Why is H2S called an analytical agent?​

The ΔHrxn for the neutralization reaction between aqueous NaOH and HCl is -994.6 kJ/mol HCl.

Given that A 100.0 mL sample of 0.255 M NaOH is mixed with a 100.0 mL sample of 0.200 M HCl in a coffee cup calorimeter.  Both solutions were initially at 20.00°C and the temperature of the resulting solution was recorded as 37.00°C.  

We are to determine the ΔHrxn (in units of kJ/mol HCl) for the neutralization reaction between aqueous NaOH and HCl.  The balanced chemical equation for the neutralization reaction between aqueous NaOH and HCl is

 NaOH (aq) + HCl (aq) → NaCl (aq) + H2O  

(l)First, we need to determine the limiting reactant. It is necessary to identify the limiting reactant in order to calculate the moles of HCl reacted in the reaction and use it to determine ΔHrxn.  

Limiting reagent is the reactant that will be completely used up first, stopping the reaction. The reactant that is not completely consumed is the excess reactant.

We can use the concept of Stoichiometry to identify the limiting reactant.  To determine the limiting reactant, we can use the following formula:  

Molarity (M) = moles of solute (mol) / liters of solution (L) For NaOH, molarity (M) = 0.255 M For HCl, molarity (M) = 0.200 M.

Let's calculate the moles of NaOH and HCl:

Moles of NaOH = Molarity (M) × Volume (L)Moles of NaOH = 0.255 M × 0.100 L = 0.0255 mol

Moles of HCl = Molarity (M) × Volume (L)

Moles of HCl = 0.200 M × 0.100 L = 0.0200 mol

As we can see, the number of moles of NaOH is more than the number of moles of HCl.   NaOH is present in excess, while HCl is limiting.

The amount of HCl determines how much NaOH reacts, so we will use the number of moles of HCl to determine ΔHrxn.Next, we can calculate the amount of heat absorbed by the reaction:

qrxn = – qcal where qrxn = heat absorbed by the reactionqcal

= heat released by the calorimeterqcal

= (mass of water + mass of calorimeter) × specific heat of water × ΔTqcal = (200.0 g + 50.0 g) × 4.184 J/g·°C × (37.00°C – 20.00°C)

= 19,892 J or 19.892 kJqrxn

= – 19.892 kJ  (because no heat is lost to the calorimeter or the surroundings)

Next, we can use the equation below to calculate ΔHrxn:ΔHrxn = qrxn / n ΔHrxn = -19.892 kJ / (0.0200 mol × (-1)) = 994.6 kJ/mol HCl (Negative sign indicates that the reaction is exothermic).

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Explanation:

products are Nacl + H20

Answer: Hund's Rule

Explanation: The phenomenon is hund's rule of multiplicity.

The ratio of coefficients when the chemical equation Al + HCl ->AlCl₃ + H₂ is  balanced is 2:6:2:3.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

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Answer: metal turn orange and weaker as it gets oxidised

Explanation:

6.02 x \(10^{20\) formula units of MgCl₂ is equal to 0.1 moles of MgCl₂.

To convert formula units of MgCl₂ to moles of MgCl₂, we need to use Avogadro's number, which relates the number of formula units to the number of moles.

Avogadro's number (NA) is approximately 6.022 x 10^23 formula units per mole.

Given that we have 6.02 x 10^20 formula units of MgCl₂, we can set up a conversion factor to convert to moles:

(6.02 x 10^20 formula units MgCl₂) * (1 mol MgCl₂ / (6.022 x 10^23 formula units MgCl₂))

The formula units of MgCl₂ cancel out, and we are left with moles of MgCl₂:

(6.02 x 10^20) * (1 mol / 6.022 x 10^23) = 0.1 mol

Therefore, 6.02 x 10^20 formula units of MgCl₂ is equal to 0.1 moles of MgCl₂.

It's important to note that this conversion assumes that each formula unit of MgCl₂ represents one mole of MgCl₂. This is based on the stoichiometry of the compound, where there is one mole of MgCl₂ for every one formula unit.

Additionally, this conversion is valid for any substance, not just MgCl₂, as long as you know the value of Avogadro's number and the number of formula units or particles you have.

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Answer:

B. Alleles

Explanation:

The largest effect on the population of trout in Wisconsin was caused by the introduction of non-native species into the ecosystem.

The introduction of non-native species into an ecosystem can cause a disruption in the food chain, leading to a decrease in the population of native species. In Wisconsin, the introduction of non-native species such as the brown trout and rainbow trout has had a significant impact on the population of native brook trout.

The non-native species compete with the native brook trout for food and habitat, which has led to a decrease in the brook trout population. This highlights the importance of preserving the natural balance of ecosystems and avoiding the introduction of non-native species.

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Answer:

A molecule made of two or more elements chemically combined is a compound.

A molecule made of two atoms of the same element is just that an element.

A molecule made of two ( or more) elements is a compound.

Explanation:

Answer:

I'm pretty sure its d.

Explanation:

because a gbular protein is a protein that is round in shape, and a fibrous is a long a thin shaped protein. Which those are two kinds of proteins.

