You are given 0.39 mol of niobium (Nb). How many grams of niobium do you have?

Chemical changes are changes that alter the identity or the chemical composition of substances at the atomic level.

When a substance changes chemically, the identity of the substance changes.

In other words, chemical changes are changes that occur to substances such that the entire chemical properties of the substances change.

These changes happen at the atomic levels of substances. Sometimes, the changes can also be physical as well.

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Answer:

1.48 x 10²⁵ molecules ZnO

Explanation:

To find the amount of molecules, you need to (1) convert grams to moles (via molar mass) and then (2) convert moles to molecules (via Avogadro's Number). It is important to arrange the conversions/ratios in a way that allows for the cancellation of units.

Molar Mass (ZnO): 65.380 g/mol + 15.998 g/mol

Molar Mass (ZnO): 81.378 g/mol

Avogadro's Number:

6.022 x 10²³ molecules = 1 mole

2,000 g ZnO           1 mole              6.022 x 10²³ molecules
---------------------  x  -----------------  x  ---------------------------------------  =  
                                81.378 g                          1 mole

=  1.48 x 10²⁵ molecules ZnO

Answer:

What was Niels Bohr's most important discovery? Niels Bohr proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. This atomic model was the first to use quantum theory, in that the electrons were limited to specific orbits around the nucleus.

Explanation:

Subjects Of Study: atomic model

Answer:

four 0.5 times 10 to the 23rd Adams of Neptune

Explanation:

Answer:

0.75 ( 6.02 × 10²³) = 4.515 x 10²³

Explanation:

0.75 ( 6.02 × 10²³) = 4.515 x 10²³

Answer:

Radium Nitride

A radioactive element is radium. See what "radioactive" actually means.

Atoms make up the elements. Since most atoms are stable, they do not change over time. However, some of the heaviest atoms disintegrate and transform into different types. "Radioactivity" is the term for this breakdown or disintegration.

Each radioactive element releases rays that decay or disintegrate at a specific pace. There is no known way to speed up or slow this rate. Some changes happen quickly, some take longer, but no matter what, man cannot control the action.

In the case of radium, this decay would continue indefinitely until the radioactive material was ultimately converted to lead. For instance, in 1,590 years, half a gram of radium would transform into atoms with a lower atomic weight. Half of the remaining radium would transform after an additional 1,590 years, and so on until all of it turned into lead.

Attachment #1:

This is a revigator. It is a pot that was created specifically with radium, uranium, and other radioactive materials to contain water. When radioactivity was first discovered in 1912, people thought it was beneficial and "magical," similar to how homeopathic treatments are now. They would store water in it to allow it to absorb radiation, then they would drink the water. In the 1930s, several gadgets were subsequently recalled.

The enigmatic new radioactive elements captivated people's curiosity during the early 1900s. Although this starch didn't actually contain radium, it was given that name because of the rarity and beauty of radium. It was once thought of similarly to how titanium is now.

Madame Curie and her husband, Pierre Curie, made the discovery of radium. They were processing a ton of pitchblende, an ore that contains uranium. Although they were aware that the uranium was emitting invisible rays, they had the impression that there was another another, far more potent chemical present. They initially discovered polonium, another radioactive element, before successfully isolating a minute particle of radium.

The three types of rays that radium emits are alpha, beta, and gamma rays. Helium gas contains swiftly moving particles called alpha rays. In beta rays, the electrons move quickly. Gamma rays are similar to X-rays but typically more invasive. Every time one of these rays is emitted, its parent atom transforms into a different element. "Atomic transmutation" is the term for this transformation.

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>> ROR

Radiopaque refers to a White or light appearance of a structure on a processed radiograph. Radiolucent refers to a Dark appearance of a structure on a processed radiograph.

Materials that prevent electromagnetic radiation from passing through are referred to as radiodense or radiopaque, whereas materials that permit radiation to pass more readily are referred to as radiolucent. In contrast to radiolucent volumes, which appear significantly darker on radiographs, radiopaque volumes of material seem white.

It is the relative inability of radio waves and X-rays to flow through a certain substance. Radiodensity (or radiopacity) is opacity to the radio wave and X-ray portion of the electromagnetic spectrum.

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The renewable energies are the substitute for fossil fuel depletion has been heralded as the solution to the nation’s energy problems.

The benefits of renewable energies to the environment and economic are as follows.

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The new volume occupied by the gas is 1.2 m³.

Here Boyle's law is applied.

At a constant temperature, the volume of a gas is inversely proportional to the pressure exerted on it.

