Ethylene oxide (EO) is prepared by the vapor-phase oxidation of ethylene. Its main uses are in the preparation of the antifreeze ethylene glycol and in the production of poly(ethylene terephthalate), which is used to make beverage bottles and fibers. Pure EO vapor can decompose explosively:
Liquid EO has ΔH°f =-77.4 kj/mol and ΔH° for its vaporization 5 569.4 J/g. (a) Calculate ΔH°rxn for the gas-phase reaction.

The entropy of a system (such as a kilogram of liquid water) is a measure of the amount of thermal energy that is unavailable to do work. As the temperature of a system increases, the entropy of the system will also generally increase.

This is because as the temperature increases, the molecules in the liquid water will have more kinetic energy, which means they will move around more and have more possible microstates. This increase in possible microstates leads to an increase in entropy.

Additionally, increasing the temperature also increases the disorder of a system, as the molecules have more kinetic energy, they have more ways to distribute the energy, and the distribution becomes more random. The increase in disorder also contributes to the increase in entropy.

It's important to notice that the increase in entropy is a natural tendency of closed systems, which the second law of thermodynamics states that the entropy of an isolated system can only increase over time, it will never decrease.

The modified amino acid derived from tyrosine that acts as a neurotransmitter is dopamine. So, the correct answer is:
d. dopamine

Neurotransmitters are chemical messengers that your body can't function without. Their job is to carry chemical signals (“messages”) from one neuron (nerve cell) to the next target cell. The next target cell can be another nerve cell, a muscle cell or a gland.

There are more than 40 neurotransmitters in the human nervous system; some of the most important are acetylcholine, norepinephrine, dopamine, gamma-aminobutyric acid (GABA), glutamate, serotonin, and histamine.

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Answer:

Released energy

Explanation:

Answer:

The answer is: Released energy

Hope this helped <33

Explanation:

The pH of the solution after 28.0 ml of NaOH have been added to the acid exists 0.85.

The balanced reaction between base and acid exists;

NaOH + HCl → NaCl + H₂O

NaOH exists a strong base and HCl exists a strong acid therefore complete dissociation. Stoichiometry of acid to base exists 1: 1.

The number of moles of base added - 0.5 M /1000 mL/L × 28.0 mL = 0.014 mol

the number of acid moles present - 0.5 M /1000 mL/L × 50.0 mL = 0.025 mol.

acid reacts with base 1: 1 ratio

Therefore excess amount of acid present - 0.025 - 0.014 = 0.011 mol

Total volume = 50.0 + 28.0 = 78.0 mL

[H⁺] = 0.011 mol/0.078 L = 0.14 M

Therefore, pH = -log [H⁺]

substitute the values in the above equation, we get

pH = -log(0.14)

simplifying the above equation, we get

pH = 0.85.

Therefore, the pH of the solution after 28.0 ml of NaOH have been added to the acid exists 0.85.

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The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of the reactant and product is conserved. Therefore the mass of PbCl\(_2\) is 19.6g.

According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier. Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved.

NaCl + Pb (NO\(_3\)) \(_2\)(aq)  → PbCl\(_2\) (s) ↓  + 2 NaNO\(_3\) (aq)

Mass of NaCl =15.90 Grams

Mass of  Pb (NO\(_3\)) \(_2\)=12.10grams

According to law of conservation f mass

mass of reactant = mass of product

Substituting the values we get

15.90g +  12.10g = mass of PbCl\(_2\)+ 8.40g

mass of PbCl\(_2\) =19.6g

Therefore the mass of PbCl\(_2\) is 19.6g.

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Chemistry => The Mole => Percent of water in a Hydrate

We have a compound that is hydrated with "n" moles of water. To determine the moles of water, what we will do is take as a base a mole of the dry compound, that is, 1 mol of Na2SO4.

We will determine the mass of one mol of the dry compound and the difference between the hydrated compound and the dry compound will be the water content.

Let's see what is the molar mass of the dry compound: Na2SO4

Element Mass

Na 2 x 22.99 =45.98 g/mol

S 1 x 32.065 = 32.065 g/mol

O 4 x 15.999 = 63.996 g/mol

Sum 142.04 g/mol

So, we have that one mol of Na2SO4 has a mass of 142.04.

Now, the water in 1 mol of the hydrated compound will be:

Now, we divide the mass obtained by the molar mass of water, 18.01 g/mol:

In the hydrated compound, we have 9 moles of H2O for each mol of Na2SO4.

