Given the standard enthalpy changes for the following two reactions: (1) 2Fe(s) + O2(g)2FeO(s)...... ΔH° = -544.0 kJ (2) 2Zn(s) + O2(g)2ZnO(s)......ΔH° = -696.6 kJ what is the standard enthalpy change for the reaction:

QUESTION:- Manganese-55 has _____neutrons.

OPTIONS :-

A. 55

B. 30

C. 25

ANSWER:- NUMBER OF NEUTRONS IS EQUAL TO THE DIFFERENCE BETWEEN THE MASS IF THE ATOM AND ATOMIC NUMBER

SO DIFFERENCE IS EQUAL TO :- 55-25 = 30 NEUTRONS.

SO THERE IS 30 NEUTRONS IN SINGLE ATOM OF THE MANGANESE-55 ATOM.

Answer:

the mass of an atom is the sum of proton and neutron which are both concentrated in nocleus of an atom. from the question the mass is given as 55 and the proton is 25.

Explanation:

The menstrual cycle is a reproductive cycle that takes place in the females of the group of primates. The menstrual cycle is divided into four phases:

(i) Menstrual phase: It extends from 1

st

to 4

th

day of the cycle. It occurs in the absence of fertilisation. During this phase, bleeding occurs as the endometrium of the uterus is sloughed off. The menstrual flow consists of secretion of endometrial glands, cell debris, unfertilized ovum. After 4

th

day, once again the FSH secretion from the pituitary is resumed and the new follicle starts developing.

(ii) Follicular phase: When the ovary is in this phase, the uterus enters in the proliferative phase. This takes place from 5

th

to 13

th

day of the cycle. During this phase new primordial follicle in the ovary develops due to the action of FSH from the pituitary. It gradually changes into the Graafian follicle and the production of estrogen starts. Only one follicle develops in one cycle. Corresponding to the changes in the ovary, the uterus also undergoes proliferation. Endometrial glands, stimulated by estrogen do repair process of the uterus.

(iii) Ovulatory phase: During this phase, ovulation takes place. It usually occurs on 14

th

day. Mature Graafian follicle ruptures due to LH secreted by the pituitary. Graafian follicle bursts and releases the ovum. This ovum along with the follicular fluid is picked up by the fimbriae of the infundibulum of the fallopian tube. It passes through the fallopian tube, where, if it happens to meet a sperm, it is fertilised. If not fertilised, the ovum degenerates.

(iv) Luteal phase: It corresponds with the secretory phase in the uterus. It takes place between 15

th

to 28

th

day of the cycle.

Ovarian changes: In the ovary, corpus luteum is formed from an empty Graafian follicle. Progesterone is secreted now. If the ovum is fertilised, corpus luteum is retained. LH and LTH from pituitary help in the maintenance of corpus luteum. If the ovum is not fertilised, corpus luteum degenerates and forms corpus albicans.

Uterine changes: Under the influence of progesterone, there is an increase in the thickness of the endometrium. Endometrial glands grow and become secretory. Progesterone is responsible for the maintenance of pregnancy. When fertilised ovum reaches the uterus, it is implanted and the placenta is formed. Till placenta becomes functional corpus luteum keeps on producing progesterone. But when progesterone source is cut off, endometrium sloughs off and menstruation begins

Answer:

True

Explanation:

When Methyl Pentene is introduced in a chemical reaction with dichloromethane then the major product will be bromomethylpentene. There can be small amount of bromo methyl pentene than the amount of methyl pentene introduced for reaction.

Given concentration of NaCl=15%

Means ,

In every 100g of Solution 15g of NaCl is present .

Now

So ,

[tex]\\ \Large\sf\longmapsto 250\times 15\%[/tex]

[tex]\\ \Large\sf\longmapsto 250\times \dfrac{15}{100}[/tex]

[tex]\\ \Large\sf\longmapsto 37.5g[/tex]

37.5g of NaCl present in 250g of solution.

Answer:

Given concentration of NaCl=15%

Means ,

In every 100g of Solution 15g of NaCl is present .

Now

Given mass=250g

So ,

➡250 × 15%

➡250×15/100

➡37.5g

37.5g of NaCl present in 250g of solution.