                                    PV = constant

where,

P = Pressure applied

V = Volume of the gas

Given,

P₁ = 5.0 atm

V₁ = 0.60 m³

P₂ = 2.5 atm

To find

V₂ =?

As PV = constant

Therefore,

P₁ V₁ = P₂ V₂

5 × 0.6 = 2.5 × V₂

3 = 2.5 × V₂

V₂ = 3/2.5

V₂ = 1.2 m³

Hence, the new volume occupied by the gas is 1.2 m³.

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When the hydrogen chloride concentration doubles, the number of collisions between the reactants becomes increased, which causes the rate of the forward reaction to be faster.

The rate of a reaction is how fast a chemical reaction occurs i.e. the conversion of reactants to products.

The rate of a chemical reaction can be influenced by certain factors including the concentration of reactants.

The more the concentration of a reactant, the more the collision between the reactants and hence, the faster the reaction will proceed.

Therefore, when the hydrogen chloride concentration doubles, the number of collisions between the reactants becomes increased, which causes the rate of the forward reaction to be faster

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Answer:1. increases 2. increases

Explanation:

Got it right on plato!

B. The chemical reaction that represents oxidation - reduction reaction is CaCO3(s) → CaO(s) + CO2(g).

In oxidation reduction reaction, the oxidizing agent is reduced while reducing agent is oxidized.

CaCO3(s) → CaO(s) + CO2(g)

Calcium (ca) is oxidized calcium (II) ion while the carbon (IV) oxide is reduced carbon (IV) oxide.

Thus, the chemical reaction that represents oxidation - reduction reaction is CaCO3(s) → CaO(s) + CO2(g).

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Answer: The answer is B

Explanation: on edge

94.1 mL of 10x PBS should be needed

Given:

Phosphate buffer solution = 10x

Volume of 1x solution of PBS = 941 mL

To Find:

Volume of stock solution

Solution:

A buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is added to it.

using the formula

M1 x V1 = M2 x V2

(10x)* V1 = 1x* 941

V1 = 94.1 ml

So, 94.1 mL of 10x PBS should be needed

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The new volume if the balloon is cooled at constant pressure is  3.98 L.

Charles's law, states that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature if the pressure remains constant.

The new  volume is calculated using the Charles law formula

                                 V₁ / T₁  = V₂ / T₂

where,

V₁ = The initial volume of air = 4.24 l

T₁ = 23.00 °C into kelvin = 23  +273 =296 K

T₂ = 5.00 °C into kelvin = 5.00 + 273 = 278 K

V₂ = ?

By making  V₂ subject the subject of the formula  by multiplying both sides by T₂

V₂ = ( V₁  × T₂ ) / T₁

V₂ =  (4.24 L  ×  278 K)  / 296 k  

   = 3.98 L

Therefore, the new volume, if the balloon is cooled at constant pressure, is  3.98 L.

An air-filled balloon will contract when chilled and expand when heated. This occurs because the gas that makes up the air within the balloon expands when it is warm and contracts when it is cool.

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Answer: at 5 its ... 3.98

Explanation:

Considering the definition of percentage by mass, the concentration of a solution if 15 g of salt is added to 170 g of water is 8.108 %.

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

In this case, you know:

Replacing in the definition of percentage by mass:

[tex]percentage by mass=\frac{15 grams}{185 grams}x100[/tex]

Solving:

percent by mass= 8.108 %

Finally, the concentration of a solution if 15 g of salt is added to 170 g of water is 8.108 %.

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the strength of the solution formed is 3.8.

The amount of solute dissolved in grammes per litre of the solution is used to determine the solution's strength. It stands for the solution's potency or concentration. It uses grammes per litre of expression.

Concentration of NaOH = 19 M

Initial volume of NaOH = 25 mL= 0.025 L

Moles of NaOH = 19*0.025

                        = 0.475 moles

Final volume of NaOH solution = 5 L

Final concentration = 0.475/5

                              = 0.095 M

so, the strength is 19/5

                            = 3.8

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Answer:

Explanation:

b

The mass of oxygen collected from the thermal decomposition of potassium chlorate at a temperature of 297 K and 762 mmHg is 0.16 g

We'll begin by obtaining the number of mole of oxygen gas produced from the reaction. This can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

739.6 × 0.128 = n × 62.363 × 297

Divide both sides by 62.363 × 297

n = (739.6 × 0.128) / (62.363 × 297)

n = 0.0051 mole

Thus, the number of mole of oxygen gas produced is 0.0051 mole

Haven obtain the number of mole of oxygen gas produced, we can determine the mass of the oxygen produced as follow:'

Mole = mass / molar mass

0.0051 = mass of oxygen / 32

Cross multiply

Mass of oxygen = 0.0051 × 32

Mass of oxygen = 0.16 g

Thus, we can conclude that the mass of oxygen gas collected is 0.16 g

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The 3 elements of a transaction that can be reclassified are:

On an account transaction screen, one can see there are different elements that exist and some of them are:

This refers to the proof that exists that a person has bought a good or service and can also stand as an agreement.

