how many atoms of one formula unit in Fe2O3

Answer:

Chlorine

Chlorine has two naturally occurring isotopes. In a sample of chlorine, 75.77% of the atoms are Cl-35, with a mass of 34.97amu.

Explanation:

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Chlorine has two naturally occurring isotopes. In a sample of chlorine, 75.77% of the atoms are Cl-35, with a mass of 34.97amu.

List the known and unknown values ​​and edit the problem. Convert each percentage value into a decimal by dividing it by 100. Multiply this number by the atomic mass of that spot. Mix together each isotope to find the median atomic mass.

To calculate the maximum percentage of each isotope in a sample of something, chemists usually divide the atomic number of a particular isotope by the total number of atoms of all that isotope and multiply the result by 100.

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Answer:

d

Explanation:

nCl2 = 0,1 -> nRCI = 0,2

M muéi = R + 35,5 = 14,9/0,2

-> R = 39: R la K

Answer:

d

Explanation:

nCl2 = 0,1 -> nRCI = 0,2

M muéi = R + 35,5 = 14,9 / 0,2

-> R = 39: R la K

Answer:

C₄H₄N₂

Explanation:

Given that:

M+ = 80.

It implies that the number of nitrogen present in the molecule must also be even according to the Nitrogen rule.

So from the Formula CHN, the nitrogen will have to be 2 because if we make use of 4, it will exceed the given M+ which is 80.

∴

C₄ = 4 × 12 = 48

H₄  = 4 × 1   = 4

N₂ =  2 × 14 = 28      

                      80      

As such, the molecular formula of the compound is C₄H₄N₂

Answer:

20,8ml  NaCl 6M

Explanation:

C1V1 = C2V2

Answer:

Selective serotonin reuptake inhibitors (SSRIs)

Explanation:

A synaptic cleft is a space that separates two neurons thereby forming a junction between two or more neurons. The synaptic cleft helps in the transfer of nerve impulse from one neuron to the other.

5-HT is found in the enteric nervous system located in the gastrointestinal tract and it helps in modulating cognition, memory, sleep, and numerous physiological processes.

Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine and citalopram are used to increase the level of 5-HT in the synaptic cleft by inhibiting its reuptake into the presynaptic terminal.

Answer:

It is so because heat is flowing from hot body to cold body, and there is no direct contact between the body. It explains correctly the mode of transmission of thermal energy through the process of radiations.

Explanation:

Fun fact:

How does thermal energy transfer by radiation?

Radiation. All objects transfer energy to their surroundings by infrared radiation . The hotter an object is, the more infrared radiation it gives off. No particles are involved in radiation, unlike conduction.

Answer:

2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)

Explanation:

In a redox reaction, we must ensure that the number of electrons gained equals the number of electrons lost in the reduction and oxidation half reaction equations respectively.

Having that in mind;

Oxidation half reaction;

2Rb(s) ---->2Rb^+(aq) + 2e

Reduction half equation;

Sr^2+(aq) + 2e---> Sr(s)

Hence, the overall redox reaction equation is;

2Rb(s) + Sr^+(aq) → 2Rb^+ (aq) + Sr(s)

Answer:

the last one probably

Explanation:

Answer:

6.02 × 10²⁷ km

Explanation:

Step 1: Calculate the height of the stack of pennies

A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies (6.02 × 10²³ pennies) one on top of the other on Earth's surface, the height of the stack of pennies would be:

6.02 × 10²³ pennie × 1.0 mm/1 pennie = 6.02 × 10²³ mm

Step 2: Convert 6.02 × 10²³ mm to kilometers

We will use the following conversion factors.

6.02 × 10²³ mm × 1 m/10³ mm × 1 km/10³ m = 6.02 × 10²⁷ km

Answer:

See explanation and image attached

Explanation:

Nitrogen trichloride NCl3 contains one nitrogen and three chlorine atoms. Each chlorine atom has three lone pairs of electrons while nitrogen has one lone pair of electrons.

The molecule geometry of the molecule is trigonal pyramidal while it's electron domain geometry is tetrahedral. Nitrogen is the central atom and is found in sp3 hybridization.

There is no formal charge on the molecule.

Answer:

"The total pressure in a mixture of gases is equal to the sum of partial pressures of each gas"

Explanation:

Dalton's law of partial pressures state that, in a mixture of gases, the total pressure is equal to the sum of the partial pressure exerted by each gas of the mixture. The equation is:

Total pressure = Partial pressure Gas 1 + Partial pressure Gas 2 + .... + Partial pressure Gas n

To complete the sentence we can say:

"The total pressure in a mixture of gases is equal to the sum of partial pressures of each gas"

Considering the Dalton's partial pressure, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.

The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{A} +P_{B}[/tex]

This relationship is due to the assumption that there are no attractive forces between the gases.

Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. The mole fraction is a dimensionless quantity that expresses the ratio of the number of moles of a component to the number of moles of all the components present.

