;\times\;100\\\\ \%U=0.099\;\%[/tex]

The percent uncertainty of digital thermometer is 0.099 %.

The percent error is given by:

[tex]\% E=\dfrac{100.2-100}{100.2}\;\times\;100 \\\\\% E=\dfrac{0.2}{100.2}\;\times\;100\\\\ \% E=0.1996\;\%[/tex]

The percent error of digital thermometer is 0.1996 %.

The Recorded temperature = 99 degree Celsius

The actual temperature = 100 degrees Celsius

The uncertainty in the readings is 0.5 degree Celsius

The percent uncertainty is given by:

[tex]\%U=\dfrac{0.5}{99}\;\times\;100\\\\ \%U=0.505\;\%[/tex]

The percent uncertainty of analog thermometer is 0.505%.

The percent error is given by:

[tex]\% E=\dfrac{100-99}{99}\;\times\;100 \\\\\% E=\dfrac{1}{99}\;\times\;100\\\\ \% E=1.01\;\%[/tex]

The percent error of analog thermometer is 1.01 %.

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Answer:

2914 J

Explanation:

Step 1: Given data

Step 2: Calculate the temperature change

ΔT = 27.09 °C - 15.71 °C = 11.38 °C

Step 3: Calculate the energy required (Q)

We will use the following expression.

Q = c × m × ΔT

Q = 0.3850 J/g.°C × 665.0 g × 11.38 °C

Q = 2914 J

Answer: The mowed lawn is the one from where the grasses are removed by using the machines or tools.

Explanation:

The mowed lawn is expected to have low number of species as the grasses may be few or scanty thus can support the population of few species like insects, mice, birds, and small number of grazing animals. On the other hand the weedy field can be hub of insects, reptiles like snakes, small mammals, and large mammals. Large weed field can provide food, and habitat to the large number of species. This will support the increase in biodiversity as compared to the mowed lawn.

Answer:

Dispersion forces

Dipole-Dipole interaction

Explanation:

The London dispersion force refers to the temporary attractive force that acts between the electrons in two adjacent atoms when the atoms develop temporary dipoles. Dispersion forces act between any two molecules even when other intermolecular forces are in operation as long as the molecules are in close proximity to each other.

Now, CO is polar and the HCN is also polar molecule. Hence, dipole - dipole interaction forces  are also in operation and acts between the two molecules in close proximity to each other.

Dispersion forces and Dipole-Dipole interaction are intermolecular forces which act between a hydrogen cyanide (HCN) molecule and a carbon monoxide molecule

The transitory attractive force that exists between the electrons in two nearby atoms when the atoms form transient dipoles is known as the London dispersion force. As long as the molecules are close to one another, dispersion forces can exist between any two molecules, even when other intermolecular forces are active.

The HCN molecule and CO are both polar molecules right now. As a result, dipole-dipole interaction forces act between the two molecules when they are close to one another.

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