a chemist employed by an airplane manufacturer investigates new adhesives for the purpose of building airplanes without rivets. she is engaged in group of answer choices risk-benefit analysis. alchemy. applied research. basic research.

Answer:

Below

Explanation:

First , note that TWICE as many moles of O2 are required as CH4

  so ya need to figure out the number of moles in 12.54 g of CH4

From periodic table find weights of C and H

C = 12.011     H = 1.008  g / mole

  so a mole of CH4   is    12.011 + 4 * 1.008 = 16.043 g / mole

now  12. 54 g / 16.043 g/mole  = .78 mole of CH4

    remember from above, you need twice as many moles of O2

           .78 x 2 = 1.56 moles of O2

The balanced equations are given below:

1. 2 Cu₂O + C ---> 4 Cu + CO₂

2. 2 H₂O₂ ---> 2 H₂O + O₂

3. 2 AI + Fe₃N₂ ---> 2 AlN + 3 Fe

4. 8 Ag₂S --> 16 Ag + S₈

5. 3 ZnS + 2 AIP ---> Zn₃P₂ + Al₂S₃

6. 2 Fe(OH)₃ ---> Fe₂O₃ + 3 H₂O

A chemical equation that is balanced has equal amounts of each element's atoms on both sides of the equation and conserves mass.

An element is balanced if it has the same amount of atoms on both sides of the equation. The equation is balanced if all the moles of atoms of component elements are equal on both sides of the equation.

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0.800 moles of CO2 are produced when 0.400 moles of glucose are used in the fermentation reaction.

The number of moles of CO2 produced when 0.400 moles of glucose (C6H12O6) are used can be calculated from the balanced chemical equation for the reaction. According to the equation, for every 1 mole of glucose that reacts, 2 moles of CO2 are produced:

C6H12O6 -> 2C2H5OH + 2CO2

Therefore, when 0.400 moles of glucose are used, the number of moles of CO2 produced can be calculated as follows:

0.400 moles of glucose * 2 moles of CO2 per 1 mole of glucose = 0.800 moles of CO2

So, 0.800 moles of CO2 are produced when 0.400 moles of glucose are used in the fermentation reaction.

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At 0.752 atm of H2S and 1073 K, [H2] = 4.94 x 10^-12 mol/L and [S2] = 4.24 x 10^-5 mol/L. At 0.20 atm of H2 and 0.40 atm of S2, [H2] = 1.67 x 10^-12 mol/L and [S2] = 4.68 x 10^-5 mol/L.

The reaction for the decomposition of hydrogen disulfide (HS) is:

2 H2S (g) <=> 2 H2 (g) + S2 (g)

The equilibrium constant (Kc) at 1073 K is 2.0 x 10^-23.

1) At the initial conditions of 0.752 atm of H2S and the temperature of 1073 K, the equilibrium concentrations can be calculated using the equation:

Kc = [H2]^2 / [S2].

Rearranging the equation to solve for [H2], we get:

[H2]^2 = Kc * [S2]

[H2] = sqrt(Kc * [S2])

Since the initial pressure of H2S is 0.752 atm, we can convert it to concentration using the ideal gas law:

P = nRT/V, where n = number of moles, R = gas constant (8.31 J/mol*K), T = temperature (1073 K), and V = volume.

Since n = PV/RT, [H2S] = P/RT.

[H2S] = 0.752 atm / (8.31 J/mol*K * 1073 K) = 8.48 x 10^-5 mol/L.

[S2] = [H2S] / 2 = 4.24 x 10^-5 mol/L.

[H2] = sqrt(2.0 x 10^-23 * 4.24 x 10^-5) = 4.94 x 10^-12 mol/L.

2) At the new initial conditions of 0.20 atm of H2 and 0.40 atm of S2, the new equilibrium concentrations can be calculated using the Kc expression:

Kc = [H2]^2 / [S2].

[H2] = sqrt(Kc * [S2]) = sqrt(2.0 x 10^-23 * (0.40 atm / (8.31 J/molK * 1073 K))) = 1.67 x 10^-12 mol/L.

[S2] = 0.40 atm / (8.31 J/molK * 1073 K) = 4.68 x 10^-5 mol/L.

These are the new equilibrium concentrations at the new initial pressures and temperatures.

