Which enthalpy of the reaction of the following equations is the same as the enthalpy of formation?
Ni (s) + ½ O, (g) -> NiO (s)
CO (g) + ½ O2 (g) -> CO2 (g)
.
KOH (s) -> K+ (ag) + OH (ag)
2 H (g) + Se (s) -> HaSe (g)
2 Fe (s) + 3 Cla (g) -> 2 FeCl, (s)

Answer:

I hope this helps :)

Explanation:

Immunohistochemistry (IHC) is a powerful technique that exploits the specific binding between an antibody and antigen to detect and localize specific antigens in cells and tissue, most commonly detected and examined with the light microscope.Jan 1, 2020

Answer: Mg2⁺(g) + Se2⁻(g) → MgSe(s)

Explanation: This response includes the arrangement of one mole of MgSe(s) from its constituent vaporous particles, and the discharge of cross section vitality. The other responses recorded don't include the arrangement of MgSe from its constituent particles within the gas stage, so they are not related with the grid vitality of MgSe.

Three patterns that are true regarding seasons on Earth are: 1. Seasons are caused by the tilt of Earth's axis. 2. Seasons are opposite in the Northern and Southern Hemispheres. 3. Seasons are characterized by changes in temperature and weather patterns.

As Earth orbits around the sun, different parts of the planet receive varying amounts of sunlight depending on their angle to the sun.

When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere, and vice versa.

For example, summer is typically associated with warm temperatures, longer days, and increased humidity, while winter is associated with colder temperatures, shorter days, and often snow or rain.

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Answer:

CnH2n

Explanation:

Alkenes are either branched or unbranched hydrocarbons with at least one carbon–carbon double bond (CC) and have a general formula of CnH2n.

The thinner and denser layer labelled "2" in the diagram represents the marine crust, while the thicker and less dense layer labelled "1" represents the continental crust. Therefore, A. 1; 2 is the right response.

The land on Earth is made up of the continental crust, which is less dense, thicker (between 35 and 70 km), and primarily composed of the rock granite. The majority of the ocean is made up of oceanic crust, which is denser, thinner (5–7 km), and primarily composed of the rock basalt.

With a density of around 2.7 grammes per cubic cm, continental crust has a largely granitic composition and is slightly lighter than Oceanic crust has a density of roughly 2.9 to 3 grammes per cubic centimetre and is composed of basalt, which is richer in iron and magnesium than granite.

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To solve molality use the following equation: ΔTb = Kb x molality.

Molality (m) is a measure of the concentration of a solution and is defined as the number of moles of solute per kilogram of solvent. To calculate molality, follow these steps:

To find the boiling point of the solution (BP solutions), the boiling point elevation constant (Kb) of the solvent and the molality of the solution. With these values, we can use the following equation:

ΔTb = Kb x molality

where ΔTb is the boiling point elevation, Kb is the boiling point elevation constant of the solvent, and molality is the molal concentration of the solution.

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The data collected by Leah and Paul supports Paul's opinion that matter can exist even when it is not visible.

Support is a term used to describe a range of services and resources offered to individuals in need. It can refer to providing help with practical tasks, such as helping someone to manage their finances or providing transport to medical appointments. It can also refer to providing emotional or social support. This could involve providing counselling or having regular conversations to help someone to feel understood and supported. Support can also refer to offering advice and guidance, or providing a safe space for someone to talk and express their feelings. In its broadest sense, support is about helping someone to have the best quality of life they can.

This is because the mass of the inflated bag is greater than the mass of the empty bag despite the fact that the volume of the inflated bag is much greater. This shows that the inflated bag contains air, which is matter, even though it cannot be seen.

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Answer:

Temperature is a measure of the average kinetic energy of the particles in a substance. Therefore, the substance with the least thermal energy would be the one with the lowest temperature and the lowest mass.

Using this information, we can see that the substance with the least thermal energy is 10 g of metal at 10°C. This is because it has both a lower temperature and a lower mass than the other substances listed. The other substances have a higher temperature and/or a higher mass, which means they have more kinetic energy and therefore more thermal energy.