Hence, we can see that On an account transaction screen, one can see there are different elements that exist and some of them are:

However, there are only 3 elements that can be reclassified on the  reclassify transactions screen and they are:

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Answer:

Explanation:

stoichiometry of C₂H₂ to H₂O is 2:2.

Number of moles of C₂H₂ = molar mass of C₂H₂  

Since the molar mass of C₂H₂  is 26 g/mol.

Number of C₂H₂  moles reacted = 64.0 g / 26 g/mol = 2.46 mol.

according to a molar ratio of 2:2.

the number of H₂O moles formed = a number of C₂H₂  moles reacted.

Therefore the number of H₂O moles produced = 2.46 mol

Answer:

2 FeCl3 → 2 Fe + 3 Cl2

Explanation:

2 Fe and 6 Cl on the reactants side, and 2 Fe and 6 Cl on the products side.

The volume of 30% concentrated lime juice that must be added to a 4L solution of 80% concentrated lime juice and 20% water is 6 L.

Mixtures are substances which are formed when two or more substances are physically combined together.

Mixtures are heterogenous in nature and the constituents can be easily separated.

The volume of 30% concentrated lime juice that must be added to a 4L solution of 80% concentrated lime juice and 20% water, so that the concentration of the resulting solution is 50% concentrated lime juice is determined as follows:

Let the volume of 30% lime juice required be x;

total volume of lime juice = 0.3x

For 80% lime juice, volume of lime juice = 0.8 * 4 = 3.2 L

New volume of lime juice = 4 + x

New amount of lime juice added = 3.2 + 0.3x

Also, new amount of lime juice = 0.5 * ( 4 + x)

3.2 + 0.3x = 0.5 * ( 4 + x)

0.2x = 1.2

x = 6 L

In conclusion, the volume to be added is obtained from the percent concentration.

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The mass of benzoic acid is 0.244 g.

Here use the concept of molarity.

The amount of a substance in a specific volume of solution is known as its molarity (M). The moles of a solute per liter of a solution is known as molarity.

                            Molarity = no. of moles/volume (in L)

Given,

Molarity, M = 0.100 M

Volume, V = 20.00 mL = 20.0 × 10⁻³

To calculate,

Mass of benzoic acid C₇H₆O₂ =?

We know that,

Molecular mass of benzoic acid, C₇H₆O₂  = 122

No. of moles = weight/ molecular mass

The formula is modified as,

Molarity = weight of cholesterol/ (molecular mass) (Volume)

Put the values in the formula,

0.100 = Mass of benzoic acid/ (122) (20 × 10⁻³)

Mass of benzoic acid = 0.100 (122)(20 × 10⁻³)

                                    = 244 × 10⁻³

                                    = 0.244 g

Hence, the mass of benzoic acid is 0.244 g.

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Answer:

high

Explanation:

The energy needed to ionize a neutral atom is known as ionization energy. An atom must have one or more electrons removed from its valence shell in order to get ionized and become a cation. Alternately, you must produce an anion by adding one or more electrons to the valence shell. The energy needed for ionization will be lower the fewer electrons are supplied or withdrawn. As a result, atoms having an incomplete valence shell have a tendency to ionize more quickly and with less energy. However, entire valence shell atoms will require a large amount of ionization energy. As a result, noble gases need significant energy to ionize since they contain a full valence shell, are extremely stable, and do not tend to ionize easily.

the pressure in the balloon decreases- True

the pressure in the balloon increases- False

the volume of the balloon increases- True

the volume of the balloon decreases- False

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To determine how stable the beads are as well ensue the securing of maximum enzymes as well as the retention of their activity.

The concentration of a substance simply means the amount of the substance in solution. Thus we are looking at the amounts of sodium alginate and CaCl2 in the system.

The concentrations of the sodium alginate and CaCl2 is varied in order to determine how stable the beads are as well ensue the securing of maximum enzymes as well as the retention of their activity.

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Tempering Valve should be installed to cool the water.

A tempering valve is also called an anti-scald valve.

The thermostat controls the temperature inside the tank between 120F to 140F.

A thermostat is just a switch that is actuated by temperature. The thermostat will activates one of the elements in response to a "request for heat" when it detects a water temperature below its predetermined point.

At 140 degrees F temperature water can cause a burn to the skin in five seconds.

