State the postulate of Bohr theory

Answers

Answer 1

Answer:

Bohr's model of the hydrogen atom is based on three postulates:

1) An electron moves around the nucleus in a circular orbit,

2) An electron's angular momentum in the orbit is quantised,

3) The change in an electron's energy as it makes a quantum jump from one orbit to another is always accompanied by the emission or absorption of a photon. Bohr's model is semi-classical because it combines the classical concept of electron orbit (postulate 1) with the new concept of quantisation ( postulates 2 and ).

Related Questions

which element is trigonal pyramidal molecular shape ? a) NF3. b) BCL3 c) COCL2 d) CLO3- e) BRF3

Answers

Answer:

A.) NF₃

D.) ClO₃⁻

Explanation:

To determine the molecular shape of the molecules, you need to:

1.) Calculate the total valence electrons in the molecule

-----> The sum of the element's valence electrons

2.) Draw the Lewis structure

What do the letters “P.P.E” stand for in chemical

Answers

Answer:

Personal Protective Equipment

Explanation:

Some examples of PPE are safety glasses, lab coats, steel-toed shoes, etc.

The purpose of PPE is to keep the user from getting injured when using dangerous equipment or chemicals.

The molar heat of fusion of gold is 12.550 kJ mol–1. At its melting point, how much mass of melted gold must solidify to release 235.0 kJ of energy?

Answers

The mass of melted gold to release the energy would be 3, 688. 8 Kg

How to determine the mass

We have quantity of energy is;

Q = n × HF

n = number of moles

HF = heat of fusion

Let's find number of moles

235.0 = n × 12.550

number of moles = [tex]\frac{235}{12. 550}[/tex] = 18. 725 moles

Note that molar mass of Gold is 197g/ mol

Number of moles = mass/ molar mass

Mass = number of moles × molar mass

Mass = 18. 725 × 197

Mass = 3, 688. 8 Kg

Thus, the mass of melted gold to release the energy would be 3, 688. 8 Kg

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1.______ language is the ability to understand what’s said.

2. When babies handle objects, they learn that they can
make something happen. This helps them begin to
understand and _______.

3. Caregivers can encourage language development by _____
to the baby.

4.______ is the ability of an infant to understand when
an object is present even if he or she can't see it.

5. Language development and thinking ability are _______.

6. Toddlers gain self-confidence when they _______.
Caregivers should expect toddlers to _______.

7.Caregivers should help children select television programs to watch and _______ the time they spend in this activity.

8. Superhero and fantasy play should be tempered with discussing the differences between _______ and reality.

Answers

The 1 month old baby sees up to 30 cm away, following objects and people that move around him and fixing his gaze on bright and flashy objects. To say that he wants something or that something is bothering him, the baby usually expresses himself through crying.

What is baby development?

1.Clear language is the ability to understand what’s said.

2. When babies handle objects, they learn that they can

make something happen. This helps them begin to

understand and do.

3. Caregivers can encourage language development by sign

to the baby.

4.imagine is the ability of an infant to understand when

an object is present even if he or she can't see it.

5. Language development and thinking ability are indispensable.

6. Toddlers gain self-confidence when they make mistakes.

Caregivers should expect toddlers to mistakes.

7.Caregivers should help children select television programs to watch and monitor the time they spend in this activity.

8. Superhero and fantasy play should be tempered with discussing the differences between fantasy and reality.

With this information, we can conclude that If your baby does not respond to stimuli and even as the months go by, simple steps of the baby's development are not happening, such as smiling, turning around, crawling, the pediatrician will follow up and refer the competent specialist to carry out evaluation tests to investigate a possible delay. psychomotor.

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Determine the mass of CO2 produced when 51.2 g of CaO is reacted with 50.0 g of C according to the unbalanced chemical equation:

CaO (s) + C (s) ---> CaC2 (s) + CO2 (g)

Hint: You will need to balance the equation first.

Answers

The mass of CO2 produced will be 8.01 grams

Stoichiometric problem

The balanced equation of the reaction is written as:

[tex]2CaO (s) + 5C (s) --- > 2CaC_2 (s) + CO_2 (g)[/tex]

The mole ratio of CaO and C is 2:5 from the balanced equation.