The number of moles of AgI that will be formed when 75.0 mL of 0.300 M AgNO₃ is completely reacted is 0.0225 moles.

The number of moles of a substance can be calculated from a stoichiometric approach.

Stoichiometry is the study and calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions (chemical equations).

According to this question, the following reaction is given: 2AgNO₃(aq) + Cal2(aq)-->2Agl(s) + Ca(NO3)2(aq)

moles of AgNO₃ = 0.075 × 0.3 = 0.0225 moles

If 2 moles of AgNO₃ reacted to produce 2 moles of AgI, then 0.0225 moles of AgI will also be produced.

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Show a greater conductivity than the covalent compound. This is because of the existence of strong electrostatic forces between the ions of the ionic compounds.

A force is an external agent capable of changing a body's state of rest or motion. It has a magnitude and a direction.A force is not something that an object contains or 'has in it'. A force is exerted on one object by another. The idea of a force is not limited to living things or non-living things.

it is formed by the loss or gain of an electron by an atom. Ions are of two types: cations and anions. For example, A sodium ion (Na+ ) is formed when a sodium atom loses one electron.

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Moles of HCL present in the reaction is 0.899 moles

The mole is the unit of substance that is equal to the number of atoms in 0.012 kilogrammes of carbon 12 and is represented by the sign "mol".

chemical reaction, the transformation of one or more chemicals (the reactants) into one or more distinct compounds (the products). Chemical elements or chemical compounds make up substances. In a chemical reaction, the atoms that make up the reactants are rearranged to produce various products.

Use the following formula to calculate the moles of each reactant present at the start of the reaction:

Molar mass divided by mass equals a mole.

The molar mass of HCl is 36.461 g/mol (1.008 g/mol for H and 35.453 g/mol for Cl), while the molar mass of [tex]Ca(OH)_2[/tex] is 74.093 g/mol (40.078 g/mol for Ca, plus 215.999 g/mol for O and 21.008 g/mol for H).

Consequently, the amount of [tex]Ca(OH)_2[/tex] in the starting moles of the reaction is:

[tex]Ca(OH)_2[/tex] moles are equal to 48.5 g / 74.093 g/mol, or 0.654 moles.

At the start of the reaction, there are: moles of HCl present.

32.8 g of HCl divided by 36.461 g/mol yields 0.899 moles.

Since we have only 0.899 moles of HCl present, it is the limiting reactant. This means that all of the [tex]Ca(OH)_2[/tex] will react, and some of the HCl will be left over.

To convert this to grams, we use the formula:

mass = moles x molar mass

The molar mass of [tex]CaCl_2[/tex] is 110.984 g/mol (40.078 g/mol for Ca and 2*35.453 g/mol for Cl).

Therefore, the mass of [tex]CaCl_2[/tex] produced is:

mass of [tex]CaCl_2[/tex] = 0.654 moles x 110.984 g/mol = 72.6 g

So, 48.5 g of [tex]Ca(OH)_2[/tex] and 32.8 g of HCl will produce 72.6 g of [tex]CaCl_2[/tex] and 2 moles of [tex]H_2O[/tex].

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Answer:

1.81 micromol/L.

Explanation:

The concentration of a solution is calculated by dividing the amount of solute by the volume of the solution. In this case, the amount of calcium sulfate is 0.181 micromol and the volume of the solution is 100 mL. So, the concentration of calcium sulfate in the solution is (0.181 micro mol) / (100 mL) = **1.81 micro mol/L

its e00 molew then asg hol

There are 0.2107 moles of KBr are dissolved in 60.2 mL of a 3.50 M solution.

The molarity of a substance is defined as the number of moles of solute present in 1 litre of a solution.

According to the given data, the molarity of the solution tells us that there are 3.50 moles of KBr in 1000mL of solution. But we only have 60.2mL of solution, so with a mathematical rule of three we can calculate the amount of moles in 60.2mL:

1000 ml - 3.50 moles

60.2 ml -x = 60.2 ml× 3.50 moles/1000 ml

x= 60.2 ml -0.2107 moles

So, there are 0.2107 moles of KBr.

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Please note that the actual pH values and corresponding labels may vary depending on the specific pH range of the acids and bases you are using in your experiment.

