One of the postulates of bohr's atomic model of a moving electron is that angular momentum of a moving electron is quantized. Explain its meaning and calculate the angular momentum of third orbit (i.e n=3)
The angular momentum of an electron in the third Bohr orbit of a hydrogen atom is given by mvr=3h÷2π
What is momentum?Momentum is defined as the amount of motion occurring in something that is moving, or the force that drives something forward to keep it moving.
Bohr never assumed stable electronic orbits with the electronic angular momentum quantized as
l=mvr = [tex]\frac{nh}{2pi}[/tex]
Quantization of angular momentum means that the radius of the orbit and the energy will be quantized as well.
Bohr assumed that the discrete lines seen in the spectrum of the hydrogen atom were due to transitions of an electron from one allowed orbit/energy to another.
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What would cause a nucleus to be unstable?
A. An unequal number of protons and electrons
B. Too few quarks within the nucleus of the atom
C. An equal number of protons and neutrons
D. An imbalance between the electrostatic and strong nuclear forces
SUBMIT
The instability of the nucleus is due to an imbalance between the electrostatic and strong nuclear forces, which is option D.
A nucleus can become unstable if there is an imbalance between the electrostatic repulsion between protons and the strong nuclear force that holds the nucleus together. The electrostatic repulsion between protons tends to push them apart, while the strong nuclear force acts to hold the protons and neutrons together.
If the number of protons in the nucleus is too large, the electrostatic repulsion becomes stronger, making the nucleus unstable. Similarly, if the number of neutrons is too large or too small compared to the number of protons, it can also lead to an imbalance in the forces and instability of the nucleus.
Therefore, the correct option is option d.
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Ch3chclch(ch3)ch2ch2ch2ch2br name the molecule iupac rules please
Answer:
1-bromo-6-chloro-5-methylheptane
Explanation:
There are 3 substituents, 1 chlorine, 1 bromine, and 1 methyl group.
The longest carbon chain consists of 7 carbons.
There are no double bonds, based on the saturation and substituents.
So you have a 1-bromo-6-chloro-5-methylheptane.
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If a substance can be given a chemical formula can be considered to be a(n) __________.
If a substance can be given a chemical formula can be considered to be a(n) compound.
What is a compound?A pure substance made up of two or more different elements combined chemically in a fixed ratio is called a compound.
Compounds are substances composed of different elements bonded chemically; only chemical reactions break the chemical bonds or create new chemical bonds leading a compound to form other substances.
Hence, if a substance can be given a chemical formula can be considered to be a(n) compound.
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A student needs to standardize a base solution by titration with an acid solution of known concentration. She finds the volume of the acid solution needed to reach the endpoint for a sample of the base solution. Arrange the steps in the order that will allow her to determine the concentration of the base solution.
The steps usually involves adding the known solution (the titrant) to a known quantity of the unknown solution (the analyte) until the reaction is complete which can be understood in detail as below with the help of through out process of titration.
What is Titration ?A titration is a technique used to work out the concentration of an unknown solution based on its chemical reaction with a solution of known concentration.
Steps in order to determine the concenteration of base solution ;
(Acid-Base Titration)
Choose the titrant.Choose the titrate.Select the normality of the titrate.Choose the volume of the liquid to be pipetted out.Select the indicator.Start titration.End point is noted at the colour change of the solution.From the final reading the normality of titrant can be calculated by the equation:N₁V₁=N₂V₂
After finding the normality, the amount of given substance in the whole of the given solution can be calculated by the equation:Mass = Equivalent weight x Normality \ Volume {1000}
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what is chemical energy
Answer:
chemical energy is the energy of a chemical substance that is stored in the bonds of chemical compounds and is released when they undergo a chemical reaction and transform into another substance
lighting is more likely to strike a metal tower than a rubber hose because:
A. metal is a conductor and rubber is an insulator
B. the light from the tower attracts the electrons
C. the tower is negatively charged and will accept electrons
D. metal is an insulator and subnet is a conductor
Which best explains why a firework being ignited is an example of an exothermic reaction and not an endothermic
reaction ?