Mole of 51.2 g CaO = mass/molar mass = 51.2/56 = 0.91 moles

Mole of 50.0 g C = 50/12 = 4.17 moles

From the mole ratio, 0.91 mole CaO will require 5/2 x 0.91 = 2.28 moles C.

This means 4.17 moles carbon is excessive. In other words, C is the limiting reagent.

The mole ratio of C and CO2 is 5:1. Thus, the equivalent mole of CO2 that will be produced from 0.91 moles C will be:

0.91/5 = 0.182 moles.

Mass of 0.182 moles CO2 = mole x molar mass = 0.182 x 44 = 8.01 grams

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characteristic ions of water: OH- and H3O+

Answers

Answer:

H2O

Explanation:

water is made up of 1 hydrogen snd 2 oxygen

what is the type of chemical reaction that vinegar, baking soda, and dish soap have?

Reaction 1: Two reactions are occurring:
sodium bicarbonate + acetic acid  sodium acetate + carbonic acid
carbonic acid  carbon dioxide + water
Add a teaspoon of dish soap to a cup of vinegar and mix well. Add a table spoon of baking soda to the vinegar soap mixture.

What are the two reactions that occur? I only noticed one and that was when I added baking soda.

what is the type of chemical reaction that vinegar, baking soda, and dish soap have (Combustion, decomposition, etc.) and what is the balanced chemical equation of this reaction?

Answers

Answer:

Explanation:

The reaction between baking soda (sodium bicarbonate) and vinegar (dilute acetic acid) generates carbon dioxide gas, which is used in chemical volcanoes and other projects.

what is the cation of Al2(SO4)3

Answers

Answer:

Al has a 3+ charge, and SO4 has a 2- charge. So, it takes 3 of the SO4 anions to balance 2 of the Al cations. So, you get Al2(SO4)3

a 3.211 g sample of gypsum a hydrated salt of magnesuim sulfate, MgSO4.XH2OIS HEATED IN A CRUCIBLE UNTIL A CONSTANT MASS IS REACHED . THE MASS OF THE ANHYDROUS MgSO4 IS 2.539g
a) calculate the percentage by the mass of water in the hydrated MgSO4.xH2O
b) calculate the moles , the amount of H2O released during heating and the amount (in moles) of the anhydrates MgSO4 remaining after heating
c) calculate the value of x in MgSO4.xH2O/ This is the empirical formula of the hydrated magnesium sulfate

Answers

From the calculation, the compound is MgSO4.2H2O.

What is a hydrated salt?

A hydrated salt is a salt that contains molecules of the water of crystallization.

a) Percentage of the water of crystallization = 3.211 g - 2.539g/ 3.211 g * 100/1 = 21%

b) Number of moles of water of crystallization = 3.211 g - 2.539g/ 18 g/mol =

0.037 moles

c) Number of moles of anhydrous salt = 2.539g/120 g/mol = 0.021 moles

Number of moles of hydrated salt = 3.211 g/120 + 18x

Hence;

0.021 = 3.211 /120 + 18x

0.021(120 + 18x) = 3.211

2.52 + 0.378x = 3.211

0.378x = 3.211 - 2.52

x = 3.211 - 2.52/ 0.378

x = 2

Hence the compound is MgSO4.2H2O

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3 Br2 + 6 OH1- → 5 Br1- + BrO31- + 3 H2O
If 8.5 moles of Br2 are reacted with an unlimited supply of OH1-, how many moles of BrO31- can be formed?

Answers

Answer:

2.8 moles BrO₃⁻

Explanation:

To find the amount of moles, you need to convert moles Br₂ to moles BrO₃⁻ using the mole-to-mole ratio. This ratio is made up of the balanced equation coefficients in front of the relevant molecules.

3 Br₂ + 6 OH⁻ -----> 5 Br⁻ + 1 BrO₃⁻ + 3 H₂O

8.5 moles Br₂ 1 mole BrO₃⁻
----------------------- x ---------------------- = 2.8 moles BrO₃⁻
3 moles Br₂

A can of soda is opened at room temperature and a hiss is heard. Which factor has changed inside the container?

Answers

The factor that has changed inside the container would be the pressure.