What is pH?

pH is a measure of the acidity or basicity of a solution. It is a scale that ranges from 0 to 14, with 7 being considered neutral. A pH value less than 7 indicates acidity, with lower values indicating higher acidity. A pH value greater than 7 indicates basicity, with higher values indicating higher basicity.

pH is a measure of the concentration of hydrogen ions (H+) in a solution. A lower pH value indicates a higher concentration of H+ ions, which makes the solution more acidic.

It's important to measure and record the actual pH values of the solutions in the test tubes to accurately determine their acidity or basicity.

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The acids and bases shown right cover a range of pH values. Use

what you know about acids, bases, and concentration to label the

test tubes, in order, from most acidic to most basic.

The mass of the percent of the 10 g solute in the 105 g solvent is 8.69 %.

The mass of the solute = 10 g

The mass of the solvent = 105 g

The mass of the solution = 10 g + 105 g

The mass of the solution = 115 g

The mass of the percent is expressed as :

The mass of percent = ( mass of solute / mass of solution ) × 100 %

The mass of solute = 10 g

The mass of solution = 115 g

The mass of percent = ( 10 / 115 ) × 100 %

The mass of percent = 8.69 %

Thus, the mass of percent is 8.69 % and the mass of solute is 10 and the mass of the solution is 115 g.

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Photosynthesis is the method by which plants produce their own food. Plants and other living things employ the process of photosynthesis to transform light into chemical energy that is then stored as starch that can be used at a later time. A vital step in plant growth is photosynthesis.

As autotrophs, plants produce their own sustenance. During the process of photosynthesis, they turn water, sunlight, and carbon dioxide into oxygen or simple sugars that the plant uses as fuel. These fundamental producers, which form the basis of an ecosystem, provide food for subsequent trophic levels.

Plants use the energy of a sun's light during the process of photosynthesis. Where the carbon dioxide and water are combined to create glucose, which the plants use as nourishment, using the trapped light energy to convert into chemical energy.