Answer:

South China sea

Explanation:

To the west is the South China Sea, to the east the Philippine Sea and the Pacific Ocean, and to the south the Celebes Sea (or Sulawesi Sea).

Answer:

9.0 moles Ca(NO₃)₂

Explanation:

from definition of Molarity = moles of solute / volume of solution in liters

=> moles = Molarity x Volume(L) = 6.00 molar x 1.5 liters = 9.0 moles Ca(NO₃)₂

For this question we are going to use Gay-Lussac's Law, which is an experimental gas law that shows the relationship between temperature and pressure in a gas. The formula is:

P1/T1 = P2/T2

We have:

P1 = 97 kPa

T1 = 308 K, we need to use Kelvin

P2 = ?

T2 = 348 K

Now we add these values into the formula:

97/308 = P2/348

0.315 = P2/348

P2 = 109.6 kPa, this will be new pressure

The ph value of human saliva is between 6.2-7.6 with 6.7 being the average pH

ph value of human saliva is 7 and 6

Rough ER is connected to the nuclear membrane and is responsible for the synthesis and processing of proteins.

The rough endoplasmic reticulum (ER) is a network of membrane-bound sacs and tubules that is studded with ribosomes on its surface. These ribosomes are responsible for protein synthesis. The rough ER is connected to the nuclear membrane because it receives instructions for protein synthesis from the DNA in the nucleus. This connection allows for the efficient transfer of genetic information from the nucleus to the rough ER.

Once the ribosomes on the rough ER synthesize proteins, the rough ER is also involved in the processing and modification of these proteins. It helps in folding the newly synthesized proteins into their functional three-dimensional shapes and also adds various modifications such as glycosylation (the addition of sugar molecules) or signal sequences that target the proteins to specific locations within or outside the cell.

After processing, the proteins may be transported to other parts of the cell or exported to the cell membrane or extracellular space. The connection between the rough ER and the nuclear membrane ensures a coordinated flow of genetic information and protein synthesis, allowing the cell to efficiently carry out its functions.

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The amount of heat required to raise the temperature of 67 g of water from 25.7°C to 66°C is approximately equal to 40.3 kJ. Thus, the answer is option a) 40.3 kJ.

The amount of heat required to raise the temperature of a substance is given by the equation:

q = m * c * ΔT

Here, q is the amount of heat required to raise the temperature , m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature due to the heat supplied.

Substituting the given values in the equation, we get:

q = (67 g) * (4.184 J/g°C) * (66°C - 25.7°C)

q = 40,332 J

Converting this value to kilojoules we obtain:

q = 40.332 kJ = 40.3 kJ

Thus 40.3 kJ of heat energy is required to raise the temperature of  67g of water from 25.7 °C to 66° C.

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Answer:

Epipelagic zone

Explanation:

The Epipelagic zone is the upper most layer of the ocean. It is the layer which receives maximum sunlight, because of availability of sunlight and nutrients like fresh oxygen and atmospheric carbon dioxide, this zone is suitable for active photosynthesis activity.

The limiting reactant will be the one that produces fewer moles of BaSO4. The excess reactant will be the one that has moles left over after the reaction.

To determine the grams of BaSO4 produced and the limiting reactant, we need to compare the stoichiometry of the balanced chemical equation for the reaction between Ba(NO3)2 and Na2SO4, which is:

Ba(NO3)2 + Na2SO4 → BaSO4 + 2NaNO3

First, calculate the number of moles for each reactant:

Moles of Ba(NO3)2 = 200.0 g / molar mass of Ba(NO3)2

Moles of Na2SO4 = 100.0 g / molar mass of Na2SO4

Then, calculate the moles of BaSO4 formed by comparing the stoichiometric coefficients:

Moles of BaSO4 formed = Moles of Ba(NO3)2 (according to the stoichiometry ratio)

Next, calculate the grams of BaSO4 formed:

Grams of BaSO4 formed = Moles of BaSO4 formed × molar mass of BaSO4

To identify the limiting reactant, compare the moles of BaSO4 formed from each reactant. The reactant that produces fewer moles of BaSO4 is the limiting reactant.

To determine the excess reactant remaining, calculate the moles of excess reactant and then convert it to grams.

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The correct option is (d) To express very large or very small number.

What is the Scientific Notation?

Scientific notation is a way to present numbers that are too large or too small to be easily written in decimal form. The three components of  scientific notation are coefficient, base and exponent. The proper format to write a scientific notation is a x 10^b, where a is a number or decimal number and b is the power of 10 to make scientific notation equivalent to original number. When a number between 1 and 10 is multiplied by a power of 10 then the number is expressed in scientific notation. For example,  10000000 can be written as 10⁷, which is the scientific notation and the exponent is positive here. Similarly, for the negative exponent 0.000001 can be can be represented as 10-⁷.                             Hence, the scientific notation is used to express very large or very small numbers.

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Answer:

Arm 1, because muscles in shorter arms can exert more force on an object held in the hand.