Pressurized containers

Sodas in cans are preserved using a gas, carbon dioxide to be precise.

The gas is used to preserve the drink and sealed under pressure.

When a can of soda is opened, the first thing that escapes is the carbon dioxide gas. By doing so, the pressure in the can reduces.

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Find the number of moles and the number of atoms of Hydrogen and s in 10 moles of H₂S

Answers

Answer:

See below

Explanation:

H2 S shows that each mole of H2S has two moles of H in it

so 10 moles of H2S would have 20 moles of H

Each mole is Avagadro's Number of atoms

20 moles * 6.022 x10^23 atoms/mole = 120.44 x 10^23 toms of H

H2S has one mole of S for each mole of H2S

there are then 10 moles of S

10 * 6.022 x 10^23 = 60.22 x 10^23 atoms of S

Count the significant digits in 95700 kg

Answers

5 significant figures

A drop of water with a mass of 0.48 g is vaporized at 100 ∘C and condenses on the surface of a 55- g block of aluminum that is initially at 25 ∘C . If the heat released during condensation goes only toward heating the metal, what is the final temperature in Celsius of the metal block? (The specific heat capacity of aluminum is 0.903 J/(g⋅∘C ).)
Express the temperature in Celsius to two significant figures.

Answers

The final temperature in Celsius of the metal block is 49°C.

How to find the number of moles ?

Moles water = [tex]\frac{\text{Given mass}}{\text{Molar Mass}}[/tex]

= [tex]\frac{0.48\ g}{18\ \text{g/mol}}[/tex]

= 0.0266 moles

Heat lost by water = 0.0266 mol x 44.0 kJ/mol

= 1.17 kJ

= 1170 J [1 kJ = 1000 J]

Heat lost = Heat gained

Heat gained by aluminum = 1170 J

1170 = 55 x 0.903 (T - 25) = 49.7 T - 1242

1170 + 1242 = 49.7 T

T = 48.5°C (49°C at two significant figures)

Thus from the above conclusion we can say that The final temperature in Celsius of the metal block is 49°C.

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What state of matter is Polaris, the north star?

A. Plasma
B. Liquid
C. Light
D. Gas

Answers

The state of matter of Polaris, the north star is gas.

What are stars made of?

Stars are made up of a mixture of hot gases.

The mixture consists of helium and hydrogen. Hydrogen burns into helium to give starts a shining appearance when observed from a far distance.

Thus, the state of matter of all stars, including the north star, is gas.

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what’s the amino acid for this?

Answers

The amino acid for this should be Arginine. I am not entirely sure.

A weather balloon calibrated at 0.00 °C to
have a volume of 20.0 L has what volume at
-36.2 °C assuming pressure is held
constant? Answer is in L

Answers

Answer:

17.3 L

Explanation:

With all other variables held constant, you can find the missing volume using the Charles' Law equation:

V₁ / T₁ = V₂ / T₂

In this equation, "V₁" and "T₁" represent the initial volume and temperature. "V₂" and "T₂" represent the final volume and temperature. Before we can solve, we need to convert Celsius to Kelvin (because we don't want negative numbers or temp. of 0).

V₁ = 20.0 L V₂ = ? L

T₁ = 0.00 °C + 273.15 = 273.15 K T₂ = -36.2 °C + 273.15 = 236.95 K

V₁ / T₁ = V₂ / T₂ <----- Charles' Law equation

20.0 L / 273.15 K = V₂ / 236.95 K <----- Insert values

0.0732 = V₂ / 236.95 K <----- Simplify left side

17.3 L = V₂ <----- Multiply both sides by 236.95

GIVING BRAINLIEST!!!!!!!!! (and the rest of my points)
The Himalayan balsam plant makes seeds in pods and releases them when it is ready, while the Surinam toad absorbs its eggs into its own back until they are ready to come out. How are the adaptations of the balsam and the toad similar?

A. They are behaviors that allow the plant and the animal to reproduce through shorter life cycles.
B. They are behaviors that protect the plant and the animal from predators.
C. They are life cycle differences that protect the offspring and help them to survive.
D. They are physical characteristics that allow the offspring to survive in cold weather conditions.

