For a laboratory exercise in class, a student is given a mixture of small pieces of iron, sand, water, and salt. what physical property could be used to best separate the iron from the other ingredients?
a. Solubility
b. Magnetism
c. Melting Point
d. Electrical Conductivity

When Lithium's valence electron jumps to energy level n=4, it absorbs light at 486 nm. The wavelength of light that would be absorbed if the electron jumped to energy level n=3 instead is approximately 656 nm.

When a Lithium atom's valence electron jumps from its ground state (n=2) to higher energy levels, it absorbs light at specific wavelengths. In your case, when the electron jumps to n=4, it absorbs light at 486 nm. To determine the wavelength absorbed when the electron jumps to n=3 instead, we'll use the Rydberg formula for hydrogen-like atoms:

1/λ = RZ²(1/n₁² - 1/n₂²)

Here, λ is the wavelength, R is the Rydberg constant (1.097 x 10⁷ m⁻¹), Z is the atomic number of Lithium (Z=3), n₁ is the initial energy level (n=2), and n₂ is the final energy level.

For the electron jumping to n=3, we'll plug in the values:

1/λ = (1.097 x 10⁷)(3²)(1/2² - 1/3²)

Solving for λ, we get:

λ ≈ 656 nm

So, when the Lithium's valence electron jumps to energy level n=3, it absorbs light at a wavelength of approximately 656 nm.

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Answer:

191 days =16,502, 400 seconds

Answer:

It can be separated by simple fractional method

Answer:

C₂H6

Explanation:

Among the given options, the formula A) C₂H6 represents a hydrocarbon (specifically, ethane). Option A

A hydrocarbon is a compound that consists of only carbon and hydrogen atoms. It is important to identify the formula that represents a hydrocarbon among the given options:

A) C₂H6: This formula represents ethane, which is a hydrocarbon. Ethane consists of two carbon atoms bonded together with single bonds and six hydrogen atoms.

B) C₂H5OH: This formula represents ethanol, which is not a hydrocarbon. Ethanol contains a hydroxyl group (-OH), indicating the presence of oxygen in addition to carbon and hydrogen atoms. It is an alcohol, not a hydrocarbon.

C) C₂H5Cl: This formula represents ethyl chloride, which is not a hydrocarbon. Ethyl chloride contains a chlorine atom (Cl) in addition to carbon and hydrogen atoms. It is a haloalkane, not a hydrocarbon.

D) C₂H6O: This formula represents ethanol, which, as mentioned before, is not a hydrocarbon. Ethanol contains an oxygen atom (O) in addition to carbon and hydrogen atoms. It is an alcohol, not a hydrocarbon.

Among the given options, the formula A) C₂H6 represents a hydrocarbon (specifically, ethane). It consists only of carbon and hydrogen atoms, making it a suitable representation of a hydrocarbon.

In summary, the formula C₂H6 (option A) represents a hydrocarbon, while the other options contain additional elements (oxygen or chlorine) that make them non-hydrocarbon compounds. Option A

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Answer:

B 2

Explanation:

I checked it and it’s right hope this helps!!

Answer:

Explanation:

2H2O = H2 + O2

this ain't balanced because the value of hydrogen are not the same.

Answer:

the covalent compound would be

SO2

Answer:

A polar covalent bond will have the electrons shifted more towards one side or the other; a nonpolar bond will have evenly distributed electrons.

Explanation:

  The basis for a polar bond is that the electrons are shared unevenly. Some elements are more electronegative than others; that is, they pull harder on the electrons and tend to have more electrons around them. Following the periodic trends, Fluorine is the most electronegative element, so it will likely have the most dense area of electrons in a molecule. All this means that in a polar molecule, the electrons will be spread out unevenly along the lengths of the bonds as some elements will pull on them more than others will.

  Nonpolar molecules do not have to worry about differences in electronegativity, and so the electron density will be pretty evenly distributed along the entire molecule.

Hope this helps! :)

Answer:

Endothermic.

Explanation:

Because the temperature decreased, the reaction is endothermic.