Therefore the ANSWER will be B. 9

Explanation:

So 2 moles of carbon reacts with 2 moles of oxygen to produce 2 moles of CO2.

A mole of CO2 molecules (we usually just say “a mole of CO2”) has one mole of carbon atoms and two moles of oxygen atoms. The atom ratio and the mole ratio of the elements are identical! 1-).

1 mole of CO2 = 1 × 12 + 2 × 16 = 44 g. 2 mole of CO2 = 2 × 44.0 = 88.0 g.

Answer:

it looks smaller for sure ^_^

The solid state rectifier is primarily made of silicon. The correct option is c.

Solid state rectifiers are devices that are used to convert AC voltage to DC voltage. They are primarily made of semiconducting materials such as silicon or germanium. These materials have the property of having a conductivity that is in between that of a conductor and an insulator.

In the case of a solid state rectifier, the semiconducting material is typically silicon. Silicon is preferred for its high melting point, high thermal conductivity, and its ability to form a stable oxide layer. This oxide layer is used to create a p-n junction, which allows for the conversion of AC voltage to DC voltage. Therefore, the correct answer is c. silicon.

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Answer:

I don't know

Explanation:

I'm sorry I didn't learn this in my life,I have never reach in this level

It's important to know that the reaction must have the total mass involved before and after due to the law of conservation of mass. This means that the total mass number of the left side of the reaction must be equal to the right side. So, we have the following

Notice that 235 is the mass number of U, 1 is the mass number of the neutron, X represents the mass number of the unknown element, 141 represents the mass number of Ba, and 3 represents the mass number of three neutrons. This means X should have a mass number of 92, which is the element Kr.

Therefore, the mass number is 92 and the chemical symbol is Kr.

Answer:

The answer would be [HCIO][OH-]

_________

[CIO-]

Explanation:

So, the answer would be (b).

Answer:

0.0899 moles of oxygen (O2).

Explanation:

What is given?

Mass of sodium oxide (Na2O) = 11.15 g.

Molar mass of Na2O = 62 g/mol.

Step-by-step solution:

First, let's state the balanced chemical equation:

Let's calculate the moles of Na2O that are in 11.15 g of Na2O, using its molar mass:

Now that we have the moles of Na2O, let's do the stoichiometry: you can see in the chemical equation that 1 mol of oxygen (O2) reacted produces 2 moles of Na2O, so by doing a rule of three based on this data, the calculation will look like this:

The answer is that we need 0.0899 moles of oxygen (O2) to produce 11.15 g of sodium oxide.

The negatively charged subatomic particles that J.J. Thomson discovered are now called electrons. Subatomic particles can be either neutral, positively charged, or negatively charged. Protons, for example, are positively charged subatomic particles. Electrons, on the other hand, are negatively charged subatomic particles

What are charged subatomic particles? Subatomic particles can be either neutral, positively charged, or negatively charged. Protons, for example, are positively charged subatomic particles. Electrons, on the other hand, are negatively charged subatomic particles. Neutrons are the third type of subatomic particle, but they are neutral, which means they do not have a charge. What did J.J. Thomson discover? J.J. Thomson was a British physicist who, in the late 19th century, conducted a series of experiments on cathode rays. Cathode rays are beams of electrons that are produced in a vacuum tube when an electric current is passed through it. Thomson used cathode rays to investigate the structure of atoms. In 1897, Thomson discovered that cathode rays are made up of negatively charged subatomic particles. He named these particles "corpuscles," but they are now known as electrons. Thomson's discovery of the electron revolutionized atomic physics and led to the development of the electron model of the atom. Electrons are important because they are responsible for chemical reactions and are involved in electricity and magnetism. They are negatively charged and are located outside the nucleus in the electron cloud. Electrons are also the smallest subatomic particle and have a mass of 9.10938356 x 10-31 kg (0.0005485799 atomic mass units).

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The mass (in grams) of water needed to be circulating each hour in order to keep the reactor at or below 95°C is 627390 g

The following data were obtained from the question:

The mass of water needed can be obtained as illustrated below:

Q = MCΔT

210000000 = M × 4.184 × 80

210000000 = M × 334.72

Divide both sides by 334.72

M = 210000000 / 334.72

M = 627390 g

Thus, we can conclude that the mass of the water needed is 627390 g

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The paddle-like, charged transmembrane domains of potassium channels may be the primary voltage sensors.