Answers

They are life cycle differences that protect the offspring and help them to survive. The correct option is C.

Life cycle adaption

Some organisms have life cycle features that ensure that their population is perpetuated in subsequent generations.

Such features include ensuring that propagules are only released when they are mature and making sure that eggs are hatched and offspring become viable before they are allowed to move to the environment.

These actions will make sure that the propagules of offspring have what it takes to survive in their new environment.

In other words, these life cycle features are embedded in the genome of organisms as a way to survive the environment.

Thus, the features of the Himalayan balsam plant and that of the Surinam toad are more or less targeted toward the same thing - the survival of their offspring.

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Answer: Option (C) is correct, They are life cycle differences that protect the offspring and help them to survive.

Explanation: Hope it helps!

Good luck!!!

What classifies a substance as an element?
What classifies a substance as a compound?

Actually, answer what the question is asking and give a short answer. No copying and pasting.

Answers

The difference between an element and a compound is that an element is a substance made of same type of atoms, whereas a compound is made of different elements in definite proportions.Examples of elements include iron, copper, hydrogen and oxygen. Examples of compounds include water (H2O) and salt (Sodium Chloride - NaCl).

What classifies a substance as an element?

What classifies a substance as a compound?

Actually, answer what the question is asking and give a short answer. No copying and pasting.

Answers

Elements cannot be broken down into simpler substances by any or series of chemical reactions.

A compound can be broken done by chemical reactions

Element and compound

An element can be defined as species of atoms having a certain number of protons in their nuclei and pure substance of that species.

Elements cannot be broken down into simpler substances by any or series of chemical reactions.

A compound can be defined as a chemical substance that is composed of numerous identical molecules containing atoms from more than one element and held together by chemical bonds.

A compound can be broken done by chemical reactions

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A gas that has a volume of 13 liters, a temperature of 25 0C, and an unknown pressure has its volume increased to 27 liters and its temperature decreased to 15 0C. If I measure the pressure after the change to be 1.3 atm, what was the original pressure of the gas?

Answers

This is an exercise in the general or combined gas law.

To start solving this exercise, we obtain the data:

Data:V₁ = 13 LtT₁ = 25 °C + 273 = 298 kV₂ = 27 LtT₂ = 15 °C + 273 = 288 kP₁ = 1.3 atmP₂ = ¿?

We use the following formula:

P₁V₁T₂ = P₂V₂T₁ ⇒ General Formula

Where

P₁ = Initial pressureV₁ = Initial volumeT₂ = Initial temperatureP₂ = Final pressureV₂ = Final volumeT₁ = Initial temperature

We clear the general formula for the final pressure.

[tex]\large\displaystyle\text{$\begin{gathered}\sf P_{2}=\frac{P_{1}V_{1}T_{2} }{V_{2}T_{1}} \ \to \ Clear \ formula \end{gathered}$}[/tex]

We substitute our data into the formula to solve:

[tex]\large\displaystyle\text{$\begin{gathered}\sf P_{2}=\frac{(1.3 \ atm)(13\not{l})(288\not{k} )}{(27 \not{l})(298 \not{K})} \end{gathered}$}[/tex]

[tex]\large\displaystyle\text{$\begin{gathered}\sf P_{2}=\frac{4867.2}{8046} \ atm \end{gathered}$}[/tex]

[tex]\boxed{\large\displaystyle\text{$\begin{gathered}\sf P_{2}=0.604 \ atm \end{gathered}$}}[/tex]

If I measure the pressure after the change by 1.3 atm, the original pressure of the gas will be 0.604 atm.

Boyels law lab report

Answers

Boyle's law is a model used in chemistry and physics to estimate the pressure behavior of gases in a closed system.

What is Boyle's law?

Boyle's law is a model used to calculate pressure and volume relationships among gases in a thermodynamically closed system.

This law states that the pressure of a given gas represents an inversely proportional measurement of its volume in steady conditions.

In conclusion, Boyle's law is a model used in chemistry and physics to estimate the pressure behavior of gases in a closed system.