Endothermic reactions absorb heat from the surroundings. In this case, the dissolution of the ammonium nitrate absorbed heat from the surroundings (the water). Hence, the temperature of the solution decreased.

Answer: 1. 20.0 grams

2. 0.272 moles

3. B) Mass --> Moles --> Volume

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number \(6.023\times 10^{23}\) of particles.

To calculate the number of moles, we use the equation:

\(\text{Number of moles}=\frac{\text{Given molecules}}{\text{Avogadros number}}\) or

\(\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}\) or  

Putting in the values we get:

1. \(\text{Number of moles of} Cl_2=\frac{1.7\times 10^{23}}{6.023\times 10^{23}}=0.282moles\)

Mass of \(Cl_2=moles\times {\text {Molar mass}}=0.282mol\times 71g/mol=20.0g\)

2. \(\text{Number of moles of NaCl}=\frac{3.28\times 10^{23}}{2\times 6.023\times 10^{23}}=0.272moles\)

3. \(\text{Number of moles of water}=\frac{26g}{18g/mol}=1.44moles\)

Volume of water =\(moles\times {\text {Molar volume}}=1.44mol\times 22.4L/mol=32.4L\)

Answer:

Osmosis

Explanation:

Water is very essential for the body. When we drink water, our blood cells absorbs water from the body. This happen by a process called as osmosis process. Osmosis is type of diffusion process.

Water along with oxygen and carbon dioxide are some of the simple molecules that moves into the blood cell. Osmosis is the process by which water molecules passes into the cell bodies through its semi permeable membrane.    

Considering the two acids and bases involved, the reverse reaction is favored.

The term reversible reaction refers to a reaction that can go either forward or backwards depending on the conditions of the reaction.

We must recall that acetic acid is a weak acid hence the equilibrium position would always lie towards the left hand side of the equation. Hence considering the two acids and bases involved, the reverse reaction is favored.

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The third law of thermodynamics states that a perfect crystalline structure of a pure solid substance has zero entropy at a temperature of 0 K.

Entropy is a measure of disorder or randomness in a system, and as temperature decreases, the molecules in a solid slow down, becoming more ordered and less random. The third law implies that achieving absolute zero is impossible as it would require an infinite amount of time and energy to completely remove all disorder.

Additionally, the third law provides a reference point for measuring entropy and allows scientists to determine the entropy of a substance at any given temperature.

This law has many practical applications, including in the design of materials for use in extreme environments, such as high-temperature superconductors and spacecraft heat shields.

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CaCl₂+2AgNO₃⇒Ca(NO₃)₂+2AgCl

mole CaCl₂: 3.5 g : 111 g/mole = 0.032

mole AgNO₃: 6.39 g : 170 g/mole = 0.038

mole: coefficient

CaCl₂: 0.032 : 1 = 0.032

AgNO₃: 0.038 : 2 = 0.019

AgNO₃ smaller= limiting reactant, then CaCl₂ = excess reactant

Answer:

In chemistry the substance is usually measured using molecular mass and molar mass. They are very important concepts in chemistry. Expression of molar mass is grams per mole.

...

Molar mass:

Difference between Molar mass and Molecular mass

Measurement given to compounds, atoms or molecules Determined only in molecules

Explanation:

hope the answer was helpful

Answer:

281 K

Explanation:

From the question given above, the following data were obtained:

Initial volume (V₁) = 1180 mL

Initial temperature (T₁) = 417 K

Final volume (V₂) = 0.796 L

Final temperature (T₂) =?

Next, we shall convert 0.796 L to millilitres (mL). This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.796 L = 0.796 L × 1000 mL / 1 L

0.796 L = 796 mL

Finally, we shall determine the final temperature as follow:

Initial volume (V₁) = 1180 mL

Initial temperature (T₁) = 417 K

Final volume (V₂) = 796 mL

Final temperature (T₂) =?