So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:

[tex]P_{A} =x_{A} P_{T}[/tex]

In summary, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.

Learn more:

Answer:

Regla de Markovnikov En fisicoquímica orgánica, la regla de Markovnikov es una observación respecto a la reacción de adición electrófila.Regla de Markovnikov En fisicoquímica orgánica, la regla de Markovnikov es una observación respecto a la reacción de adición electrófila.

Explanation:

Answer:

(a) Pair 1: H₂S and HS⁻

    Pair 2: NH₃ and NH₄⁺

(b) Pair 1: HSO₄⁻ and SO₄⁻

    Pair 2: NH₃ and NH₄⁺

(c) Pair 1: HBr and Br⁻

    Pair 2: CH₃O⁻ and CH₃OH

(d)  Pair 1: HNO₃ and NO₃⁻

     Pair 2: H₃O⁺

Explanation:

When an acid loses its proton (H⁺), a conjugate base is produced.

When a base accepts a proton (H⁺), it forms a conjugate acid.

(a) H₂S is an acid. When it loses a proton, it forms the conjugate base HS⁻.

    NH₃ is a base. When NH₃ gains a proton, it forms the conjugate acid NH₄⁺

(b) The acid HSO₄⁻ loses a H⁺ ion and forms the conjugate base SO₄²⁻.

     The base NH₃ accepts a H⁺ ion to form the conjugate acid NH₄⁺.

(c) HBr is an acid. When loses the H⁺ ion, it forms the conjugate base Br⁻.

   CH₃O⁻ accepts a H⁺ ion to form the conjugate acid CH₃OH.

(d) HNO₃ loses a proton to form the conjugate base NO₃⁻.

    H₂O gains a proton to form the conjugate acid H₃O⁺.

Answer:

See explanation

Explanation:

The atomic number refers to the number of protons in the nucleus, it also tells us the number of electrons in the neutral atom since the atom is electrically neutral because the number of protons and electrons are equal.

If an atom has the atomic number 11, then the electrons in the atom are arranged in the shells in the order; 2, 8, 1.

Two electrons are found in the innermost shell, eight electrons are found in the next shell and one electron is found on the outermost shell.

The nucleus of the atom is composed of a total of 23 nucleons; 11 protons and 12 neutrons.

Answer:

(a) The moles of CuSO₄ is 3.125 × 10⁻³ moles.

(b) The moles of Cu is 3.125 × 10⁻³ moles.

(c) The mass of Cu is 0.2 g.

Explanation:

Given:

Mass of CuSO₄ = 0.5 g

Molar mass of CuSO₄ = 160 g/mol

The given balanced chemical equation is:

[tex]2Al+3CuSO_4\rightarrow 3Cu+Al_2(SO_4)_3[/tex]

Part (a):

Calculating the moles of CuSO₄.

[tex]\text{Moles of } CuSO_4=\frac{\text{Mass of }CuSO_4}{\text{Molar mass of }CuSO_4}\\\\\text{Moles of } CuSO_4=\frac{0.5g}{160g/mol}\\\\\text{Moles of } CuSO_4=3.125\times 10^{-3}mol[/tex]

Thus, the moles of CuSO₄ is 3.125 × 10⁻³ moles.

Part (b):

Calculating the moles of Cu.

From the balanced chemical equation, we conclude that:

As, 3 moles of CuSO₄ reacts to give 3 moles of Cu

So, 3.125 × 10⁻³ moles of CuSO₄ reacts to give 3.125 × 10⁻³ moles of Cu

Thus, the moles of Cu is 3.125 × 10⁻³ moles.

Part (c):

Calculating the mass of Cu.

Mass of Cu = Moles of Cu × Molar mass of Cu

Molar mass of Cu = 64 g/mol

Mass of Cu = (3.125 × 10⁻³ mole) × (64 g/mol)

Mass of Cu = 0.2 g

Thus, the mass of Cu is 0.2 g.

Answer:

A photon is absorbed by the atom.

More energy is emitted or absorbed for case 2

Explanation:

According to the Bohr model of the atom, electrons occur in energy levels. The energy of each level is fixed. However, electrons can absorb photons and move from a lower to higher energy level or emit photons and move from a higher to a lower energy level.

In each case, the energy absorbed or emitted is equal to the difference in energy between the two energy levels.

Since energy level 3 is much higher than energy level 2, the electron absorbs more energy in moving from energy level 1 to energy level 3 than it absorbs when moving from energy level 1 to energy level 2.