Answer:

There are 8Si atoms and 16 O atoms per unit cell

Explanation:

From the question we are told that:

Edge length [tex]l=0.700nm=>0.7*10^9nm[/tex]

Density [tex]\rho=2.32g/cm^3[/tex]

Generally the equation for Volume is mathematically given by

[tex]V=l^3[/tex]

[tex]V=(0.7*10^9)m^3[/tex]

[tex]V=3,43*10^-{22}cm[/tex]

Where

Molar mass of  (SiO2) for one formula unit

[tex]M=28+32[/tex]

[tex]M=60g/mol[/tex]

Therefore

Density of Si per unit length is

[tex]\rho_{si}=\frac{9.96*10^{23}}{3.43*10^22}[/tex]

[tex]\rho=0.29[/tex]

Molar mass of  (SiO2) for one formula unit

[tex]M=28+32[/tex]

[tex]M=60g/mol[/tex]

Therefore

There are 8Si atoms and 16 O atoms per unit cell

Answer:

0.034 M

Explanation:

1/[A] = kt + 1/[A]o

[A] = ?

k= 0.04556

t= 10.0 minutes or 600 seconds

[A]o = 0.50 M

1/[A] = (0.04556 × 600) + 1/0.50

[A] = 0.034 M

Answer:

A. Reactants change into products

Answer:

7.93 × 10⁻⁵ mol

Explanation:

Step 1: Calculate the pressure of hydrogen

The total pressure is the sum of the partial pressures of hydrogen and water vapor.

P = pH₂ + pH₂O

pH₂ = P - pH₂O

pH₂ = 95.090 mmHg - 12.8 mmHg = 82.3 mmHg

We can convert it to atm using the conversion factor 1 atm = 760 mmHg.

82.3 mmHg × 1 atm/760 mmHg = 0.108 atm

Step 2: Convert 15.0 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 15.0 + 273.15 = 288.2 K

Step 3: Calculate the moles of hydrogen

We will use the ideal gas equation.

P × V = n × R × T

n = P × V / R × T

n = 0.108 atm × 0.0173800 L / (0.0821 atm.L/mol.K) × 288.2 K

n = 7.93 × 10⁻⁵ mol

The sum of the squares of two sides of a right angle is equal to the square of the hypotenuse

Answer:

yea all the answers are true

Redox reaction is the transfer of the electron from one species to another. All of the three statements are true about the redox reaction.

A redox reaction is a type of chemical reaction in which the electrons are gained and lost by a species. The positive EMF of the cell results in spontaneous and will move the reaction in the forward direction.  

In a redox reaction, the cathode reaction is comparatively more negative than the reduction potential present at the anode.

Therefore, option E. All I, II, and III are true.

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Answer:

c. 29 J

Explanation:

Step 1: Given data

Step 2: Calculate the temperature change

ΔT = 37 °C - 22 °C = 15 °C

Step 3: Calculate the heat (Q) required to raise the temperature of the lead piece

We will use the following expression.

Q = c × m × ΔT

Q = 0.13 J/g.°C × 15 g × 15 °C = 29 J

Answer:

74%

Explanation:

Step 1: Write the balanced equation

2 C₆H₁₀(l) + 17 O₂(g) ⇒ 12 CO₂(g) + 10 H₂O(g)

Step 2: Determine the limiting reactant

The theoretical mass ratio (TMR) of C₆H₁₀ to O₂ is 164:544 = 0.301:1.

The experimental mass ratio (EMR) of C₆H₁₀ to O₂ is 115:199 = 0.578:1.

Since EMR > TMR, the limiting reactant is O₂.

Step 3: Calculate the theoretical yield of H₂O

The theoretical mass ratio of O₂ to H₂O 544:180.