V₁/T₁ = V₂/T₂

1180 / 417 = 796/T₂

Cross multiply

1180 × T₂ = 417 × 796

1180 × T₂ = 331932

Divide both side by 1180

T₂ = 331932 / 1180

T₂ = 281 K

Therefore, the final temperature of the of the gas is 281 K

Direct expansion systems require the vapour exiting the evaporator to be superheated to avoid liquid slugging, to improve the effectiveness of the evaporator and to maintain the stability of the compressor. (B) Forced draft and induced draft evaporators differ in the way air is introduced into them. (C) CClF2CF3 (also known as R12) is a chlorofluorocarbon refrigerant. (ii) Tetrafluoroethane (also known as R134a) is a hydrofluorocarbon refrigerant and H2O is not classified as a refrigerant. (D) The partial pressure of hydrogen in the evaporator is 1.6 mmHg.

(a) Direct expansion systems are those in which the refrigerant in the evaporator evaporates directly into the space to be cooled or frozen. The evaporator superheat is used to make sure that only vapor and no liquid is carried over into the suction line and compressor. Superheating is required for the following reasons :

(b) Forced draft and induced draft evaporators differ in the way air is introduced into them. In an induced draft evaporator, a fan or blower is positioned at the top of the evaporator, and air is drawn through the evaporator from the top. In a forced draft evaporator, air is propelled through the evaporator by a fan or blower that is located at the bottom of the evaporator. Forced draft evaporators are frequently used in direct expansion systems because they allow for better control of the air temperature. Because the air is directed upward through the evaporator and out of the top, an induced draft evaporator is less effective at keeping the air at a uniform temperature throughout the evaporator.

(c) (i) CClF2CF3 (also known as R12) is a chlorofluorocarbon refrigerant.

(ii) Tetrafluoroethane (also known as R134a) is a hydrofluorocarbon refrigerant.

(iii) H2O is not classified as a refrigerant.

(d) The function of hydrogen gas in an absorption refrigeration system (NH3/H2O/H2) is to increase the heat of reaction between ammonia and water.

The pressure of hydrogen gas in the evaporator of an absorption refrigeration system can be determined using the formula, Pa/Pb = (Ta/Tb)^(deltaS/R),

where Pa = partial pressure of hydrogen in the evaporator, Ta = evaporating temperature, Tb = condensing temperature, Pb = partial pressure of hydrogen in the absorber, deltaS = entropy change between the absorber and evaporator, R = gas constant.

Substituting the given values, Ta = −2.0 ∘C = 271 K ; Tb = 38.0 ∘C = 311 K ; Pb = atmospheric pressure = 1 atm ;

deltaS = 4.7 kJ/kg K ; R = 8.314 kJ/mol K

we get, Pa/1 atm = (271/311)^(4.7/8.314)

Pa = 0.021 atm or 1.6 mmHg

Therefore, the partial pressure of hydrogen in the evaporator is 1.6 mmHg.

Thus, Direct expansion systems require the vapour exiting the evaporator to be superheated to avoid liquid slugging, o improve the effectiveness of the evaporator and to maintain the stability of the compressor. (B) Forced draft and induced draft evaporators differ in the way air is introduced into them. (C) CClF2CF3 (also known as R12) is a chlorofluorocarbon refrigerant. (ii) Tetrafluoroethane (also known as R134a) is a hydrofluorocarbon refrigerant and H2O is not classified as a refrigerant. (D) The partial pressure of hydrogen in the evaporator is 1.6 mmHg.

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Antonio's assumption that the raised dots on the paper represent numbers and the numbers represent letters is a reasonable starting point for understanding how dotted paper works. It reflects a common misconception about Braille, a tactile writing and reading system used by individuals who are blind or visually impaired.

However, a more accurate understanding is Rafi's suggestion that the dots represent both numbers and letters. Braille is a tactile writing system that uses combinations of raised dots in specific cell patterns to represent letters, numbers, punctuation marks, and even musical notation. Each Braille cell consists of six dots, arranged in two columns of three dots each.

In Braille, different combinations of these six dots are used to represent different symbols. For example, the letter "A" is represented by a single dot in the upper left corner of a cell, while the letter "B" is represented by dots in the upper left and upper right corners, and so on. Similarly, numbers are represented using specific combinations of dots in cell patterns.