O The fireworks produce colors.
O The fireworks give off heat.
O Igniting the fireworks requires energy.
O Igniting the fireworks makes an odor.
The best explanation for why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction is:
The fireworks give off heat.
Heat is emitted into the environment in an exothermic reaction. When a firework is lit, it undergoes a number of chemical processes inside the firework combination, which produces gases and produces a great deal of heat. Fireworks' distinctive visual display and audible effects are produced when heat is released as light and sound.
In contrast, heat is taken from the environment during an endothermic reaction. If a reaction were endothermic, it would need an outside energy source to continue, and because it would be absorbing heat from its environment, it would feel chilly to the touch.
However, because they release heat and energy and brighten the night sky, fireworks are instances of exothermic reactions.
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Select the correct answer.
What is the purpose of the arrow in a chemical equation?
OA. It indicates the direction in which the reaction occurs.
OB.
It separates the elements from the compounds.
OC.
It indicates the direction of increase in the number of molecules.
It indicates the direction of heat movement in a reaction.
O D.
Reset
Next
Answer: A. It indicates the direction in which the reaction occurs.
3.the three major types of radioactive decay of an unstable nucleus are alpha particles, beta particles, and gamma rays.
explain how alpha decay works and how it causes a transmutation. be sure to note all changes to the nucleus in your explanation.
write the equation for the alpha decay of uranium-234.
explain how beta decay works and how it causes a transmutation. be sure to include all changes to the nucleus in your explanation.
write the equation for the beta decay of iodine-131.
a) Alpha decay occurs when an unstable nuclide emits an alpha particle, (which is just a helium-4 atom), which contains 2 protons and 4 neutrons. This means that transmutation has occurred (since a nuclide of a different element will be produced), and this newly produced nuclide will have 2 fewer protons and 4 fewer neutrons than the original nuclide.
b) [tex]^{234}_{92} \text{U} \longrightarrow ^{4}_{2} \text{He}+^{230}_{90} \text{Th}[/tex]
c) Alpha decay occurs when an unstable nuclide emits a beta particle, (also known as an electron). This causes transmutation (since a nuclide of a different element will be produced), and this newly produced nuclide will have 1 more proton than the original nuclide.
d) [tex]^{131}_{53} \text{I} \longrightarrow ^{0}_{-1} \beta+^{131}_{54} \text{Xe}[/tex]
What is the mass in grams of 4.85 x 10^22 Al atoms? (Report your answer to two places past the decimal
Answer:
2.17 gm Al
Explanation:
First, find the number of moles . Then multiply by the mole weight of aluminum.
# moles = 4.85 x 10^22 / 6.022 x 10^23 = .08053 moles
.0805 moles * 26.981 gm/mole = 2.173 gm
What is the name of this molecule?
Answer:
The name of this molecule structure is 1-Butyne
The name of the given molecule according to IUPAC is 1-Butyne. Thus, option C is correct.
What is IUPAC nomenclature?The IUPAC nomenclature is given as the standard naming technique that is used to name a chemical compound. It is named with the following main rules.
The triple bond compound is an alkyne with the suffix -yne. The development of the name to the given structure is therefore given by counting the number of carbon atoms, and the location of the triple bond.
There are 4 carbon atoms in the structure with the triple bond at carbon 1, therefore the name will be 1-Butyne. Hence, option C is correct.
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how can one establish whether a liquid sample extracted from a plant is pure
How many grams of
diphosphorus trioxide, P2O3, are
required to produce 10.2 moles of
phosphorous acid, H3PO3?
P2O3 + 3H₂O → 2H3PO3
[?] g P₂O3
From the equation, we know that for every 2 moles of phosphorous acid produced, 1 mole of diphosphorus trioxide is consumed.
This means that we need to find the mass of 10.2/2 = 5.1 moles of diphosphorus trioxide.
The atomic mass of phosphorous is 30.973761998 g/mol.The atomic mass of oxygen is 15.9994 g/mol.So, the formula mass of diphosphorus trioxide is:
2(30.973761998)+3(15.9994)=109.945723996 g/mol.Thus, 5.1 moles have a mass of:
5.1(109.945723996), which is about 561 g (to 3 sf)Answer: 561 g
Explanation:
which trends increase to the lower left: metallic character, non-metallic character, atomic radius, ionization energy, electronegativity?
