The enthalpy change for the oxidation of styrene, C8H8, is measured by calorimetry.

C8H8 (l) + 10 O2 (g) --> 8 CO2 (g) + 4 H2O (l) :
Hrxn = -4395.0 kJ



Use this value, along with the standard enthalpies of formation of CO2 (g) and H2O (l), to calculate the enthalpy of formation of styrene, in kJ/mol.

Answer:

Earthquakes are measured using instruments called seismometers, that detect the vibrations caused by seismic waves as they travel through the crust. Also, laser beams can be used

Explanation:

The speed of an electron expelled from a surface when light with a wavelength of 690.0 nm is delivered. A wavelength of 795 nm has sufficient energy to eject electrons is v = 2.886 × 10⁵ m/s.

The wavelength, which will also apply to troughs, is the separation between two wave crests. The frequency is measured in cycles per second (Hz), which is the quantity of vibrations that cross a specific area in a second (Hertz). In this article, the relationship between wavelength and frequency is covered.

hf = Φ + KE

Φ = Work function is energy required to remove an electron in (J)

h = Planck’s constant = 6.626 x 10⁻³⁴ J • s

f = threshold frequency or higher

KE = maximum kinetic energy of emitted electrons (J)

Electron mass is 9.109 x 10⁻³¹ kg kg and the speed of light is 2.998 x 10⁸ m/s

The energy of a photon of 795 nm light will give the work function Φ.

λ = 795 nm = 7.95 x 10⁻⁹ m

E = (hc/λ) = 2.499 x 10⁻¹⁹ J

Find the energy of a photon with wavelength λ = 336.0 nm = 3.360 x 10⁻⁷ m

m = 9.1 * 10⁻³¹ kg

1/2mv² = hc (1/690×10⁻⁹ - 1/795 × 10⁻⁹)

1/2mv² = 6.62 × 10⁻³⁴ × 2.998 ×10⁸ (10⁹/690 - 0.001258 × 10⁹⁹)

1/2mv² = 19.874 × 10⁻²⁶ (0.001449 × 10⁻⁹ - 0.001258 × 10⁻⁹)

1/2mv² = 19.847 × 10⁻²⁶ (1.44 * 10⁻⁶ - 1.258 × 10⁶)

1/2mv² = 19.847 × 10⁻²⁰ (1.449 - 1.258)

1/2mv² = 19.847 × 10⁻²⁰ × 0.191

1/2mv² = 3.791 × 10⁻²⁰

v² = 3.791 × 10⁻²⁰/m

v² = 7.582 × 10⁻²⁰/9.1 × 10⁻³¹

v² = 0.8332 × 10¹¹

v² = √8.332 × 10¹⁰

v = 2.886 × 10⁵ m/s.

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The answers are A. Pseudoscience is often based only on opinions; D. Pseudoscience often involves explanations of beliefs; E. Pseudoscience includes subjective ideas.

Explanation:

Pseudosciences comprises disciplines or theories that do not follow scientific standards but claim to be factual. This includes areas such as clairvoyance or astrology because this is not based on evidence but subjectivity. Indeed, the base of most pseudosciences are personal beliefs, opinions, or subjective ideas. Moreover, complex theories or methods are created to try to explain these beliefs, but because they do not follow scientific standards they are not considered as valid. In this context, options A, D, and E are correct.

Answer:

0.8 L

Explanation:

The volume of the stock solution needed to make 2.0 L of 0.20M MgSO4 is 0.8 L.

If an equation includes 7(CrO₄)₂, the numbers of Cr's and O's atoms that are there are 14 and 56 respectively.

The number of atoms present in a chemical compound can be calculated by multiplying the subscript of the particular element by any coefficient.

According to this question, 7 moles of chromate with the chemical formula; (CrO₄)₂ is given. The number of oxygen and chromium atoms in this compound can be calculated as follows:

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The required tubular length for 99.9% conversion is 116.84 meters.

On Earth, the rate at which cyclohexane reacts with benzene and methylcyclopentane is constrained by high mass transfer.

A tubular reactor with an internal diameter of 5 cm and a length of 20 m will be used to conduct the reaction, and cylindrical pellets with dimensions of 0.5 cm in diameter and 0.5 cm in length will be placed within the reactor's pipes.

Only the exterior surface of the pellets are coated.

The packed bed has a 40% porosity and a 60 dm3/min intake flow rate.

When the intake gas stream includes 5% cyclohexane and 95% hydrogen at 2 atm and 500°C, the tubular length vs. conversion graph should be drawn.