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5. Which of the following personal protective equipment is selected based on a
chemical's IDLH value?
O A. Respirator
O B. Eyewear
O C. Body suit
O D. Gloves

Answers

Answer is A. Respirator
Reason

IDLH atmospheres require a full-face piece, pressure demand self-contained breathing apparatus (SCBA) or supplied-air respirator (SAR) with self-contained auxiliary air supply.

Respirator - It is chosen based on a chemical's IDLH value, ensuring protection against immediate life-threatening respiratory hazards.

Option (A) is correct.

The correct personal protective equipment (PPE) selected based on a chemical's IDLH (Immediately Dangerous to Life or Health) value is a respirator. IDLH value is a critical safety parameter that represents the maximum concentration of a chemical in the air above which an individual could suffer immediate or long-term health effects, such as life-threatening respiratory issues.

When a chemical's IDLH value is exceeded, it becomes essential to use appropriate respiratory protection. A respirator helps filter and remove harmful contaminants from the air, preventing inhalation and protecting the wearer's respiratory system.

Different types of respirators are available, ranging from simple dust masks to full-face air-purifying respirators or supplied-air respirators, based on the specific hazard and IDLH value of the chemical involved.

Eyewear, body suits, and gloves are essential PPE, but they are not specifically selected based on the chemical's IDLH value.

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if 14.0 g of aluminium reacts with excess sulfuric acid to produce 75.26 g of aluminium sulfate, what is the percent yield?

Answers

Taking into account definition of percent yield, the percent yield for the reaction is 84.88%.

Reaction stoichiometry

In first place, the balanced reaction is:

2 Al + 3 H₂SO₄ → Al₂(SO₄)₃ + 3 H₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Al: 2 moles H₂SO₄: 3 molesAl₂(SO₄)₃. 1 moleH₂: 3 moles

The molar mass of the compounds is:

Al: 27 g/moleH₂SO₄: 98 g/moleAl₂(SO₄)₃: 342 g/moleH₂: 2 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

Al: 2 moles ×27 g/mole= 54 gramsH₂SO₄: 3 moles ×98 g/mole= 294 gramsAl₂(SO₄)₃: 1 mole ×342 g/mole= 342 gramsH₂: 3 moles ×2 g/mole= 6 grams

Mass of aluminium sulfate formed

The following rule of three can be applied: if by reaction stoichiometry 54 grams of aluminium form 342 grams of aluminium sulfate, 14 grams of aluminium form how much mass of aluminium sulfate?

[tex]mass of aluminium sulfate=\frac{14 grams of aluminium x342 grams of aluminium sulfate}{54 grams of aluminium}[/tex]

mass of aluminium sulfate= 88.67 grams

Then, 88.67 grams of aluminium sulfate can be produced if 14.0 g of aluminium reacts with excess sulfuric acid.

Percent yield

The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.

The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:

[tex]percent yield=\frac{actual yield}{theorical yield} x100[/tex]

where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.

Percent yield for the reaction in this case

In this case, you know:

actual yield= 75.26 gramstheorical yield= 88.67 grams

Replacing in the definition of percent yields:

[tex]percent yield=\frac{75.26 grams}{88.67 grams} x100[/tex]

Solving:

percent yield= 84.88%

Finally, the percent yield for the reaction is 84.88%.

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PLEASE ANSWER THIS FAST... tysm
●what will happen to the texture off egg shell if you place it in.
1. Coca cola

2. orange juice

3. grape juice

4. normal water

5. a dark coloured sugary drink like sting

Answer all these correctly please

thanks

Answers

Answer:

4. the egg shell you place in normal water

Look at Table 4 in the procedure portion of the experiment. Calculate the pH you would expect each of the buffer solutions (A, B, C, D, and E) to be using the Henderson-Hasselbalch equation, assuming that the solutions of acetic acid and sodium acetate are equimolar.

Answers

The pH of the buffer solutions as determined using the Henderson–Hasselbalch equation are:

A. pH = 4.75B. pH = 4.05C. pH = 3.75D. pH = 5.75E. pH = 5.45

What is the pH of the solutions?

The pH of a buffer is determined using the Henderson–Hasselbalch equation shown below:

pH = pKₐ + log([A⁻]/[HA])

A. Volume of acetic acid = 5 mL; Volume of sodium acetate = 5 mL; pka of acetic acid = 4.75