Metallic character increase to the lower left of the periodic table.
What is periodicity?Periodicity is the regular variation in the properties of an element across a period and down a group.
The following properties of elements show periodicity:
metallic character,non-metallic character,atomic radius, ionization energy,electronegativityThe properties that shows increasing trend to The lower left of the periodic table is metallic character.
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Which of the following is the best definition of a chemical change?
A. A change in a substance where one or more new substances form
B. A change in a substance where no new substance forms
C. A change in a substance where energy is conserved
OD. A change in a substance where a phase change occurs
Answer:A is correct
Explanation:
Prepare a project report on various samples of
a) a mixture
b) a compound
c) an element ( metal or non metal)
( 2 from each ) highlighting the main characteristics features of elements, compounds and mixtures.
Answer:
please mark me as brain list
Explanation:
Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions
Example: Water decomposes into a mixture of hydrogen and oxygen, on the other hand, cannot be decomposed into simpler substances. They are therefore the elementary, or simplest, chemical substances elements.
Each element is represented by a unique symbol. The notation for each element can be found on a periodic table of elements.
The elements can be divided into three categories that have characteristics properties: metals, nonmetals and semimetals. Most elements are metals, which are found on the left and toward the bottom of the periodic table. A handful of nonmetals are clustered in the upper right corner of the periodic table. The semimetals can be found along the dividing line between the metals and the nonmetals.
How do you separate a honey and water solution?
Answer:
Keep it undisturbed for some time and let it settle down. Then use a separating funnel, to separate them both
Explanation:
A 5 Complete the sentences using words from the list. You may use them once, more than once, or not at all.
increases；decreases；stays the same
a) When liquid water boils, the distance between the particles ____
b) When liquid water boils, the strength of the attractive forces between the particles ___
c) When steam condenses, the speed of movement of the particles ___
Answer
Number 1. increase
number 2 . decrease
number 3. decrease
The Cabbage Indicator
Your hypothesis about how to indicate various levels of pH, both acid and base with an indicator:
What liquids were used in the investigation?
Vinegar is an acid. Which liquids produced colors like vinegar?
Baking soda is a base. Which liquids produced colors like baking soda?
Did you see any that did not fit into either color group? If so which one(s)?
Could you determine the relative pH of the liquids by the varying color of the cabbage indicator?
Do you think you could add drops of a base solution into an acid solution until they indicate neutral?
How would you be able to tell when a neutral pH was obtained?
What did you find out from this investigation? Be thoughtful in your answer.
.A solution that serves as a pH indicator may be made using red cabbage, which is frequently available in homes. In essence, the color of the cabbage depends on the acidity of the solution and a pigment molecule called flavin or anthocyanin.
To determine whether a material is an acid or a base, red cabbage indicator is a purple-colored solution
Vinegar is an acid and its pH value is less than 7 and hence
Red color is produced
Baking soda is base and its pH value is greater than 7 and between 8-9
and the color produced is sky blue
Bleach is the green which is also a basic and because the pH value is 10-11
Householder cleaner is having pH 11-13 which is basic and hence the yellow is the color of household cleaner .
A basic solution goes away from being basic and toward the center of the pH scale when an acid is introduced. The base is "neutralized" in this manner.
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How many moles of water form
when would be required to react
with 183.5 g Ba(OH)2 reacts with
excess HBr?
2HBr + Ba(OH)2 → BaBr2 + 2H₂O
[?] mol H₂O
Will sodium iodide react with bromine to produce sodium bromide and iodine? Why or why not?
Question 10 options:
A) Yes, because bromine has lower activity than iodine
B) No, because bromine has higher activity than iodine
C) No, because bromine has lower activity than iodine
D) Yes, because bromine has higher activity than iodine
I believe its either B or D
Answer:
C
Explanation:
The higher the period the higher the activity of an element, therefore, since iodine is in period 6 and bromine is in period 5, the described reaction is not possible due to the fact that bromine is less active
How can you use quantitative chemistry and reaction dynamics to explain and optimize industrial processes and reactions that happen in everyday life?