The graph may be used to identify the minimum length of tube necessary for 99.9% conversion.

For cyclohexane diffusion in hydrogen, the Fuller, Schettler, and Giddings Correlation is as follows:

a = 0.8854,

b = 1.764102,

C = 6.0231023.

The tube length vs. conversion graph may be displayed at 2 atm and 500°C when the incoming gas stream includes 5% cyclohexane and 95% hydrogen.

The following equation may be used to determine the rate of reaction:

ra=2.31011 exp[-88580/RT]C_A(1X)/3

The mole balancing equation for an isothermal tubular reactor is given as

dX/dL = -ra/C A,

where X is the conversion and L is the length.

To determine the length of the tubular reactor needed for a specific conversion X, we can integrate the aforementioned equation from X = 0 to X = X.

We must numerically calculate the following equation to obtain the necessary tube length for 99.9% conversion:

∫0.999L0−ra/CA 

dL=0.999XEq L 

for X=0.999

After rearranging the equation above, we get:

0.999L0ra/CA

dL=XX Eq

The aforementioned equation is integrated to give us

L = 116.84 m.

Therefore, the required tubular length for 99.9% conversion is 116.84 meters.

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Answer:

(A) getting study help, and retaking classes or exams

(A) applying for a loan

(C) getting study help, and retaking the exam

Explanation:

Answer:

A. The reaction shifts to the right (products) and the concentrations of I and H₂ decrease.

Explanation:

If gas is removed from the system at equilibrium, the system will try to compensate for the loss by shifting the reaction in a direction that produces more gas molecules. This is known as Le Chatelier's principle, which states that a system at equilibrium will respond to a disturbance by shifting in a way that minimizes the effect of the disturbance.

In this case, since gas is being removed from the system, the reaction will shift to the side that produces more gas molecules. Looking at the balanced equation, we can see that 2HI(g) has a greater number of gas molecules compared to H₂(g) and I₂(g). Therefore, the system will shift to the right (products) to produce more HI(g) and reestablish equilibrium.

Answer:

No

It's called a formula of an element which is a sodium element.

Answer:

b, c, e

Explanation:

Inorganic compounds usually lack carbon.

Inorganic compounds are not associated with or made from living things.

Inorganic compounds include salt and water​.

Answer:

yes the answer id bce

Explanation:

Considering the Charles' law, the initial temperature of a balloon is 25°C or 298 K and final temperature is 596 K or 323 °C.

Charles' law establishes the relationship between the temperature and the volume of a gas when the pressure is constant and expresses that the volume is directly proportional to the temperature of the gas: If the temperature increases, the volume of the gas increases while if the temperature of the gas decreases, the volume decreases.

Mathematically, Charles' law states that if the amount of gas and the pressure remain constant, the ratio between the volume and the temperature always has the same value:

V÷T= k

where:

Being 1 an initial state and 2 a final state, it is fulfilled:

V₁÷T₁= V₂÷T₂

In this case, you know:

Replacing in the definition of Charles' law:

2.3 L÷ 298 K= 4.6 L÷T₂

Solving:

(2.3 L÷ 298 K)×T₂= 4.6 L

T₂= 4.6 L÷ (2.3 L÷ 298 K)

T₂= 596 K= 323 °C

Finally, the final temperature is 596 K or 323 °C.

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Answer:

Mass and volume. Density increases with increase in mass. Density decreases with increase in volume.

Based on the given reactions, the compounds are as follows:

A: The specific product formed from the reaction between prop-1-yne and either 2HBr or H2O2.

B: The product formed when compound A reacts with 2H2O.

C: The product formed when compound B reacts with K2CO3(aq).

D: The product formed from the heat-induced reaction of compound C.

E: The product formed when compound D reacts with HBr.

Based on the given reactions, let's analyze the compounds involved:

Reaction 1: prop-1-yne + 2HBr/H2O2 = A

The reactant prop-1-yne reacts with either 2HBr or H2O2 to form compound A. The specific product formed will depend on the reaction conditions.

Reaction 2: A + 2H2O = B

Compound A reacts with 2H2O (water) to form compound B.

Reaction 3: B + K2CO3(aq) = C

Compound B reacts with K2CO3(aq) (potassium carbonate dissolved in water) to form compound C.

Reaction 4: C + heat = D

Compound C undergoes a heat-induced reaction to form compound D.

Reaction 5: D + HBr = E

Compound D reacts with HBr (hydrobromic acid) to form compound E.