Explanation:

"All matter is made of tiny particles called atoms" is considered a scientific theory. Therefore the correct option is (B)

A scientific theory is a well-substantiated explanation of a natural phenomenon that has been repeatedly tested and confirmed through observation, experimentation, and data analysis.

From the statements in the question above, we can see that Option (B)  is a well-established and widely accepted explanation of a natural phenomenon that has been extensively tested through observation and experimentation.

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Answer:

18.015

Explanation:

Using the periodic table of the elements to find atomic weights, we find that hydrogen has an atomic weight of 1, and oxygen's is 16. In order to calculate the molecular weight of one water molecule, we add the contributions from each atom; that is, 2(1) + 1(16) = 18 grams/mole.

Answer:

The correct answer is chemical change because both a color change and a solid formation were observed, which provide strong evidence of a new substance.

A physical change is a change in the state of a substance, such as a change from a solid to a liquid or a change from a liquid to a gas. A chemical change is a change in the composition of a substance, such as the formation of a new substance.

When potassium iodide and lead nitrate are mixed, a yellow precipitate forms. This precipitate is a new substance that was not present before the two substances were mixed. Therefore, the change that occurs when potassium iodide and lead nitrate are mixed is a chemical change.

The other answers are incorrect.

* Answer 1 is incorrect because the observation of a solid forming is not evidence of a state change. A state change is a change in the physical state of a substance, such as a change from a solid to a liquid or a change from a liquid to a gas. The formation of a precipitate is not a state change, but rather a chemical change.

* Answer 2 is incorrect because the color change of the mixture is evidence of a chemical change. When two substances are mixed and a new substance is formed, the new substance may have a different color than the original substances.

* Answer 3 is incorrect because the statement "two substances were mixed, which always results in the formation of a new substance" is not always true. For example, if you mix two different types of liquids, you may not get a new substance. Instead, you may just get a mixture of the two liquids.

The reaction between potassium iodide and lead nitrate results in a chemical change because a color change and solid formation, indicative of a new substance, are observed.

When potassium iodide and lead nitrate are mixed, there is a chemical change that takes place. This is because both a color change and a solid formation were observed, which provide strong evidence of a new substance. In this reaction, two new compounds are formed - lead iodide and potassium nitrate - which is a clear indication of a chemical change. This process is not easily reversible, further supporting it being a chemical change.

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Ce clasă ești sa văd daca te pot ajuta

At equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

1: Write the balanced chemical equation:

\(C_O\)(g) + \(Cl_2\)(g) ⟶ \(C_OCl_2\)(g)

2: Set up an ICE table to track the changes in moles of the substances involved in the reaction.

Initial:

\(C_O\)(g) = 0.3500 mol

\(Cl_2\)(g) = 0.05500 mol

\(C_OCl_2\)(g) = 0 mol

Change:

\(C_O\)(g) = -x

\(Cl_2\)(g) = -x

\(C_OCl_2\)(g) = +x

Equilibrium:

\(C_O\)(g) = 0.3500 - x mol

\(Cl_2\)(g) = 0.05500 - x mol

\(C_OCl_2\)(g) = x mol

3: Write the expression for the equilibrium constant (Kc) using the concentrations of the species involved:

Kc = [\(C_OCl_2\)(g)] / [\(C_O\)(g)] * [\(Cl_2\)(g)]

4: Substitute the given equilibrium constant (Kc) value into the expression:

1.2 x \(10^3\) = x / (0.3500 - x) * (0.05500 - x)

5: Solve the equation for x. Rearrange the equation to obtain a quadratic equation:

1.2 x \(10^3\) * (0.3500 - x) * (0.05500 - x) = x

6: Simplify and solve the quadratic equation. This can be done by multiplying out the terms, rearranging the equation to standard quadratic form, and then using the quadratic formula.

7: After solving the quadratic equation, you will find two possible values for x. However, since the number of moles cannot be negative, we discard the negative solution.

8: The positive value of x represents the number of moles of \(Cl_2\)(g) at equilibrium. Substitute the value of x into the expression for \(Cl_2\)(g):

\(Cl_2\)(g) = 0.05500 - x

9: Calculate the value of \(Cl_2\)(g) at equilibrium:

\(Cl_2\)(g) = 0.05500 - x

\(Cl_2\)(g) = 0.05500 - (positive value of x)

10: Calculate the final value of \(Cl_2\) (g) at equilibrium to get the answer.

Therefore, at equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

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First, let's convert 32.5 grams of calcium oxide (CaO) in moles, using its molar mass which is 56.08 g/mol:

In the chemical equation, you can see that 1 mole of CaO reacting, produces 1 mol of CaF2. The mole ratio between these two compounds is 1:1, so 0.579 moles of CaO is producing 0.579 moles of CaF2.

The final step is to convert 0.579 moles of CaF2 to grams using its molar mass which is 78.08 g/mol:

The answer is that 32.5 grams of calcium oxide (CaO) reacted, producing 45.2 grams of calcium fluoride (CaF2).

Answer:

1.6

Explanation:

it crashes out so it can go. more faster