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The term that best classifies sodium chloride mixed in water at room temperature is a homogeneous mixture or solution.

~~~Harsha~~~

Answer:

It is homogeneous

Explanation:

The compound NH4Cl or ammonium chloride is composed of two ions: ammonium ion (NH4+) and chloride ion (Cl-). The ammonium ion is a polyatomic cation made up of one nitrogen atom and four hydrogen atoms, while the chloride ion is a monatomic anion made up of one chlorine atom.

a. Wax melts near the flame of a burning candle because the kinetic-molecular theory states that the higher the temperature, the faster the molecules move. Since the flame of a burning candle is hot, the wax molecules move faster, allowing them to take up more space and eventually melt.

The kinetic-molecular theory is based on the following five fundamental principles:

A gas's average molecular lengths between its constituent molecules are significantly greater than their individual sizes. The volume occupied by the gas' molecules is negligible in comparison to the volume of the gas itself.Both the molecules and the container walls are not attracted to one another in a perfect gas.As physical objects, the molecules move erratically and continually and are governed by Newton's laws of motion. The molecules travel in a straight line until they come into contact with one another or the container walls. Collisions are totally elastic; even if the kinetic energies and orientations of two molecules may change during a collision, the total kinetic energy is preserved. Collision is not "sticky".The average gas molecule's kinetic energy and absolute temperature are directly correlated. Because individual molecules' velocities and kinetic energies will vary greatly, with some even experiencing zero velocities at some moments, the word "average" is significant in this context. This implies that all molecular motion would cease if the temperature dropped to absolute zero.

b. Due to the fact that the kinetic-molecular theory predicts that molecules move more slowly at lower temperatures, liquid water can be frozen into ice cubes in a freezer. The water molecules travel very slowly and arrange because a freezer is significantly colder than room temperature, which enables them to form ice cubes.

c. All matter is made up of a large number of tiny particles that are always in motion, according to the kinetic-molecular theory. When the ginger ale is poured into the glass, the velocity of the liquid's molecules causes them to spread out and fill the form of the vessel.

d. The kinetic-molecular theory states that the molecules in a liquid are in constant motion, and that when they move, they bump into each other, passing energy from one to the other. This energy causes the particles to move faster. As they move faster, they create turbulence that causes them to break away from the liquid surface. These particles then form a vapor, which is an invisible form of water called water vapor. As these particles accumulate together, they gradually evaporate from the swimming pool, eventually diminishing its water level.

e. Water vapor condenses inside house windows on cold days because the molecules of water vapor slow down and as they lose energy they no longer have enough kinetic energy to remain in the gaseous state. The molecules then condense and form liquid water droplets on cool surfaces such as windows.

f. Snow gradually disappears even when the temperature remains below freezing because the heat stored in the snow starts to melt the snow. This occurs even when the outside temperature remains at freezing or below because the heat is released from the snow and warms the surrounding air.

g. Solids and liquids cannot be compressed as much as gases because the particles of gases have more energy and thus more freedom of movement than particles of solids and liquids. The particles of gases can move around and can occupy larger spaces than particles of solids and liquids, allowing them to be compressed more effectively.

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Answer: non-polar covalent

Explanation:

If two atoms have an electronegativity difference of 0.4 or less, they form a non-polar covalent bond.

B is 2.04 electronegativity

H is 2.20 electronegativity

the electronegativity difference is 0.16.

this is less than 0.4 so the bonds are non-polar covalent.

At 25°C, combine 47.0 mL of ethylene glycol (d = 1.11 g/mL; molar mass = 62.07 g/mol) with 50.0 mL of water (d = 1.00 g/mL) to create an antifreeze solution. The antifreeze solution's molarity is 0.0086 M if its density is 1.07 g/mL.

Antifreeze is an additive that reduces a water-based liquid's freezing point. To achieve freezing-point depression for cold conditions, an antifreeze combination is utilized. Common antifreezes also raise the liquid's boiling point, enabling a rise in coolant temperature. However, every typical antifreeze addition also has a lower heat capacity than water, which makes it less effective as a coolant when combined with water.

The combination of a solution's freezing and boiling temperatures depends on the amount of dissolved components present. Therefore, salts cause aqueous solutions' melting points to decrease. Although salts are widely used for de-icing, salt solutions should not be utilized in cooling systems as they cause metal corrosion. Because they typically have melting values that are lower than those of water, low molecular weight organic substances can be used as antifreeze. Alcoholic organic compound solutions, in particular, are useful. Since antifreezes were first made commercially available in the 1920s, they have all been composed primarily of alcohols such methanol, ethanol, ethylene glycol, and others.