Answer:

1.49 × 10⁹ years

Explanation:

Step 1: Calculate the rate constant (k) for the nuclear decay of U-235

The decay follows first-order kinetics with a half-life (t1/2) of 703 × 10⁶ years. We can calculate "k" using the following expression.

k = ln2/ t1/2 = ln2 / 703 × 10⁶ y = 9.86 × 10⁻¹⁰ y⁻¹

Step 2: Calculate the time elapsed (t) so that the final amount ([U]) is 23.0% of the initial amount ([U]₀)

For first order kinetics, we will use the following expression.

ln ([U]/[U]₀) = -k × t

ln (0.230[U]₀/[U]₀) = -9.86 × 10⁻¹⁰ y⁻¹ × t

ln 0.230 = -9.86 × 10⁻¹⁰ y⁻¹ × t

t = 1.49 × 10⁹ y

Answer:

Kf = 0.389.

Explanation:

Hello there!

In this case, it turns out possible for us to solve this problem by firstly writing the equilibrium chemical equation and equilibrium expression for the formation of this complex:

[tex]B+C\rightleftharpoons BC\\\\Kf=\frac{[BC]}{[B][C]}[/tex]

Thus, we firstly calculate the concentrations at equilibrium, knowing that the reaction extent in this case is 0.00500mol (same as the formed moles of BC):

[tex][B]=[C]=\frac{0.0350L*1.00mol/L-0.00500mol}{0.0700L} =0.429M[/tex]

[tex][BC]=\frac{0.00500mol}{0.0700L} =0.0714M[/tex]

And finally, the equilibrium constant:

[tex]Kf=\frac{0.0714}{[0.429][0.429]}\\\\Kf=0.389[/tex]

Regards!

Explanation:

1. As you go across a period, what is a useful comparison point?

A.

oxides

2. Most elements are

A.

allotropes

3. A metalloid is a(n) __ conductor of heat and electricity than a metal.

A.

better

4. What causes the formation of allotropes?

A.

pressure

As you move __and __ elements become more metallic.

A.

left, down

5. All of the following metalloids form allotropes except

A.

B

6. What is a chemical property of a metal?

A.

malleable

Answer: hello some part of your question is missing below is the missing part

In an experiment to determine the % of ascorbic acid in Vitamin C Tablets by Titration with Potassium Bromate,

answer:

Oxidation half reaction of Vitamin C

Explanation:

The solution will turn cloudy dark purple even after reaching endpoint when allowed to settle with time. because of the Oxidation half reaction of Vitamin C. also during the Titration process few drops of starch solution will be added to help determine the endpoint of the experiment .

Answer:

C. The mass stays the same because the total number of atoms does not change

Explanation:

According to the law of conservation of matter/mass, matter cannot be created nor destroyed, hence, the amount of matter in the reactants must be the same amount in the products.

Using the photosynthetic reaction as a case study, carbon dioxide (CO2) and water (H2O) are the compounds that go into the reaction (reactants) while glucose and oxygen (O2) are the products of the reaction.

Using the law of conservation of matter to explain, the total mass of both the reactants and products stays the same because the total number of atoms does not change i.e. if 6 atoms of Carbon starts the reaction, 6 atoms of carbon will end it.

Answer:

liquid is the right answer k

Answer:

liquid

Explanation:

ask correctly so that your points cant make fun of others

Answer:

See explanation

Explanation:

I) from the question;

500 × 10^-3 g dissolves in 100ml

xg dissolves in 1000ml

x = 500 × 10^-3 g × 1000ml/100 ml

x= 5 g/L

Mass concentration = molar concentration × molar mass

Molar concentration = Mass concentration/ molar mass

Molar concentration = 5g/L/419 g/mol

Molar concentration = 0.0119 M

ii) To prepare this solution, measure out 500mg with a weighing balance. Transfer the solid to a standard 100 ml volumetric flask. Make up to the 100ml mark with distilled water.

iii) mass concentration of the solution = 50 g/L

Volume of the solution= 100 ml

Mass of the solid = 50 g/L × 100/1000 L

Mass of solid = 5g

This 5g was taken for 10 days, hence a total of 50 g

Since the normal dose of the drug is 40g for ten days, the patient will suffer from kidney problems because he/she has taken the drug above the recommended dosage.

Answer:

H+

Explanation:

it's H+

as you see hydrogen ion it could H+

It last longer because it slows down the spread of bacteria.

Temperature, concentration, particle size, use of a catalyst.

Answer:

Alkanes

Cycloalkanes

Ring flip

Lower

Angle

Equatorial

Axial

Explanation:

For alkanes, the general molecular formula is CnH2n+2 while for cycloalkanes, the general molecular formula is CnH2n.

The cycloalkanes could undergo a ring flip in which axial and equatorial hydrogen atoms are interconverted.

The lower energy conformation of alkanes is the anti conformation and not the gauche conformation due to steric strain.

When the bond angle in alkanes deviate from the ideal 109.5°, an angle strain has occurred.

For bulky groups, the equatorial position his preferred since it has more room than the axial position.

Answer:

Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

A process such as a chemical reaction that removes water.The atoms which constitute the molecule of water that is removed.

Hence,It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent,

Thus, it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.

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