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The complete Question is:

Consider the reaction for the decomposition of hydrogen disulfide:         2H2S W=23 H2 = S2t Ko-2. Ax10 at 1073 K. A reaction vessel initially contains 0.752 atm of H2S at 1073K. Find the equilibrium concentrations of H2 and S2. The reaction in question 2 is then carried out at the same temperature but the initial pressures were 0.20 atm for H2 and 0.40 atm for S2. Calculate the equilibrium concentrations.

The theoretical yield of the reaction is 65.7 grams.

Mass C₆H₆ = 45.6 g

actual yield = 63.7 g

Balanced chemical formula:

C6H6 (l) + Cl2 (g) → C6H5Cl (s) + HCl (g)

Calculate the molar masses of C6H6 and C6H5Cl.

For C₆H₆

Molar mass of C₆H₆ = (12.01 g/mol × 6) + (1.008 g/mol × 6)

Molar mass of C₆H₆ = 78.108 g/mol

For C₆H₅Cl

Molar mass of C₆H₅Cl = (12.01 g/mol × 6) + (1.008 g/mol × 5) + (35.45 g/mol × 1)

Molar mass of C₆H₅Cl = 112.55 g/mol

Since 1 mole of C6H6 = 1 mole of C6H5Cl, the theoretical yield of the reaction is

65.7 grams

Yield calculation = 96.9%

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The average translational kinetic energy for a single molecule of SO3(g) at 416 K is approximately 0.864 x 10^-20 J.

The average translational kinetic energy of an ideal gas molecule can be calculated using the equation:

KE = (3/2)kT

where KE is the average translational kinetic energy, k is the Boltzmann constant (1.38 x 10^-23 J/K), and T is the temperature in Kelvin.

Given that the temperature of SO3(g) is 416 K, the average translational kinetic energy can be calculated as follows:

KE = (3/2)k * 416 K = (3/2) * (1.38 x 10^-23 J/K) * 416 K

KE = (3/2) * (1.38 x 10^-23 J/K) * 416 K

KE = (3/2) * (0.576 x 10^-20 J)

KE = 0.864 x 10^-20 J

So, the average translational kinetic energy for a single molecule of SO3(g) at 416 K is approximately 0.864 x 10^-20 J.

The units of this result are joules, which are the standard units of energy.

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A tire has a pressure of 325 kPa at 10°C, the new pressure of tire is 285 Pka by using formula P1T1 = P2T2

Initial pressure = 325 kPa

Initial temperature = 10°C

Final temperature = 50°C

As given that the volume is constant.

Now, P1T1 = P2T2

P2 = P1T1 / T2

P2 = 325 kPa x 10 + 273 K / 50 + 273 K

P2 = 285 Pka

Thus, a tire has a pressure of 325 kPa at 10°C, the new pressure of tire is 285 Pka.

What is pressure?

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The given relative mass formula is correct. The weight in grams of the number of atoms of an element contained in 12.00 g of carbon-12 is known as the relative atomic mass of the element.

The ratio of an element's average atomic mass to the unified atomic mass unit is the relative atomic mass, or Ar. The average mass of an element's isotopes is used to calculate the relative atomic mass.

Absolute mass is the total mass of all protons and neutrons, whereas relative mass is the average atomic mass of all the isotopes present in a given percentage. As an illustration, the average atomic mass of carbon, calculated using the proportions of the isotopes C-12, C-13, and C-14, is 12.01 while the absolute mass of carbon is 12.0 amu.

An element's mass number is determined by the sum of its proton and neutron counts: Protons and neutrons together make up mass.

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Answer: These confrontations of different air masses are called frontal boundaries. A cold front occurs when a colder air mass comes in contact with a warmer air mass. A violent change in weather occurs as the cold air mass digs underneath the warm air mass creating thunderstorms and snowstorms in the winter.

yes very nice

In the given chemical equation, oxidation takes place at anode  of the electrochemical cell .

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

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The resulting ΔS will be the entropy change in the process of converting 3 kg of ice at -5°C to water at 92°C.

The entropy change in the process can be calculated using the equation ΔS = ΔH/T, where ΔH is the change in enthalpy and T is the temperature.

In this process, the ice at -5°C is being converted to water at 92°C. The change in enthalpy, ΔH, is equal to the latent heat of fusion, Lf, plus the change in enthalpy of the water from -5°C to 92°C. This can be calculated using the equation ΔH = 3 kg * Lf + 3 kg * 4.18 J/g°C * (92°C - (-5°C)).

The entropy change, ΔS, can then be calculated using the equation ΔS = ΔH/T, where T is the temperature of the water, 92°C. The resulting ΔS will be the entropy change in the process of converting 3 kg of ice at -5°C to water at 92°C.