The Tempering valve is the mixing chamber, where cold water is mixed with hot water.  

It functions as a mixing device, mixing hot and cold water to generate the proper water temperature that is emitted from a certain outlet.

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Answer:

6.21 x 10¹⁴ Hz

Explanation:

The frequency can be found using the following equation:

λ = c / f

In this equation,

-----> λ = wavelength (m)

-----> c = speed of light (3.0 x 10⁸ m/s)

-----> f = frequency (Hz)

After converting the wavelength from nm to m, you can plug the given values into the equation and simplify to find the frequency.

 483 nm                 1 m
---------------  x  ---------------------  =  4.83 x 10⁻⁷ m
                          1 x 10⁹ nm

λ = c / f                                                         <----- Given equation

4.83 x 10⁻⁷ m = 3.0 x 10⁸ m/s / f                 <----- Insert values

(4.83 x 10⁻⁷ m) x f = 3.0 x 10⁸ m/s              <----- Multiply both sides by f

f = 6.21 x 10¹⁴ Hz                                       <----- Divide both sides by 4.83 x 10⁻⁷

The halogen or halogen-containing compound is typically used as a form of topical antisepsis will be "iodophor".

Iodine will be employed as an antiseptic in the manner of a tincture of iodine, essentially an alcoholic solution.

Iodophor would be an iodine-containing solution that also contains a solubilizing agent, like povidone or a surfactant. Iodophor would be a common sanitizer in the dairy but also brewing sectors. Generally, a high molecular weight carrier, commonly a polymer, has been polymerized with iodine.

Therefore, the halogen or halogen-containing compound is typically used as a form of topical antisepsis will be "iodophor".

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A first-order reaction is 81omplete in 264s.The half-life for this reaction (i) t 1/2 = =3.465×10 −3 s.to reach 95% Completion = 285 s.

To measure reaction rates, chemists initiate the reaction, measure the concentration of the reactant or product at different times as the reaction progresses,

For a 0-order response, the mathematical expression that may be employed to determine the half of life is: t1/2 = [R]0/2k. For a first-order reaction, the half of-existence is given by: t1/2 = zero.693/ok. For a 2d-order response, the method for the half-life of the response is: 1/okay[R]0

The 1/2-life of a response (t1/2), is the quantity of time needed for a reactant concentration to lower via half of compared to its initial awareness. Its software is used in chemistry and medicine to are expecting the awareness of a substance over time

Half of the lifestyles is the time required for exactly 1/2 of the entities to decay   50%.

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[tex]\\ \rm\dashrightarrow \Delta T_f=ik_fm[/tex]

Moles of NaCl

Molality

[tex]\\ \rm\dashrightarrow \Delta T_f=i(-1.86)(8.68)[/tex]

[tex]\\ \rm\dashrightarrow \Delta T_f=-16.14i[/tex]

i is vant Hoff factor

For NaCl vant Hoff factor is 2( Actually 1.9)

[tex]\\ \rm\dashrightarrow \Delta T_f=-16.14(2)=-32.28°C[/tex]

Moles of NaCl

[tex]\\ \tt{:}\dashrightarrow \dfrac{1000g}{23g/mol}[/tex]

[tex]\\ \tt{:}\dashrightarrow 43.4mol[/tex]

Find Molality

[tex]\boxed{\sf Molality=\dfrac{Moles\:of\:solute}{Volume \:of\: solution\:in\:kg}}[/tex]

[tex]\\ \tt{:}\dashrightarrow m=\dfrac{43.4}{6}=7.2m[/tex]

Vant Hoff factor

[tex]\\ \tt{:}\dashrightarrow NaCl\longrightarrow Na^++Cl^-[/tex]

Freezing point depression

[tex]\\ \tt{:}\dashrightarrow \Delta T_f=iK_fm[/tex]

[tex]\\ \tt{:}\dashrightarrow \Delta T_f=2(-1.86)(7.2)[/tex]

[tex]\\ \tt{:}\dashrightarrow \Delta T_f=-26.7°C[/tex]

a. 1s 2s 2p 3s 3p 4s 3d 4p is the correct option.

This gives the following order to fill the orbit: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, (8s, 5g, 6f, 7d, 8p, and 9s)

Aufbau's principle states that electrons fill low-energy atomic orbitals before they fill high-energy atomic orbitals. .. By following this rule, you can predict the electron configuration of an atom or ion.

There may be two electrons at the maximum of one orbit. Since the s subplane has only one orbit, it can hold up to two electrons. The p subplane has three orbitals, so it can hold up to six electrons. The d-subplane has five orbitals, so it can hold up to 10 electrons.

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