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Explanation:

When balancing a chemical equation, the number of elements on the left hand side of the equation must be equal tot he number elements on the right hand side of the equation.

Answer:

31.7 g of water formation in the given reaction releases 783.02 kJ of heat energy.

The change in heat in the given equation is -890.8 kJ/mol. This means that when one mole of CH4 reacts with 2 moles of O2, it produces one mole of CO2 and 2 moles of H2O while releasing 890.8 kJ of heat energy.Now, we have to find out how much heat energy will be released when 31.7 g of water is formed. To do this, we need to first calculate the number of moles of water formed from 31.7 g of H2O.Molar mass of H2O = 2 × 1.008 + 15.999 = 18.015 g/molNumber of moles of H2O = 31.7 g / 18.015 g/mol = 1.759 molNow we know that 2 moles of H2O are formed when 1 mole of CH4 reacts. Therefore, the number of moles of CH4 required to produce 1.759 mol of H2O will be:1 mole of CH4 : 2 moles of H2Ox moles of CH4 : 1.759 moles of H2Ox = 1.759/2 = 0.8795 molSo, 0.8795 moles of CH4 are required to produce 1.759 moles of H2O. And the heat released during the reaction of 0.8795 mol CH4 can be calculated using the given change in heat.ΔH = -890.8 kJ/molHeat released during the reaction of 0.8795 mol CH4= ΔH × number of moles= -890.8 kJ/mol × 0.8795 mol= -783.02 kJ.

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The correct statement from the given option is as follows : Check and see if anyone else can use the chemical. If not, discard in the proper waste container.

A student removes the chemical sample from the reagent bottle to used in an experiment. He should do with any excess chemical that is remaining from that sample after the experiment is complete is he should Check and see if anyone else can use the chemical. If not, discard in the proper waste container.

The remaining chemical can not return to the bottle because , if the student return the this leftover sample, than it can contaminate the entire sample store in the container.

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79942.6 calorie is the number of calories of energy absorbed by the water. The energy of an isolated system holds that energy could be transformed.

In physics, energy is indeed the quantitative quality that is imparted to a body or a physical system and is visible in the form of light and heat.

The energy of an isolated system holds that energy could be transformed in form but cannot be generated or destroyed. The joule is the International System of Units (SI) unit of measurement for energy (J).

Q = 2 kg × 4181 J / kg °C × 40°C

   = 334,480 J

   =79942.6 calorie

Therefore, 79942.6 calorie is the number of calories of energy absorbed by the water.

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Answer:

O2

Explanation:

Diatomic molecules are molecules that have 2 of either H,N,F,O,I,Cl, or Br. In this case, 2H is not correct because the 2 is in front of the element name. Diatomic molecules will have the two after which means that the molecule has these two elements together.

The number of moles of gas produced from the reaction of 2.00g of potassium with an excess amount of water is 0.025 moles.

The reaction of potassium with an excess amount of water is:

2K + 2H\(_2\)O \(\rightarrow\) 2KOH + H\(_2\)

To calculate the moles of hydrogen gas first we need to calculate moles of potassium in 2.00g

No. of moles = (mass) / (molecular mass)

The mass given is 2.00 g and the Molecular mass is 39.09 units

∴ No. of moles = (2) / (39.09) = 0.05

From the above reaction, we get that 2 moles of potassium give 1 mole of hydrogen gas. Thus, 0.05 moles of potassium gives 0.025 moles of hydrogen gas.

Therefore, the no. of moles of hydrogen gas produced is 0.025 moles.

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Answer:

15g

Explanation:

hope this helped

The frequency of the radiation is equal to \(7.17 \times 10^{19}\) Hertz.

Given the following data:

To find the frequency of this radiation, we would use the Planck-Einstein equation.

Mathematically, the Planck-Einstein relation is given by the formula:

\(E = hf\)

Where:

Substituting the given parameters into the formula, we have;

\(4.75 \times 10^{-14} = 6.626 \times 10^{-34} \times F\\\\F = \frac{4.75 \times 10^{-14}}{6.626 \times 10^{-34}}\)

Frequency, F = \(7.17 \times 10^{19}\) Hertz

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Answer:

hope it's help you dear

Explanation:

If one drops a stone into a pond, a very rapid, thin jet of water spouts upwards. ... A cavity forms behind the object during impact on the water surface. This cavity is subsequently compressed by hydrostatic pressure, which leads to the formation of the jet

The machine exerts a force of 9 newtons on the baseball to accelerate it from 0 m/s to 30 m/s in 0.5 seconds.