The quantitative chemistry is helps in measuring the quantity of chemicals or chemical agents of food while making some dish or cleaning agent. It also helps in determining the quantity of macromolecules in the body, like protein, lipid, etc.
What is quantitative chemistry?
Quantitative chemistry is a branch which tells the quantity of substances, chemicals. The mass, volume etc. It also helps in determining the molecules and toxic level in the body.
Thus, the quantitative chemistry is helps in measuring the quantity of chemicals or chemical agents of food while making some dish or cleaning agent. It also helps in determining the quantity of macromolecules in the body, like protein, lipid, etc.
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1. 10.0 g of CaCO 3 on heating gave 4.4 g of CO 2 and 5.6 g of CaO. The observation is in agreement with the law of conservation of mass.
2. hydrogen and oxygen are combined to form two compounds the hydrogen content in one of the compound is 5.93 % and another is 11.2 % is this obey the law of multiple proportion.
3. On analysis it was found that the black oxide of Copper and red oxide of copper contains 80 and 89% of copper respectively Is this obeys the law of multiple proportion.
4.when 8.4 G of NaHco3 is added to the solution of Acetic Acid weighing 20 gram if it is observed that 4.4 gram of Co2 is released into the atmosphere and Residue is left Behind what is the mass of left Residue.
Answer:
According to the law <br> Mass of reactants = mass of product, here <br> `underset(10 g)(CaCO_(3))rarr underset(4.4 g)(CO_(2))+underset(x)(CaO)` <br> Hence, x = 10 g - 4.4 g = 5.6 g <br> Which is mass of CaO.dIn the first compound <br> Hydrogen = 5.93 % <br> Oxygen = `(100-5.93)% = 94.07 %` <br> In the second compound <br> Hydrogen = 11.2 % <br> Oxygen `= (100-11.2)%=88.8%` <br> In the first compound the number of parts by mass of oxygen that combine with one part by mass of hydrogen `=(94.07)/(5.93)=15.86` parts ...(The ratio of Cu combining with fixed weight of oxygen in black and red oxide is 1 : 2 respectively. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.) {Check something more in the above attachment!}Refer to the above attachmentExplanation:
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A 2. 75-l container filled with co2 gas at 25°c and 225 kpa pressure springs a leak. When the container is re-sealed, the pressure is 185 kpa and the temperature is 10°c. How many moles of gas were lost?.
Answer:
Moles Lost = 0.0335 moles
Explanation:
This type of question requires the Ideal Gas Law equation. The equation looks like this:
PV = nRT
In this formula,
-----> P = pressure (kPa)
-----> V = volume (L)
-----> n = number of moles
-----> R = constant (8.314 L*kPa/mol*K)
-----> T = temperature (K)
(Step 1)
To find how many moles were lost, you first need to find how many moles you had to begin with. This can be done by plugging the starting values into the equation and solving for "n". But first, you need to convert Celsius to Kelvin (by adding 273.15).
P = 225 kPa R = 8.314 L*kPa/mol*K
V = 2.75 L T = 25°C + 273.15 = 298.15 K
n = ?
PV = nRT
(225 kPa)(2.75 L) = n(8.314 L*kPa/mol*K)(298.15 K)
618.75 = n(2478.8191)
0.250 = n
(Step 2)
Next, you need to find the number of moles in the container after it has been re-sealed. The volume is the same because the container did not change. The process should be the same as above.
P = 185 kPa R = 8.314 L*kPa/mol*K
V = 2.75 L T = 10°C + 273.15 = 283.15 K
n = ?
PV = nRT
(185 kPa)(2.75 L) = n(8.314 L*kPa/mol*K)(283.15 K)
508.75 = n(2354.1091)
0.216 = n
(Step 3)
Finally, you can find the number of moles lost by subtracting the final amount of moles from the original amount. When doing this calculation, I used the value of the moles saved in my calculator (with more decimal places) to get a more accurate number.