A transmembrane domain (TMD) is a protein domain that spans a membrane. Although some TMDs, like those found in porins, can adopt a different conformation, most TMDs typically adopt an alpha helix topological configuration.

In close proximity to the proteins' N-terminus, the transmembrane domain serves as an anchor. Type IV (N-terminus in): The transmembrane domain serves as an anchor and is placed close to the protein's C-terminus.

Six transmembrane domains and one pore region (6TM/1P) make up voltage-gated K+ channels, and the N- and C-terminal domains are both found in the cytoplasm. The positively charged amino acids that are evenly spaced throughout the S4 segment are important for the channel's ability to sense voltage.

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Answer:

b

Explanation:

The statement that is true about what can occur in a chemical change is b. Elements may combine to form compounds.

A chemical change can be described as the change which do take place when the substance's composition is been altered which could bring about the formation of another substance.

It should be noted that in the chimical change there is uaually a formation of a new product after one or more substance must have reacted together which implies that in this kind of change there is usuall a new substance that will be formed in the process.

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63.4845 grams of solid sodium cyanide should be added to 0.500 L of a 0.174M hydrocyanic acid solution to prepare a buffer with a pH of 8.730.

For preparing a buffer with a specific pH, we can use the Henderson-Hasselbalch equation for acidic buffers:

pH = pKa + log([A-]/[HA])

In this case, the acid is hydrocyanic acid (HCN) and its conjugate base is cyanide ion (CN-).

pH = 8.730

Ka (HCN) = 4.00 × 10^(-10)

Volume (V) = 0.500 L

Concentration of hydrocyanic acid ([HA]) = 0.174 M

To find the concentration of the conjugate base ([A-]), we rearrange the Henderson-Hasselbalch equation:

[A-]/[HA] = 10^(pH - pKa)

Substituting the given values:

\([A-]/[0.174] = 10^{8.730} - (-log10(4.00 * 10^{-10})))\)

\([A-]/[0.174] = 10^{8.730 + 10}\)

[A-]/[0.174] = \(10^{18.730}\)

[A-] =  \(10^{18.730}\) * [0.174]

[A-] ≈ 2.593 M

Now, we need to calculate the number of moles of cyanide ion (CN-) required to achieve a concentration of 2.593 M in a volume of 0.500 L:

moles of CN- = [A-] * V

            = 2.593 * 0.500

            = 1.2965 moles

The molar mass of sodium cyanide (NaCN) is approximately 49 g/mol. Therefore, the mass of solid sodium cyanide required can be calculated:

mass = moles of CN- * molar mass of NaCN

     = 1.2965 * 49

     ≈ 63.4845 grams

Rounded to three significant figures, the mass of solid sodium cyanide required to prepare the buffer is approximately 63.5 grams.

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Answer: During succession, new species move into an area and colonize it.

Explanation: Ecological succession refers to the process of change in the composition and structure of an ecosystem over time. It occurs due to the interactions between the biotic (living) and abiotic (non-living) components of an environment. As succession progresses, new species gradually establish and thrive in the area, leading to a change in the species composition. This process can occur over a long period of time, ranging from decades to centuries, depending on various factors such as environmental conditions and the specific type of succession.

After fertilization, the egg takes about 6-10 days to move down to the uterus and implant in the uterine lining. The implantation process is a crucial aspect of the early stages of pregnancy, and it typically occurs between days 6 and 10 after fertilization.

Implantation is a critical step in pregnancy because it is the first stage in the process of fetal development. The egg needs to implant in the uterus for the developing embryo to receive nutrients and oxygen. If implantation doesn't occur, the embryo will not be able to survive, and the body will naturally terminate the pregnancy.

In conclusion, the process of implantation takes between 6-10 days, and it's a critical step in pregnancy. It's the first stage in the process of fetal development and is necessary for the embryo to receive nutrients and oxygen. If implantation doesn't occur, the body will naturally terminate the pregnancy.

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Answer:

Molecules change speed based on temperature and state of matter. The warmer they are, the faster they move and vice versa. Solids are at a lower temperature than gases and liquids, which means the molecules are moving slower, and hold together better, also explaining why solids aren't malleable.

The particles gather kinetic energy and accelerate as the temperature rises.

Kinetic energy is defined as an object is the energy it has since it is in motion. It is explained as the amount of effort required to move a mass-based body from rest to the indicated velocity. The body keeps its kinetic energy, which it acquired during acceleration, unless its speed changes.

