Two methods that can analyze fibers are

a
Polarizing light spectroscopy and infrared microscopy
b
Polarizing light microscopy and infrared spectroscopy
c
None of the above

2.50 g of helium gas at STP would occupy a volume of 14.0 liters.

Standard temperature and pressure (STP) conditions of 0°C and 1 atm, we can use the molar volume of a gas at STP, which is 22.4 L/mol.

1. Helium seems to have a molar mass of 4.00 g/mol.

Therefore, we can calculate the number of moles of helium as:

moles of He = mass of He divided by molar mass of He

= 2.50 g / 4.00 g/mol

= 0.625 mol

Then, we can use the molar volume of a gas at STP to calculate the volume of helium gas:

volume of He = moles of He x molar volume of gas at STP

= 0.625 mol x 22.4 L/mol

= 14.0 L

2.50 g of helium gas at STP would occupy a volume of 14.0 liters.

2. The molar mass of sodium is 22.99 g/mol. Therefore, we can calculate the number of moles of sodium as:

moles of Na = number of atoms of Na divided by Avogadro's number

= 5.0 x 10²⁵ atoms / 6.022 x 10²³ atoms/mol

= 83.0 mol

Then, we can use the molar mass of sodium to calculate the mass of sodium:

mass of Na = moles of Na x molar mass of Na

= 83.0 mol x 22.99 g/mol

= 1900 g

Therefore, 5.0 x 10²⁵ atoms of sodium have a mass of 1900 g.

3. The molar mass of Ni is 58.69 g/mol. Therefore, we can calculate the number of moles of Ni as:

moles of Ni = mass of Ni divided by molar mass of Ni

= 3.95 g / 58.69 g/mol

= 0.0673 mol

Then, we can use Avogadro's number to calculate the number of atoms of Ni:

number of atoms of Ni = moles of Ni x Avogadro's number

= 0.0673 mol x 6.022 x 10²³ atoms/mol

= 4.05 x 10²² atoms

Therefore, 3.95 g of Ni contain 4.05 x 10²² atoms.

4. The molar mass of Xe is 131.29 g/mol. Therefore, we can calculate the number of moles of Xe as:

moles of Xe = mass of Xe divided by molar mass of Xe

= 15 kg / 131.29 g/mol

= 114 mol

Then, we can use Avogadro's number to calculate the number of atoms of Xe:

number of atoms of Xe = moles of Xe x Avogadro's number

= 114 mol x 6.022 x 10^23 atoms/mol

= 6.87 x10²⁵ atoms

Therefore, a 15 kg sample of Xe gas contains 6.87 x 10²⁵ atoms.

5. A gas's molar volume at STP is 22.4 L/mol. Therefore, we can calculate the number of moles of Ar as:

moles of Ar = number of atoms of Ar divided by Avogadro's number

= 45,000,000 atoms / 6.022 x 10²³ atoms/mol

= 7.47 x 10⁻¹⁷ mol

Then, we can use the molar volume of a gas at STP to calculate the volume of Ar gas:

volume of Ar = moles of Ar x molar volume of gas at STP

= 7.47 x 10⁻¹⁷ mol x 22.4 L/mol

= 1.67 x  10⁻¹⁵ L

Therefore, 45,000,000 atoms of Ar would occupy a volume of 1.67 x 10⁻¹⁵ liters at STP.

6. The molar mass of CO₂ is 44.01 g/mol. Therefore, we can calculate the number of moles of CO₂ as:

moles of CO₂ = mass of CO₂ divided by molar mass of CO₂

= 75 g / 44.01 g/mol

= 1.70 mol

Then, we can use Avogadro's number to calculate the number of atoms of CO₂:

number of atoms of CO₂ = moles of CO₂ x Avogadro's number

= 1.70 mol x 6.022 x 10²³ atoms/mol

= 1.02 x 10²⁴ atoms

Therefore, a 75 g sample of CO₂ contains 1.02 x 10²⁴ atoms.

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The mass of hydrogen gas produced when 12 grams of zinc reacts with excess sulfuric acid is 0.370 g.

Ratio between the mass and amount of substance (measured in moles) of any sample is called molar mass.