Moles Lost = Initial Moles - Final Moles
Moles Lost = 0.250 moles - 0.216 moles
Moles Lost = 0.0335 moles
2 NH3 + 3 CuO →3 Cu + N₂ + 3 H₂O
In the above equation, how many grams of N₂ can be made when 4.3 moles of CuO are consumed?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer
as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your
answer incorrect.:
Element Molar Mass
Hydrogen 1
Nitrogen 14
Copper 63.5
Oxygen 16
40.1g of nitrogen gas is produced.
The equation given is
2 NH₃ + 3 CuO →3 Cu + N₂ + 3 H₂O
This equation is already balanced.
When 3 moles of CuO are consumed, 1 mole of nitrogen gas is produced.
We get 1 mole of nitrogen from 3 moles of copper oxide.
We need to find the number of moles of nitrogen gas produced when 4.3 moles of copper oxide are consumed.
4.3/3 x 1 = 1.433 mols
1.433 mols of nitrogen gas are producedThe molar mass of nitrogen gas is 14+14 = 28gThe amount of nitrogen gas produced in grams is 28x1.433 = 40.1g40.1g of nitrogen gas can be made when 4.3 moles of CuO are consumed.
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Short Response
Directions: Base your answers to questions 6 and 7 on the information below and your knowledge of chemistry.
Ammonia, NH3(g), can be used as a substitute for fossil fuels in some internal combustion
engines. The reaction between ammonia and oxygen in an engine is represented by
the unbalanced equation below.
NH3(g) + O₂(g) → N₂(g) + H₂O(g) + energy
6. Balance the equation in the space below for the reaction of ammonia and oxygen, using the
smallest whole-number coefficients.
7. Show a numerical setup for calculating the mass, in grams, of a 4.2-mole sample of 0₂. Use 32
g/mol as the gram-formula mass of 0₂.
Answer:
6.)
7.) 134.4 g O₂
Explanation:
The unbalanced equation:
NH₃ (g) + O₂ (g) ---> N₂ (g) + H₂O (g) + energy
Reactants: 1 nitrogen, 3 hydrogen, 2 oxygen
Products: 2 nitrogen, 2 hydrogen, 1 oxygen
The balanced equation:
4 NH₃ (g) + 3 O₂ (g) ---> 2 N₂ (g) + 6 H₂O (g) + energy
Reactants: 4 nitrogen, 12 hydrogen, 6 oxygen
Products: 4 nitrogen, 12 hydrogen, 6 oxygen
To convert from moles to grams, you need to multiply the starting value (4.2 moles) by the molar mass (32.00 g/mol). The molar mass can serve as a conversion because it technically means there are 32.00 grams O₂ per every 1 mole. It is important to arrange this ratio in a way that allows for the cancellation of units (the desired unit should be in the numerator).
4.2 moles O₂ 32.00 g
-------------------- x ---------------- = 134.4 g O₂
1 mole
Using the balanced chemical equation, determine the
number of moles of aluminum required to react with 7.53
mol of chlorine.
2Al(s) + 3Cl2(g) -> 2AlCl3(s)
Answer:
5.02 mol
Explanation:
n(Al) : n(Cl)
2 : 3
x : 7.53
3x = 15.06
n(Al) = 5.02mol
Why do you think it is important to record your data with all the decimals provided by the instruments even if they are zero? how does this help with data analysis?
It is important to record your data with all the decimals provided by the instruments even if they are zero because it increases the accuracy of the measurement.
What is accuracy in experimentation?Accuracy refers to the ability to take correct measurement values during a specific experiment and/or observational procedure.
Accuracy is a fundamental issue in data analysis and helps to obtain conclusions from a given experimental procedure.
In conclusion, it is important to record your data with all the decimals provided by the instruments even if they are zero because it increases the accuracy of the measurement.
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hydrochloride acid +_________ zinc chloride +hydrogen
Answer:
Hydrochloride acid + Zinc = Zinc Chloride + Hydrogen
Explanation:
When Hydrochloride acid and Zinc react, it results in the formation of Zinc chloride and hydrogen.
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