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Heating a cup of tea before adding a spoonful of sugar would increase solubility. Therefore, the correct option is option D.

Solubility in chemistry refers to a material's capacity to create a solution with that other substance, the solvent. The incapacity of the solute to produce such a solution is referred to as insolubility.

The concentration of a solute inside a saturated solution, where no more solute could be dissolved, is used to determine the extent of a substance's solubility in a certain solvent. The two compounds are considered to be in solubility equilibrium at this moment. Heating a cup of tea before adding a spoonful of sugar would increase solubility.

Therefore, the correct option is option D.

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The new pressure of the oxygen in the container is approximately 8.74 atm.

According to the Ideal gas Law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in kelvins. We can use this equation to solve for the new pressure, as long as we know the other variables.

First, we need to find the number of moles of oxygen in 300 cm³. We can use the ideal gas law to convert cm³ to liters and find the number of moles:

V = 300 cm³ = 0.3 L

R = 8.31 J/ mol·K

T = (273 + 20) K = 293 K (room temperature)

n = PV / RT = (10 × 0.3) / (8.31 × 293) = 0.001054 moles

Next, we need to find the new volume of the oxygen, given the container size. We can convert the 5.0 dm² container to cm² and find the volume:

V_container = 5.0 dm² × 10⁴cm²/dm² = 5.0 × 10⁴ cm³

V_new = V_container - V = 5.0 × 10⁴ - 0.3 = 49999.7 cm³

Finally, we can use the ideal gas law to find the new pressure:

P_new = (nRT) / V_new = (0.001054 × 8.31 × 293) / (49999.7 / 10³) = 8.74 atm

So, the new pressure of the oxygen in the container is approximately 8.74 atm.

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Electrons are transferred from one atom to the other during ionic bonding. Among the given compounds, FeCl₃ is an ionic compound in which three electrons are transferred from Fe atom each chlorine.

Ionic compounds are formed between metals and non metals. Metals are electro rich and easily loss one or more electron from their valence shell. Nonmetals are mostly electronegative and will gain electrons to achieve octet.

Amon the given compounds all are covalent covalent compounds except  FeCl₃. In ferric chloride, Fe is in +3 oxidation state and losses three electrons each for three chlorine atoms.

Cl contains 7 valence electrons and it need one more electron to achieve octet. Hence, each Cl gains one electron from the Fe metal. Hence, option 4 is correct.

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The freezing point of pure solvent is -4.14 °C.

Since urea in solution neither associate nor dissociate so, i = 1

The molar mass of urea = 60.06 g/mol

Given mass of urea added = 9.350 g

⇒ moles of urea = mass / molar mass

= 9.350 / 60.06

=0.1557 mol

Mass of solvent X = 150.0 g = 0.150 kg

⇒ Molality of urea, m = moles / mass of solvent

= 0.1557 / 0.150

= 1.0379 mol.kg-1

Given Kf = 1.89 °C.kg.mol-1

By depression in freezing point formula-

ΔTf = Kf × m × i

Substituting the values we get,

ΔTf = 1.89 °C.kg.mol-1 × 1.0379 mol.kg-1 × 1

ΔTf = 1.96 °C

Since ΔTf = (T f Of Pure Solvent) - (T f Of Solution)

T f Of Solution = -6.1 °C

⇒ ΔTf = (T f Of Pure Solvent) - (T f Of Solution)

⇒ 1.96 °C = (T f Of Pure Solvent) - (-6.1 °C)

⇒ T f Of Pure Solvent = (1.96 - 6.1)°C

⇒ T f Of Pure Solvent = -4.14 °C

Hence, the freezing point of pure solvent is -4.14 °C.

The given question is incomplete and the complete question is given as,

The Molal Freezing Point Depression Constant Kf = = 1.89 °C • Kg: Mol For A Certain Substance X. When 9.350 G Of Urea dissolved in 150 g of X , the solution freezes at -6.1° C. calculate the freezing point of pure solvent X.

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The value x in the chemical symbol is Aluminium.Aluminum (or aluminium in British English) is a chemical element with the symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, and ductile metal that is widely used in various industries for its light weight, high strength, and good conductivity properties. Aluminum is the third most abundant element in the Earth's crust, after oxygen and silicon, and is found in many minerals including bauxite.