The actual average speed of the particles is influenced by both their mass and temperature; at a given temperature, larger particles travel more slowly than lighter ones. Temperature and the physical state of the materials affect the speed of molecules. They move more quickly in warmer temperatures and vice versa. Since solids have lower temperatures than gases and liquids, their molecules move more slowly and adhere to one another more tightly, which also explains why solids aren't bendable.

Thus, the particles gather kinetic energy and accelerate as the temperature rises.

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If an object's mass is 70 g, and its volume is 10cm cubed,  its density is 7 centimeter cube.

The density of any solid substance is the unit of the area occupied by it in per centimeter of the cube of the volume in the given sample and calculated by dividing the mass and the volume of the compound unit will be centimeter cube.

The mass of the given object is 70 gram and the volume is given is 10 cm to find the density,

                       Density = mass of object / volume of object

substituting the value in the formula,

                 Density = 70 / 10

                 Density = 7 centimeter cube.

Therefore, the density of the given object will be 7 centimeter cube if  an object's mass is 70 g, and its volume is 10cm cubed.

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Answer:

ΔT = 0.843 °C

Explanation:

Given data:

Heat added = 0.484 J

Mass of water = 0.1372 g

Temperature increase = ΔT = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Specific heat capacity of water is 4.184 j/g.°C

Now we will put the values in formula.

0.484 j = 0.1372 g × 4.184 j/g.°C× ΔT

0.484 j = 0.574j/°C× ΔT

ΔT = 0.484 j / 0.574j/°C

ΔT = 0.843 °C

Answer:

A.)physical B.)physical C.)physical D.)chemical

Answer A) liquid

Explanation:

Indefinite shape and definite volume describe the liquid state. The correct option is A.

The liquid state of matter is a state in which the matter can be kept in any shape of desire and the particles of matter are slightly away from each other and mostly has the tendency to form a hydrogen bond with other chemicals.

In this state, the volume is fixed but the shape is not as because of loosely bonded atoms the atoms of matter can move or flow from one place to another so they must be kept in a container of the desired shape.

Therefore, the Correct option is A.Indefinite shape and definite volume describe the liquid state.

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Answer:

Explanation:

The kinetic energy of an object can be found by using the formula

\(k = \frac{1}{2} m {v}^{2} \\ \)

m is the mass

v is the velocity

From the question we have

\(k = \frac{1}{2} \times 25 \times {2.5}^{2} \\ = 12.5 \times 6.25 \\ = 78.125 \: \: \: \: \: \: \: \: \)

We have the final answer as

Hope this helps you

The standard free energy change in kJ for the reaction 2Fe³⁺(aq) + Pb(s) → 2Fe²⁺(aq) + Pb²⁺(aq) is 128.8 kJ.

To determine the standard free energy change in kJ for the reaction 2Fe³⁺(aq) + Pb(s) → 2Fe²⁺(aq) + Pb²⁺(aq), we must follow these steps.

1. The given redox reaction can be represented as 2Fe³⁺(aq) + Pb(s) → 2Fe²⁺(aq) + Pb²⁺(aq)

2. The half-reactions can be represented as:

Fe³⁺(aq) + e⁻ → Fe²⁺(aq) ..... (Reduction)

Pb²⁺(aq) + 2e⁻ → Pb(s) ........ (Oxidation)

For Fe³⁺ → Fe²⁺, E° = +0.77 V

Pb²⁺ → Pb, E° = -0.13 V

On reversing the oxidation reaction, the standard reduction potential value also changes in sign.

2Pb(s) → 2Pb²⁺(aq) + 4e⁻ ..... (Reverse of oxidation)

Pb²⁺(aq) + 2e⁻ → Pb(s) .......... (Oxidation)

Here, the standard reduction potential value is: -[-0.13] V = +0.13 V

Using the Nernst equation:

Ecell = E°cell - (0.0592/n) log(Q)

In standard conditions, the reaction quotient Q = 1.

Ecell = E°cell - (0.0592/n) log(1)

Ecell = E°cell

At equilibrium, ΔG = -nFE = -nFE°cell

Using the values in the equation,

-nFE°cell = -2 × 96500 × (0.77 - 0.13) joules

Dividing by 1000 to convert the value into kJ:

nFE°cell = 128.8 kJ

Thus, the standard free energy change in kJ for the given reaction is 128.8 kJ.

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Explanation:

can damage the tissues and organs and further impair oxygenation of blood