199 g O₂ × 180 g H₂O/544 g O₂ = 65.8 g H₂O

Step 4: Calculate the percent yield of H₂O

%yield = (experimental yield/theoretical yield) × 100%

%yield = (49 g/65.8 g) × 100% = 74%

Answer:

Percentage yield of H₂O = 74.24%

Explanation:

The balanced equation for the reaction is given below:

2C₆H₁₀ + 17O₂ —> 12CO₂ + 10H₂O

Next, we shall determine the masses of C₆H₁₀ and O₂ that reacted and the mass of H₂O produced from the balanced equation. This is can be obtained as follow:

Molar mass of C₆H₁₀ = 82 g/mol

Mass of C₆H₁₀ from the balanced equation = 2 × 82 = 164 g

Molar mass of O₂ = 32 g/mol

Mass of O₂ from the balanced equation = 17 × 32 = 544 g

Molar mass of H₂O = 18 g/mol

Mass of H₂O from the balanced equation = 10 × 18 = 180 g

SUMMARY:

From the balanced equation above,

164 g of C₆H₁₀ reacted with 544 g of O₂ to produce 180 g of H₂O.

Next, we shall determine the limiting reactant. This can be obtained as follow:

From the balanced equation above,

164 g of C₆H₁₀ reacted with 544 g of O₂.

Therefore, 115 g of C₆H₁₀ will react to produce = (115 × 544)/164 = 381 g of O₂.

From the calculations made above, we can see that a higher mass (i.e 381 g) of O₂ than what was given (i.e 199 g) is needed to react with 115 g of C₆H₁₀.

Therefore, O₂ is the limiting reactant and C₆H₁₀ is the excess reactant.

Next, we shall determine the theoretical yield of H₂O. This can be obtained by using the limiting reactant as shown below:

From the balanced equation above,

544 g of O₂ reacted to produce 180 g of H₂O.

Therefore, 199 g of O₂ will react to produce = (199 × 180)/544 = 66 g of H₂O.

Thus, the theoretical yield of H₂O is 66 g.

Finally, we shall determine the percentage yield. This can be obtained as follow:

Actual yield of H₂O = 49 g

Theoretical yield of H₂O = 66 g

Percentage yield of H₂O =?

Percentage yield = Actual yield /Theoretical yield × 100

Percentage yield of H₂O = 49/66 × 100

Percentage yield of H₂O = 74.24%

Answer:

C2H2 + Br2 → C2H2Br2

Explanation:

Answer:

information is missing

Explanation

reaction is needed to solve the problem

Answer:

When simple sugars such as sucrose (or table sugar) are heated, they melt and break down into glucose and fructose, two other forms of sugar. Continuing to heat the sugar at high temperature causes these sugars to lose water and react with each other producing many different types of compounds.

Answer:

sublimation

Explanation:

solid => liquid   Melting

liquid => solid   freezing

liquid => gas     evaporation

gas => liquid     condensation

solid => gas      sublimation

gas => solid      deposition (e.g.; formation of frost), however some scholars will also refer to this process as sublimation.

Answer:

heat

Explanation:

because it's the cause of change

Answer:

heat

Explanation:

because it is a natural factor that causes the change in Earth's system

Answer:

0.0922 g

Explanation:

Number of moles of acid present = 25/1000 × 0.0981

= 0.00245 moles

Number of moles of base = 5.83/1000 × 0.104

= 0.000606 moles

Since the reaction of HCl and NaOH is 1:1

Number of moles of HCl that reacted with antacid = 0.00245 moles - 0.000606 moles

= 0.001844 moles

From the reaction;

CaCO3 + 2HCl ----> CaCl2 + H2O + CO2

1 mole of CaCO3 reacts with 2 moles of HCl

x moles of CaCO3 reacts with 0.001844 moles ofHCl

x = 1 × 0.001844/2

= 0.000922 moles

Mass of CaCO3 = 0.000922 moles × 100 g/mol

= 0.0922 g

Answer:

Kp = 1.10.

Explanation:

Hello there!

In this case, according to the given information about the chemical reaction at equilibrium, it turns out possible for us to find the partial pressures-based equilibrium expression for the decomposition of phosphorous pentachloride by applying the law of mass action whereas the pressure of products is divided by that of the reactants as shown below:

[tex]Kp=\frac{p_{PCl_3}p_{Cl_2}}{p_{PCl_5}}[/tex]

Now, we plug in the given pressures to obtain:

[tex]Kp=\frac{0.870}{0.688} \\\\Kp=1.10[/tex]

Regards!

Answer:

A. Cation

B. Ne

Explanation:

The ion is positively charged by 2, making it a cation.