The chemical symbol for aluminum is "Al". The number of electrons and neutrons in an atom does not determine the chemical symbol for that element. The chemical symbol for an element is based on its atomic number, which is the number of protons in the nucleus of an atom of that element. The atomic number of aluminum is 13, so its chemical symbol is always "Al".

Some common uses of aluminum include the manufacture of transportation vehicles, packaging materials, construction materials, electrical conductors, and consumer goods. It is also used in the aerospace, defense, and high-tech industries due to its high strength-to-weight ratio and good thermal conductivity.

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N₂ (78.1% of air) could be that gas.

What is gas?

Gas is a form of matter that has no fixed shape or volume. It is made up of molecules that are in constant motion and are spread out in all directions, taking up the space available. Gas molecules usually have low density and are highly compressible, meaning that they can be compressed into a smaller space than their original volume. Gases can be composed of many different elements or compounds, including oxygen, nitrogen, carbon dioxide, and methane. Gas molecules are affected by temperature, pressure, and the amount of gravity present. When these factors are changed, the gas molecules react accordingly.

Therefore, N₂ (78.1% of air) could be that gas.

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To make 100 ml of 50 mM Tris-HCl buffer at pH 7.4 in a lab, you can follow these steps:

Measure out the desired amount of Tris base stock solution, which has a concentration of 0.5 M. For 100 ml of 50 mM Tris-HCl buffer, you will need 50 mM / 0.5 M = 0.1 moles of Tris base.

Transfer the calculated amount of Tris base to a suitable container and add distilled water to make up the desired volume (100 ml in this case).

Adjust the pH of the solution to 7.4 using a suitable buffer such as HCl or NaOH. To do this, you can add a small amount of the acid or base at a time and measure the pH until you reach the desired value of 7.4.

Stir the solution until it reaches homogeneity and the pH is stable. You can measure the pH again to confirm that it is 7.4.

Store the Tris-HCl buffer at room temperature in a suitable container until it is ready to be used.

It is important to note that the pH of the buffer should be checked and adjusted if necessary before use, as pH drift may occur over time.

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The NMR signal at 2.10 ppm is more deshielded, meaning it is more chemically shift shifted to a higher field compared to the signal at 1.15 ppm. That is due to protons that are closer to electronegative atoms.

In the 1H NMR spectrum of a product, the chemical shift of the signals provides information about the environments of the protons in the molecule. The signal at 2.10 ppm is more deshielded compared to the signal at 1.15 ppm, meaning that it is shifted to a higher field. This indicates that the protons responsible for the signal at 2.10 ppm are closer to electronegative atoms or are experiencing a strong inductive effect, leading to greater electron density around the nucleus and hence a more deshielded signal. On the other hand, the signal at 1.15 ppm is due to protons that are further away from electronegative atoms or experiencing weaker inductive effects, resulting in less electron density around the nucleus and a less deshielded signal. Understanding the chemical shifts in 1H NMR spectra requires knowledge of the molecular structure and the environments of the protons in the molecule.

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Answer:

approx. 5.0 x10^24 atoms

Explanation:

The molar mass of water is 18.02g/mol

50 grams of water contains 50g x 1 mole/18.02g moles of water

2.775 moles H2O

1 mole of H2O contains 6.022 x 10^23 molecules of water

2.775 moles of H2O contains 2.775 x 6.022 x 10^23 molecules of H2O

= 1.6711 x 10^24 molecules of H2O

1 molecule of H2O contains 3 atoms

Therefore 1.6711 x 10^24 molecules contains 1.6711 x 10^24 x 3 atoms

= approx. 5.0 x10^24 atoms

Answer:

answer is one

Explanation:

valency is the amount of electrons on the last shell

92% percentage of the iceberg was under water.

The percentage of an iceberg that is under water can be calculated by finding the ratio of the submerged portion of the iceberg to its total volume, and converting this ratio to a percentage. To do this, we need to know the density of the ice and water and the densities of both materials.

If the density of water is 1.0 g/cm3 and the density of ice is 0.92 g/cm3, then the iceberg will float in water. The portion of the iceberg that is above water will have a volume equal to the difference in the volumes of the water displaced and the portion of the iceberg that is above water.

Let V be the volume of the iceberg, and Vw be the volume of water displaced. Then, the portion of the iceberg that is above water will have a volume of V - Vw. The portion of the iceberg that is below water will have a volume of Vw. The percentage of the iceberg that is under water is given by:

Density of water = 1g/cm^3

Density of Ice = 0.921g/cm^3

ρ(ice)V(ice) = ρ(water)V(water)

so, V(water) =(ρ(ice)V(water))/ ρ(water)

or, V(water) = 0.92V(water)/1.0

V(water) = 0.92V(ice)

So, 92% percentage of the iceberg was under water.

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2.55 moles of aluminum hydroxide in grams is 198.9grams.

The number of moles can be converted to mass using the following expression:

mass = number of moles × molar mass

According to this question, 2.55 moles are present in aluminium hydroxide. It can be converted to mass as follows:

Molar mass of aluminum hydroxide = 78g/mol

Mass = 78g/mol × 2.55 mol

mass = 198.9grams

Hence, 198.9grams is the mass present in 2.55 moles of aluminum hydroxide.

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The statement that is true about the carbon is the correct option is d) it can form both polar and nonpolar bonds.

The atomic number of the carbon is 6. The carbon can form the nonpolar covalent bonds when the carbon bonds to itself, like as in graphene and the diamond. The carbon forms the polar covalent bonds with the elements that have the  slightly more electronegativity. The example of the polar bon is the carbon and the oxygen bond is the polar covalent bond.

Thus, the carbon can form the polar bond as well it can form the non polar bond.

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Answer:

The chemical formula of Tetraoxosilicate(IV) acid is H4SiO4

High insulation resistance, high dielectric strength, low dielectric constant, low dielectric loss at all frequencies, strong resistance to cold flow, and exceptional abrasion resistance are only a few of the outstanding electrical qualities.

On telephone signal and control cables, high frequency electronic cables, high and low voltage power cables, line wire, neutral supported secondary, and service drop cable, polyethylene is frequently used as insulation.

In comparison to polyethylene resins, polypropylene is less dense. This polymer's chemical, electrical, and electrical characteristics are comparable to those of polyethylenes. Its fluid resistance is a little higher. It has a somewhat lower dielectric constant than LDPE.

Compared to polyethylene, polypropylene is significantly stiffer and tougher. Additionally, its elasticity at low temperatures is not great. If antioxidants are not present, heat and light can cause it to deteriorate.

Therefore, High insulation resistance, high dielectric strength, low dielectric constant, low dielectric loss at all frequencies, strong resistance to cold flow, and exceptional abrasion resistance are only a few of the outstanding electrical qualities.

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We think that our dependency is primarily on non-renewable energy sources because these resources are required and important for our daily lives.

We depend on non-renewable energy for example fossil fuels resource because of the reason that they are energy-rich and comparatively cheap to process. But a big problem with fossil fuels resource, apart from them being in limited supply, is that burning them releases carbon dioxide into the atmosphere.

We think today that humanity's use of fossil fuels resource is damaging our environment. Fossil fuels resource which is non-renewable energy cause pollution where they are produced and used, and their continuous use is causing long-term harm to the climate of our planet.

So we can conclude that our dependence on nonrenewable energy sources makes sense because our lives depend on them.

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The bonding model for sodium metal and sodium chloride are fundamentally different, reflecting the differences between metallic and ionic bonds. The metallic bond in sodium metal is characterized by free electrons, while the ionic bond in sodium chloride is characterized by the strong electrostatic forces between positive and negative ions.

Sodium (Na) is a metal, and its bonding model is based on the metallic bond. In a metallic bond, the valence electrons are not bound to any one individual atom, but instead are free to move through the entire metallic lattice, resulting in a highly conductive, solid material. The metallic bond is held together by electrostatic attraction between the positively charged metal ions and the negatively charged electrons.

On the other hand, sodium chloride (NaCl) is an ionic compound, and its bonding model is based on the ionic bond. In an ionic bond, electrons are transferred from one atom to another atom, resulting in the formation of ions. The positive and negative ions are held together by strong electrostatic forces.

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Reaction of 7.5 g of sodium carbonate with a dilute solution of hydrochloric acid (HCl) gives a mass of 8.28 g of NaCl.

1 mole of sodium carbonate yields 2 moles of sodium chloride.

To find grams and volume, we need to calculate the molecular mass of the reactants and products.

So the molecular mass will be:

Na2Co3=106

2 NaCl = 117

160 g Na2Co3 = 117 g NaCl (1)

7.5 g Na2Co3 gives = 'X' g NaCl (2)

Cross-multiplying equations 1 and 2 gives:

X × 106 = 117 × 7.5

X = 8.28

Diploma:

From this we conclude that 7.5 g of sodium carbonate reacts with a dilute solution of hydrochloric acid (HCl) to yield 8.28 g of mass NaCl.

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