Ham's insight that the dots represent different symbols and each symbol represents a word is not entirely accurate. While Braille can convey words, it represents individual letters and uses them to form words, just like in written text. Each cell in Braille usually represents a single letter, number, or other symbol, not an entire word.

It is important for Antonio and his classmates to understand the importance of Braille and its unique role in facilitating literacy and communication for the visually impaired. When they realize that the raised dots on the paper represent letters and numbers, they can appreciate the complexity and efficiency of the Braille system, which allows blind individuals to read, write, and access information independently.

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Answer:

subtracting the total enthalpy of the reactants from that of the products

so the ans should be the first one

The mutated amino acid at position 229 is arginine (Arg), and its substitution can potentially disrupt the 3D structure and alter the function of the protein due to changes in side chain properties and interactions.

Structure of the Amino Acids:

The wild-type amino acid at position 229 is not specified, so the structure cannot be provided.

The mutated amino acid is arginine (Arg), which has a side chain containing a positively charged guanidinium group.

Importance of the Position:

The specific position 229 in the protein sequence may be functionally significant, such as being involved in protein-protein interactions, binding sites, catalytic activity, or structural stability.

Without detailed knowledge of the protein, its function, and its structural context, it is difficult to determine the exact importance of this specific position.

Effects of the Mutation on Structure and Function:

The substitution of an amino acid at position 229 from the original to arginine can have various effects on protein structure and function.

Arginine's larger and positively charged side chain may introduce steric clashes or alter electrostatic interactions within the protein structure.

The mutation can potentially disrupt local or global protein folding, stability, or conformational changes, affecting its overall 3D structure.

The functional consequences of the mutation depend on the specific role of the amino acid at position 229, which can include changes in protein-protein interactions, enzymatic activity, substrate binding, or signal transduction pathways.

It is crucial to analyze the protein's structural context, available experimental data, and computational modeling techniques to gain a more accurate understanding of the specific effects of the mutation on the protein's structure and function in the given context.

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Answer:

The answer is decomposition of stone during acid rain

Explanation:

The reason being is that decomposition is most likely a result of a chemical change.

Answer:

Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which increases the substance's temperature to the melting point.

The height of a ramp does not directly determine the strength of the frictional force between a book and an object.

The strength of the frictional force between a book and an object is not directly influenced by the height of a ramp. The nature of the surfaces in contact, the force forcing the surfaces together (normal force), and the coefficient of friction are some of the variables that affect the frictional force between two surfaces.

The coefficient of friction between the book and the object plays a major role in determining the strength of the frictional force.

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Answer:

See explanation below

Explanation:

To get this, we need to apply the general expression for half life decay:

N = N₀e(-λt)    (1)

Where:

N and N₀ would be the final and innitial quantities, in this case, masses.

t: time required to decay

λ: factor related to half life

From the above expression we need λ and t. To get λ we use the following expression:

λ = t₁₂/ln2   (2)

And we have the value of half life, so, replacing we have:

λ = 8.04 / ln2 = 11.6

Now, we can replace in (1) and then, solve for t:

0.75 = 40 exp(-11.6t)

0.75 / 40 = exp(-11.6t)

ln(0.01875) = -11.6t

-3.9766 = -11.6t

t = -3.9766 / -11.6

Answer:

please mark brainlest and it's  Procedure 1: One of the products was a gas that escaped into the air.

Procedure 2: A gas from the air reacted with one of the other reactants

Explanation:

the gas ca evaporate so it would'nt be a or c and b dosent make sense.

Answer: D

Explanation:

D - Decomposition of carbonates into oxide and carbon dioxide

A - Combustion reaction. Combustion of methane to form Carbon dioxide and water.

C - Reaction of reactive metal (Na) and water to form hydroxide.

B - No particular name of the reaction. Usually denoted as a synthesis redox reaction.

Answer:CaCO3  CaO + CO2

Explanation: just took it