To calculate the force exerted by the machine on the baseball, we can use Newton's second law of motion, which states that force (F) is equal to the product of mass (m) and acceleration (a).

In this case, the acceleration can be determined using the formula a = (v - u) / t, where v is the final velocity, u is the initial velocity, and t is the time taken for the acceleration.

Given:

Mass of the baseball (m) = 0.15 kg

Initial velocity (u) = 0 m/s (as the baseball starts from rest)

Final velocity (v) = 30 m/s

Time (t) = 0.5 s

First, let's calculate the acceleration:

a = (v - u) / t

a = (30 m/s - 0 m/s) / 0.5 s

a = 60 m/s^2

Now, we can use the calculated acceleration and the given mass to determine the force:

F = m * a

F = 0.15 kg * 60 m/s^2

F = 9 N

The machine exerts a force of 9 newtons on the baseball. This force is calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration.

By determining the acceleration of the baseball using the formula a = (v - u) / t and substituting the given values, we find that the acceleration is 60 m/s^2. Multiplying the mass of the baseball (0.15 kg) by the acceleration gives the force exerted by the machine as 9 newtons.

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Answer:

To determine the molecular formula, we need to find the empirical formula first.

1. Find the moles of CO2 produced:

moles of CO2 = mass of CO2 / molar mass of CO2

moles of CO2 = 2.417g / 44.01 g/mol = 0.05499 mol

2. Find the moles of H2O produced:

moles of H2O = mass of H2O / molar mass of H2O

moles of H2O = 1.484g / 18.02 g/mol = 0.08232 mol

3. Find the moles of C in the compound:

moles of C = moles of CO2

moles of C = 0.05499 mol

4. Find the moles of H in the compound:

moles of H = 2 x moles of H2O

moles of H = 2 x 0.08232 mol = 0.16464 mol

5. Find the moles of O in the compound:

moles of O = (moles of CO2 x 2) + moles of H2O

moles of O = (0.05499 mol x 2) + 0.08232 mol = 0.1923 mol

6. Find the empirical formula:

Divide all the moles by the smallest number of moles to get the simplest whole-number ratio of atoms.

empirical formula = C1H3O1 or CH3O

7. Find the molecular formula:

To find the molecular formula, we need to know the molecular mass of the compound. The molecular mass is 46 g/mol. We can calculate the ratio of the molecular mass to the empirical formula mass:

molecular mass / empirical formula mass = 46 g/mol / 31 g/mol = 1.483

Round this number to the nearest whole number, and multiply the subscripts of the empirical formula by this number to get the molecular formula:

molecular formula = C2H6O2 or C2H6O2

The molecular formula of the compound is C4H4.

To determine the molecular formula of the organic compound, we need to analyze the masses of the elements present and calculate the empirical formula. Given the masses of carbon dioxide (2.417 g) and water (1.484 g) produced during combustion, we can calculate the moles of carbon and hydrogen in the compound.

Moles of carbon:

Using the molar mass of carbon dioxide (44.01 g/mol), we can calculate the moles of carbon dioxide produced:

Moles of carbon dioxide = 2.417 g / 44.01 g/mol = 0.055 moles of CO2

Since there is one mole of carbon in one mole of carbon dioxide, the number of moles of carbon in the compound is also 0.055 moles.

Moles of hydrogen:

Using the molar mass of water (18.015 g/mol), we can calculate the moles of water produced:

Moles of water = 1.484 g / 18.015 g/mol = 0.082 moles of H2O

Since there are two moles of hydrogen in one mole of water, the number of moles of hydrogen in the compound is 2 x 0.082 moles = 0.164 moles.

Now, we can determine the empirical formula by dividing the number of moles of each element by the smallest number of moles (in this case, the number of moles of carbon).

Empirical formula: C0.055H0.055/0.055 = H1

So, the empirical formula of the compound is CH.

To determine the molecular formula, we need to compare the empirical formula mass (CH = 13.02 g/mol) to the given molecular mass (46 g/mol).

Molecular formula: (46 g/mol) / (13.02 g/mol) = 3.53

Since the molecular formula must be a whole number, we round 3.53 to the nearest whole number, which is 4.

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The ice pack gets colder when the inside barrier is broken and the chemicals mix together as instant cold packs employ this type of endothermic reaction.

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Answer:

Density of 40 mL of liquid that has a mass of 20 g = 20 / 40 = 0.5 g / cc

Answer:

Density= mass/volume

Density= 20/40

Density= 0.5g/mL

Answer:

Explanation:

c) fusion combines into one product plus energy