Molarity = [tex]\frac{mole}{volume}[/tex]

To calculate the moles of ethylene glycol.

The mass of ethylene glycol is 47.0 mL × 1.11 g/mL = 52.17 g.

Since molar mass of ethylene glycol is 62.07 g/mol, the moles of ethylene glycol is:

[tex]\frac{52.17}{62.07}[/tex] = 0.84 mol

To calculate the total volume of the antifreeze solution. We know that the volumes of ethylene glycol and H₂O are 47.0 mL and 50.0 mL, respectively.

Therefore, the total volume of the antifreeze solution is 47.0 mL + 50.0 mL = 97.0 mL.

Finally, the molarity of the antifreeze solution can be calculated using the formula

Molarity = [tex]\frac{mole}{volume}[/tex]

Therefore, the molarity of the antifreeze solution is:

[tex]\frac{0.84}{97.0}[/tex] = 0.0086 M

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The correct answer is option A, [tex]NH_{4}^{+}[/tex]  which is an example of a Brønsted-Lowry acid.

Brønsted-Lowry acid:

According to the Brønsted-Lowry theory, an acid is a substance that donates a proton ([tex]H^{+}[/tex]), while a base is a substance that accepts a proton.

[tex]NH_{4}^{+}[/tex]can act as an acid because it can donate a proton to a base. In this case, [tex]NH_{4}^{+}[/tex]can donate a proton to a water molecule, forming [tex]NH_{3}[/tex] an H3O+. Therefore, [tex]NH_{4}^{+}[/tex]is an example of a Brønsted-Lowry acid.

Option B, F, is a Brønsted-Lowry base because it can accept a proton to form HF. Option C, [tex]BF_{3}[/tex], is not an acid or a base according to the Brønsted-Lowry theory because it does not contain any hydrogen atoms that can donate protons. Option D, [tex]NH_{3}[/tex], is a Brønsted-Lowry base because it can accept a proton to form [tex]NH_{4}^{+}[/tex].

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Complete question is:  [tex]NH_{4}^{+}[/tex] is an example of a Brønsted-Lowry acid.

The pressure in the vessel is 3.76 atm.

To find the pressure in the vessel, we can use the ideal gas law, which states:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature in Kelvin.

First, we need to calculate the total number of moles of gas in the vessel:

n(total) = n(N₂) + n(H₂) + n(Ar)

We can find the number of moles of each gas using the formula:

n = m/M

where m is the mass of the gas and M is the molar mass of the gas.

n(N₂) = 2.80 g / 28.01 g/mol = 0.0999 mol

n(H₂) = 0.807 g / 2.02 g/mol = 0.400 mol

n(Ar) = 79.9 g / 39.95 g/mol = 2.00 mol

n(total) = 0.0999 mol + 0.400 mol + 2.00 mol = 2.50 mol

Next, we can convert the temperature from Celsius to Kelvin:

T = 25°C + 273.15 = 298.15 K

Finally, we can plug in the values into the ideal gas law:

PV = nRT

P(18.9 L) = (2.50 mol)(0.08206 L·atm/mol·K)(298.15 K)

P = (2.50 mol)(0.08206 L·atm/mol·K)(298.15 K) / (18.9 L)

P = 3.76 atm

Therefore, the pressure in the vessel is 3.76 atm.

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26.71 g mass of tin would be required to completely react with 1.20 L of 0.750 M HBr.

What is mass ?

Mass is a measure of the amount of matter in an object or substance. It is often expressed in units of grams (g) or kilograms (kg). Mass is a fundamental property of matter and is different from weight, which is the force exerted on an object by gravity and varies depending on the object's location. Mass can be measured using a balance or scale, and is an important factor in many chemical calculations and experiments, such as determining the amount of reactants needed for a reaction or the concentration of a solution.

First, we need to determine the number of moles of HBr in the solution:

moles of HBr = Molarity x Volume

moles of HBr = 0.750 mol/L x 1.20 L

moles of HBr = 0.900 mol

According to the balanced chemical equation, 1 mole of Sn reacts with 4 moles of HBr to produce 1 mole of SnBr₄. Therefore, the number of moles of Sn required can be calculated as:

moles of Sn = (moles of HBr) / 4

moles of Sn = 0.900 mol / 4

moles of Sn = 0.225 mol

The molar mass of Sn is 118.71 g/mol, so the mass of Sn required can be calculated as:

mass of Sn = moles of Sn x molar mass of Sn

mass of Sn = 0.225 mol x 118.71 g/mol

mass of Sn = 26.71 g

Therefore, 26.71 g of tin would be required to completely react with 1.20 L of 0.750 M HBr.

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Complete question is:  26.71 g mass in grams of tin would be required to completely react with 1.20 L of 0.750 M HBr in the chemical reaction. Sn(s) + 4 HBr(aq) → SnBr₄ (aq) + 2 H₂ (g)

If the density of antifreeze solution is 1.07 g/mL, then the molarity of the antifreeze solution is calculated as 8.66 M.

Number of moles of solute dissolved per liter of the solution is defined as molarity.

As we know, moles of EG = mass of EG / molar mass of EG

Mass of EG = 47.0 mL × 1.11 g/mL = 52.17 g

Moles of EG = 52.17 g / 62.07 g/mol = 0.840 mol

Total volume = 47.0 mL + 50.0 mL = 97.0 mL

So, mass of solution = volume of solution × density of solution

mass of solution = 97.0 mL × 1.07 g/mL = 103.79 g

As, molarity =moles of solute /volume of solution

Molarity = 0.840 mol / (97.0 mL / 1000 mL/L) = 8.66 M

Therefore, the molarity of the antifreeze solution is 8.66 M.

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