The electron configuration of the nearest noble gas Neon is 1s22s22p6

1. A monatomic ion with a charge of 2 has an electronic configuration of 1s22s22p6 is Neon.

2. chemical symbol of the noble gas is Kr (krypton).

Isoelectronic atom or ion has the same number of valence electrons. Krypton has 36 electrons and 36 protons (atomic number 36).

Neon is a chemical element with the symbol Ne and atomic number 10. It is a noble gas. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. It was discovered (along with krypton and xenon) in 1898 as one of the three residual rare inert elements remaining in dry air after nitrogen, oxygen, argon, and carbon dioxide were removed. Neon was the second of these three rare gases to be discovered and was immediately recognized as a new element of its bright red emission spectrum. The name neon is derived from the Greek word, the neuter singular form of  (neos), meaning 'new'. Neon is chemically inert, and no uncharged neon compounds are known. The compounds of neon currently known include ionic molecules, molecules held together by van der Waals forces, and clathrates.

Learn more about Neon

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Explanation:

here's the answer to your question

The pressure of the isoflurane gas at the temperature of 27.4 °C is 0.31 atm.

Gay-Lussac's law states that the pressure of a gas is directly proportional to the absolute temperature when the volume of the gas is kept constant.

Mathematically, Gay Lussca's law can be written as follows:

P/T = k

It is also expressed as the pressure of the gas being directly proportional to temperature.

P ∝ T                    (where V is constant)

or

[tex]\frac{P_1}{T_1} =\frac{P_2}{T_2}[/tex]                                       ................(1)

Given, the initial pressure and initial temperature of the gas:

P₁ = 0.30 atm

and T₁ =  17.9 °C. = 17.9 + 273 = 290.9 K

The final temperature of gas T₂ = 27.4°C = 27.4 + 273 = 300.4 K

Now,  from the equation (1): [tex]P_2=\frac{P_1\times T_2}{T_1}[/tex]

P₂ = (0.30) × (300.4)/290.0

P₂ = 0.31 atm

Therefore, the pressure of the isoflurane at  27.4°C is equal to 0.31 atm.

Learn more about Gay Lussac's law, here:

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Answer:

X

anode

electrons in the wire flow away

anions from salt bridge flow toward

loses mass

Y

cathode

electrons in the wire flow toward

cations from salt bridge flow toward

gains mass

Explanation:

In a galvanic cell, oxidation occurs at the anode while reduction occurs at the cathode. The metal that is more reactive functions as the anode while the less reactive metal functions as the cathode.

Electrons leave the anode and travel via a wire to the cathode. At the anode cations give up electrons and enter into the solution.

At the cathode, cations pick up electrons and are deposited on the cathode leading to a gain in mass at the cathode.

Positive ions from the salt bridge flow towards the cathode while negative ions from the salt bridge flow towards the anode.

Answer:

A) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe

B) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe

Explanation:

The possible sequences that could be obtained from the available dat provided are :

A) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe

B) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe

Trypsin is generally a catalyst  for the breakdown of proteins into smaller peptides ( during the hydrolysis of peptide bonds )  

Answer:

D. An alkene ​

Explanation:

because Ethane is C2H4

Answer:

It's a alkANE. C.

Explanation:

The easiest way to memorize this is to look at the endings. Substances that end in -ANE are alkANEs. Substances that end in -ENE are alkENEs. Substances that end in -YNE are alkYNEs.

Answer:

16

Explanation:

Because the sum of all electron in that compound should be 41 and as it has one electron extra ,total no. of electrons are 42 .

So if we add 26 +16 we get 42

Hence it's correct answer

North America and south africa

Answer:

An electrical conductivity meter (EC meter) measures the electrical conductivity in a solution. It has multiple applications in research and engineering, with common usage in hydroponics, aquaculture, aquaponics, and freshwater systems to monitor the amount of nutrients, salts or impurities in the water.

Answer:

As stored fuels, triacylglycerols have two significant advantages over polysaccharides such as glycogen and starch. The carbon atoms of fatty acids are more reduced than those of sugars, and oxidation of triacylglycerols yields more than twice as much energy, gram for gram, as that of carbohydrates.

Explanation: