Which of these is the best and most reliable proof of a chemical change? question 5 options: a change of state occurs. heat is released into the air. a change of color occurs. a new substance is produced.

The number of moles of sodium chloride (NaCl) that can be produced is:

4.5 moles Na * (2 moles NaCl / 2 moles Na) = 4.5 moles NaCl from 4.5 moles of sodium (Na), you can produce 4.5 moles of sodium chloride (NaCl) according to the balanced chemical equation.

The balanced chemical equation shows that 2 moles of sodium (2Na) react with 1 mole of chlorine (Cl₂) to produce 2 moles of sodium chloride (2NaCl). From the given information, we have 4.5 moles of sodium (Na). According to the stoichiometry of the balanced equation, we can determine the number of moles of sodium chloride (NaCl) that can be produced by using a simple mole ratio. Mole ratio of Na to NaCl: 2 moles NaCl / 2 moles Na Therefore, the number of moles of sodium chloride (NaCl) that can be produced is: 4.5 moles Na * (2 moles NaCl / 2 moles Na) = 4.5 moles NaCl Hence, from 4.5 moles of sodium (Na), you can produce 4.5 moles of sodium chloride (NaCl) according to the balanced chemical equation.

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10.9 g of water are required to form 75.9 g of HNO3 for the balanced reaction for the solution.

The concentration of sodium bromide can be calculated using the formula:
Concentration (mM) = (mass of solute in grams / molar mass of solute in g/mol) / (volume of solution in liters) * 1000

First, we need to convert the volume of solution from mL to liters:
125 mL = 0.125 L

Next, we can plug in the values:
Concentration (mM) = (3.50 g / 102.89 g/mol) / 0.125 L * 1000

Concentration (mM) = 272 mM

Therefore, the concentration of sodium bromide is 272 mM.

For the second question, we can use stoichiometry to calculate the amount of water required. The balanced equation tells us that 1 mole of H2O reacts with 2 moles of HNO3. We can use the molar mass of HNO3 to convert the given mass to moles, and then use the stoichiometric ratio to calculate the moles of H2O required.

First, we convert the given mass of HNO3 to moles:

75.9 g / 63.02 g/mol = 1.205 mol HNO3

Next, we use the stoichiometric ratio to find the moles of H2O required:
1.205 mol HNO3 / 2 mol HNO3 per 1 mol H2O = 0.6025 mol H2O

Finally, we convert the moles of H2O to grams using the molar mass:
0.6025 mol H2O * 18.02 g/mol = 10.86 g H2O

Therefore, 10.9 g of water are required to form 75.9 g of HNO3.

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Answer:

neutrons in c,o,b,h

Explanation:

i think so

Answer:

6860

Explanation:

The existence of isotopes violates one of the original ideas of Dalton's atomic theory that is  listed below:

1.An element consists of only one type of atom, which has a mass that is characteristic of the element and is the same for all atoms of that element.

2.Atoms of one element differs in properties from atoms of all the  other elements.

Dalton initially believed that every atom of a specific element had the same characteristics, including mass. As a result, the idea of isotopes—in which an element has various masses—violated the original principle. The second postulate of his atomic theory was changed to require that atoms of the same element have the same chemical characteristics in order to account for the occurrence of isotopes.

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Answer: 1.valving  , 2. picking, 3. decantation , 4. sorting, 5. seiveing

Thank me later!

The theoretical weight of sodium borohydride is  1900 g

Now we know that the theoretical weight is the weight that is obtained from the stoichiometry of the reaction. Now we are given that the number of moles of the benzil is 50 moles and the reaction is 1:1.

1 mole of benzil reacts with 1 mole of sodium borohydride

50 moles of benzil reacts with 50 moles of sodium borohydride

Thus;

Mass of sodium borohydride = 50 moles * 38 g/mol

= 1900 g of sodium borohydride

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Answer:

4.5M

Explanation:

Here is why:

I actually do not know the answer can I help tommorow if you are fine with it tooo sleeeepy have 14 exams tommorow have to prepare.

Sorry:(

Answer:

B) It is not balanced for oxidation state or for number of atoms

Explanation:

I got this question correct on my Edge quiz, so I know that this is the right answer.

The reactant side has 2 oxygen atoms, while the product side only has 1. This means the mass isn't balenced. In addition, the oxidation (charge) on the reactant side is 0, while it's -2 on the product side. This means the oxidation nor mass is balenced.

Hope that helps you!

Answer:

b

Explanation:

A major problem that is thwarting efforts to clean up the air is: b. Lack of routine air quality monitoring in developing nations.

Air pollution is rising, common and dangerous effect seen in current scenario. The excessive usage of harmful equipments like vehicles, air conditioners, refrigerators and others leads to contamination of environment.

The inhalation of toxic gases leads to lung disorders and other bodily issues. It also has harmful effect on environment and animals. The improper air cleaning frequency has further lead to no change in worst scenario of air pollution.

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Explanation:

HCl + __ => CuCl2 + H2O

The blank should be the metal, which is copper.

(This reaction is not spontaneous but can happen using electrolysis, etc.)

The pH at the half-stoichiometric point for the titration of 0.22 M HNO2(aq) with 0.01 M KOH(aq) is 3.37.

The titration reaction between HNO2 and KOH is:

HNO2(aq) + KOH(aq) → KNO2(aq) + H2O(l)

The balanced equation shows that 1 mole of KOH reacts with 1 mole of HNO2. At the half-stoichiometric point, half of the HNO2 has reacted with KOH, and the other half remains unreacted.

This means that the number of moles of HNO2 remaining in the solution is equal to the number of moles of KOH that have been added.

The initial concentration of HNO2 is 0.22 M, and the volume of KOH required to reach the half-stoichiometric point can be calculated using the equation:

n(KOH) = C(KOH) x V(KOH)

where n is the number of moles, C is the concentration, and V is the volume. At the half-stoichiometric point, n(HNO2) = n(KOH)/2. Substituting the values gives:

n(KOH)/2 = 0.22 M x V(KOH)

V(KOH) = n(KOH)/0.44 M

The total volume of the solution at the half-stoichiometric point is the sum of the volumes of HNO2 and KOH added. This can be calculated using the equation:

V(total) = V(HNO2) + V(KOH)

Substituting the values gives:

V(total) = V(KOH) + V(KOH)/0.22

V(total) = V(KOH)(1 + 1/0.22)

V(KOH) = V(total)/1.22

The concentration of OH- at the half-stoichiometric point can be calculated from the amount of KOH added:

C(OH-) = n(KOH)/V(total)

C(OH-) = 0.01 M x n(KOH)/(V(total))

Substituting the value of V(KOH) gives:

C(OH-) = 0.01 M x n(KOH)/(V(total)/1.22)

C(OH-) = 0.01 M x n(KOH)/(V(KOH) x 1.22)

The concentration of H+ can be calculated from the dissociation constant and the concentration of HNO2:

Ka = [H+][NO2-]/[HNO2]

[H+] = Ka x [HNO2]/[NO2-]

At the half-stoichiometric point, [NO2-] = [HNO2] = 0.11 M (half of the initial concentration). Substituting the values gives:

[H+] = 4.3 x 10^-4 x 0.11 M / 0.11 M

[H+] = 4.3 x 10^-4 M

The pH can be calculated from the concentration of H+ using the equation:

pH = -log[H+]

pH = -log(4.3 x 10^-4)

pH = 3.37

Therefore, the correct answer is option 4: 3.37.

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Answer:

Matching

6.D

7.A

8.C

9.B

Explanation:

Took test

103 °C, 90 °C, 101 °C Neither accurate nor precise, 100 °C, 99 °C, 100 °C are Precise, 105 °C, 106 °C, 105 °C are Both accurate and precise, 99 °C, 101 °C, 100 °C are Accurate. These are the correct set of measurements of the boiling point of water.

The melting point is defined as the temperature at which solid and liquid phases are at equilibrium state, whereas the boiling point is defined as the temperature at which the pressure of a vapor of a  liquid is equal to the external pressure.

Melting point in which the melting of solid occur to become a liquid at a given temperature, here the molecules gain enough amount of kinetic energy to get the intermolecular forces to convert into another form.

In case of Boiling point the liquid phase enters into the gaseous phase, when the external pressure is high than a temperature for the vapor pressure equal to the external pressure.

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To determine the number of moles of hydrogen needed to crack one mole of the long saturated hydrocarbon chain (C40H82), we can analyze the reactants and products involved in the cracking reaction.

The cracking reaction is given as: C40H82 -> 3 C8H18 + n C2H6. From the equation, we can see that one mole of the long hydrocarbon chain (C40H82) produces three moles of octane (C8H18) and n moles of ethane (C2H6). Since the cracking process involves breaking the carbon-carbon bonds and forming new carbon-hydrogen bonds, the number of hydrogen atoms in the products should remain the same as in the reactant.

The long hydrocarbon chain (C40H82) contains 82 hydrogen atoms, and the products, 3 moles of octane (C8H18), contain (3 moles) * (18 hydrogen atoms/mole) = 54 hydrogen atoms. Therefore, the number of moles of hydrogen needed for cracking one mole of the long hydrocarbon chain can be calculated as: Number of moles of hydrogen = 82 - 54 = 28 moles. Hence, 28 moles of hydrogen are required to crack one mole of the long saturated hydrocarbon chain (C40H82).

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The equilibrium constant Kp for the given reaction is approximately 7.8×10^59.

To calculate the equilibrium constant Kp from the equilibrium constants Kc, we need to consider the stoichiometry of the reaction and the relationship between Kp and Kc.

The  reactions are:

2NO(g) + Br2(g) ⇌ 2NOBr(g) (Kc = 1.9)

2NO(g) ⇌ N2(g) + O2(g) (Kc = 2.1×10^30)

We can obtain the desired reaction by multiplying the two given reactions:

(2NO(g) + Br2(g) ⇌ 2NOBr(g)) × (2NO(g) ⇌ N2(g) + O2(g))

This gives us:

4NO^2(g) + 2Br2(g) ⇌ 4NOBr(g) × N2(g) + O2(g)

The equilibrium constant Kp is related to Kc by the equation:

Kp = Kc^(Δn)

Where Δn is the change in the number of moles of gas between the products and reactants. In this case, Δn = (4 + 2) - (4) = 2.

Now we can calculate Kp using the  Kc values:

Kp = (Kc1)^(Δn1) × (Kc2)^(Δn2)

= (1.9)^2 × (2.1×10^30)^2

Calculating this expression gives us:

Kp ≈ 7.8×10^59

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Answer:

uhm

Explanation:

Answer:here:

Explanation:helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).

The ranking from the least to the most volume of base needed to neutralize the acids is as follows:

\(H_3AsO_4 < H_2SO_3 < H_2C_6H_6O_6 < HNO_2 < HC_2H_3O_2\).

To determine the order of acids requiring the least to the most volume of base for neutralization, we need to consider their molarities and the number of protons they can donate.

1. \(H_3AsO_4\) is a triprotic acid, meaning it can donate three protons (H+ ions) in sequential steps. It has a concentration of 0.060 M.

2. \(HC_2H_3O_2\) is a monoprotic acid, capable of donating a single proton. Its concentration is 0.15 M.

3. \(HNO_2\) is also a monoprotic acid with a concentration of 0.075 M.

4. \(H_2SO_3\) is a diprotic acid, having two protons to donate. It has a concentration of 0.060 M.

5. \(H_2C_6H_6O_6\) is another diprotic acid, with a concentration of 0.095 M.

To compare the acids, we need to consider their relative concentrations and the number of protons they can donate. Acids with higher concentrations or more protons will require more base for neutralization.

Based on the information provided, the ranking of acids in terms of the least to the most volume of base needed for complete neutralization is as follows:

1. \(H_3AsO_4\) (0.060 M) - It is the least concentrated acid on the list and a triprotic acid, meaning it can donate more protons in total. Therefore, it will require the least volume of base.

2. \(H_2SO_3\) (0.060 M) - Although it is a diprotic acid like \(H_2C_6H_6O_6\), its lower concentration suggests it will require a smaller volume of base for neutralization.

3. \(H_2C_6H_6O_6\) (0.095 M) - It is a diprotic acid but has a higher concentration compared to H2SO3, requiring a larger volume of base.

4. \(HNO_2\) (0.075 M) - It is a monoprotic acid with a higher concentration than \(H_2SO_3\), placing it in a higher position in the ranking.

5. \(HC_2H_3O_2\)(0.15 M) - It is a monoprotic acid and has the highest concentration among the acids listed, indicating that it will require the largest volume of base for complete neutralization.

Therefore, the ranking from the least to the most volume of base needed to neutralize the acids is as follows:

\(H_3AsO_4 < H_2SO_3 < H_2C_6H_6O_6 < HNO_2 < HC_2H_3O_2\).

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Answer:

Every species is made of different elements.

Explanation:

Living organisms are classified by their species. Species refer to a group of closely related individual organisms which are callable of interbreeding with each other and exchanging genetic material.

Member of a species have similar genetic make up and often look alike, it is the lowest taxonomic rank of closely related organisms.

Members of of different species are often composed of different elements. Since individual organisms are members of a given species, we can say that every species of organisms are made up of different elements.

Answer:

Stars which appear to revolve around the polar axis and do not set below the horizon can be viewed all year long.

The compound could have different molecular formula with different molar masses that still have the same empirical formula of C3H7O2

To determine the molecular formula of the compound with the given percentages of carbon (C), hydrogen (H), and oxygen (O), we can follow these steps:

Assume we have a 100 g sample of the compound. This means we have 49.30 g of C, 6.91 g of H, and 43.79 g of O.

Convert the masses of each element to moles using their respective molar masses (C: 12.01 g/mol, H: 1.008 g/mol, O: 16.00 g/mol).

Calculate the mole ratio of each element by dividing the moles of each element by the smallest number of moles obtained.

Round the resulting mole ratios to the nearest whole number to obtain the subscripts in the empirical formula.

Write the empirical formula using the subscripts obtained.

Based on the given percentages, the empirical formula of the compound is C3H7O2.

Without additional information about the molar mass of the compound, we cannot determine the molecular formula. The compound could have different molecular formulas with different molar masses that still have the same empirical formula of C3H7O2

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The hybridization of the carbon atom in carbon monoxide is sp, and the hybridization of the oxygen atom is sp.

To determine the hybridization of an atom, we need to consider the number of sigma bonds and lone pairs of electrons around that atom. In the Lewis structure of carbon monoxide (CO), we have a triple bond between carbon and oxygen, indicating the presence of one sigma bond and two pi bonds.

The carbon atom in carbon monoxide forms a triple bond with the oxygen atom, meaning it shares three electron pairs. In order to accommodate these three electron pairs, the carbon atom requires three atomic orbitals to hybridize.

One of these orbitals is an s orbital, and the other two are p orbitals. Therefore, the hybridization of the carbon atom is sp.

On the other hand, the oxygen atom in carbon monoxide forms a single bond with carbon, sharing one electron pair. It also has two lone pairs of electrons.

Considering these electron pairs, the oxygen atom requires three orbitals to hybridize. One of these orbitals is an s orbital, and the other two are p orbitals. Therefore, the hybridization of the oxygen atom is sp.

In conclusion, the carbon atom in carbon monoxide has sp hybridization, and the oxygen atom has sp hybridization. This hybridization allows both atoms to achieve the required geometry for their bonding and lone pairs of electrons.

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Answer:

that the polar bear will come out again in 2 years

One possible process to separate nickel tetracarbonyl and iron pentacarbonyl is fractional distillation. Since the boiling points of the two liquids are different, the process can take advantage of this difference to separate the components.

Fractional distillation works by heating the mixture in a distillation apparatus, which causes the liquids to vaporize. The vapor is then condensed back into a liquid and collected. However, the composition of the vapor is not uniform, with more volatile components having a higher concentration.

By using a fractionating column, which contains many plates or packing material, the vapor is forced to condense and evaporate multiple times.

As the vapor travels up the column, the components with lower boiling points will vaporize and travel up more easily, while the components with higher boiling points will condense and fall back down more frequently. This process effectively separates the components based on their boiling points.

In the case of nickel tetracarbonyl and iron pentacarbonyl, the fractional distillation apparatus would be set up, and the mixture would be heated. As the vapor rises up the column, the nickel tetracarbonyl, with its lower boiling point, would vaporize and travel up the column more easily, while the iron pentacarbonyl would condense and fall back down more frequently.

The components can then be collected separately at the end of the apparatus, resulting in the separation of the two liquids.

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The correct option is $26785.To calculate the total cost per equivalent unit using the weighted average method, we need to consider the costs incurred in both the beginning work in process and the units added during the period.

First, let's calculate the equivalent units of production for both conversion and materials:

Conversion costs:

Beginning work in process: 400 units × 20% complete = 80 equivalent units

Units added during the period: 2,000 units × 40% complete = 800 equivalent units

Total equivalent units for conversion = 80 + 800 = 880 equivalent units

Material costs:

Beginning work in process: 400 units × 30% complete = 120 equivalent units

Units added during the period: 2,000 units × 50% complete = 1,000 equivalent units

Total equivalent units for materials = 120 + 1,000 = 1,120 equivalent units

Next, let's calculate the total costs incurred:

Conversion costs:

Beginning work in process cost: $14,880

Costs added during the period: $409,200

Total conversion costs = $14,880 + $409,200 = $424,080

Material costs:

Beginning work in process cost: $9,900

Costs added during the period: $180,080

Total material costs = $9,900 + $180,080 = $189,980

Now, we can calculate the total cost per equivalent unit:

Total cost per equivalent unit = (Total conversion costs + Total material costs) / (Total equivalent units for conversion + Total equivalent units for materials)

Total cost per equivalent unit = ($424,080 + $189,980) / (880 + 1,120)

Total cost per equivalent unit ≈ $267.85

Therefore, the correct option is $26785.

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Answer:

ionically bonded compound transfer its electrons while covalently bonded compound share their electrons. ionically bonded compounds are charged while covalently bonded compound are neutral