Zn + H2SO4 -> ZnSO4 + H2

Molar mass of zinc is 65.38 g/mol.

moles of zinc is mass of zinc / molar mass of zinc

moles of zinc = 12 g / 65.38 g/mol

moles of zinc = 0.1838 mol

Moles of hydrogen gas is equal to moles of zinc

moles of hydrogen gas = 0.1838 mol

So, mass of hydrogen gas = moles of hydrogen gas x molar mass of hydrogen gas

mass of hydrogen gas = 0.1838 mol x 2.016 g/mol (molar mass of H2)

mass of hydrogen gas = 0.370 g

Therefore, the mass of hydrogen gas produced when 12 grams of zinc reacts with excess sulfuric acid is 0.370 g.

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Answer:

Explanation:

To calculate the percent yield of a reaction, we need to compare the actual yield (the amount of product obtained in the experiment) with the theoretical yield (the amount of product that should have been obtained based on stoichiometric calculations).

The balanced chemical equation for the reaction between magnesium bromide (MgBr2) and hydroiodic acid (HI) is:

MgBr2 + 2HI → MgI2 + 2HBr

From this equation, we can see that 1 mole of MgBr2 reacts with 2 moles of HI to produce 1 mole of MgI2 and 2 moles of HBr. We can use this information to calculate the theoretical yield of HBr that should have been obtained based on the amount of MgBr2 used:

Calculate the moles of MgBr2 used:

moles of MgBr2 = mass / molar mass = 24.5 g / 184.11 g/mol = 0.133 moles

Use the mole ratio from the balanced equation to calculate the moles of HBr that should have been produced:

moles of HBr = 2 x moles of MgBr2 = 2 x 0.133 moles = 0.266 moles

Calculate the mass of HBr that should have been produced:

mass of HBr = moles of HBr x molar mass = 0.266 moles x 80.91 g/mol = 21.47 g

So the theoretical yield of HBr is 21.47 g.

The actual yield of HBr obtained in the experiment is 8.23 g.

We can now calculate the percent yield as:

percent yield = (actual yield / theoretical yield) x 100%

percent yield = (8.23 g / 21.47 g) x 100%

percent yield = 38.4%

Therefore, the percent yield of the reaction is approximately 38.4%.

Answer:

controls involuntary movements of other organ systems

Explanation:

Answer: As an example, we can decompose copper carbonate into its constituent elements, copper, oxygen, and carbon, weighing each and taking the ratios of these masses. The result is that every sample of copper carbonate is 51.5% copper, 38.8% oxygen, and 9.7% carbon.

Explanation:

Chemical bonds involve the interaction between nuclei and electrons. Option D.

Chemical bonds are formed through the interaction between atoms, where electrons in the outermost energy level (valence electrons) are shared, gained or lost between atoms.

This results in the formation of a more stable compound. In these interactions, the positively charged nucleus of each atom attracts the negatively charged electrons of the other atom, creating a bond.

The strength of the bond is determined by the distance between the nuclei and the number of electrons shared between them.

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The pH of pure water at 60°C is approximately 7.02, which indicates a neutral solution.

At 60°C, the ion product constant of water,[tex]Kw, is 9.25 × 10^–14.[/tex]

For pure water at this temperature, the concentration of H+ ions is equal to the concentration of OH- ions, so we can write:

[tex]Kw = [H+][OH-] = (x)(x) = x^2[/tex]

where x is the concentration of H+ ions (and also OH- ions) in mol/L.

Taking the square root of both sides, we get:

[tex]x = sqrt(Kw) = sqrt(9.25 × 10^–14) = 9.62 × 10^–8 mol/L[/tex]

Therefore, the pH of pure water at 60°C is:

[tex]pH = -log[H+] = -log(9.62 × 10^–8) = 7.02[/tex]

So the pH of pure water at 60°C is approximately 7.02, which indicates a neutral solution.

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a. The measurements on the target do not represent accuracy well.

b. The measurements on the target represent precision fairly well.

Accuracy refers to the closeness of a measurement to the true or accepted value. Since they are off target, the measurements are not accurate.

Precision refers to the consistency and reproducibility of measurements, and in this case, the shots are clustered around certain areas, with two points in the second circle and two points in the third circle. This indicates that the person taking the shots was able to consistently hit a certain area.

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The fact that the earth is too dry is what most likely prevents mangrove trees from growing in deserts.

All of these trees flourish in low-oxygen soil regions with slowly flowing rivers that permit the accumulation of fine sediments. Because mangrove trees cannot withstand subfreezing conditions, they can only be found close to the equator in tropical and subtropical latitudes.

Mangroves are only found close to protected beaches in tropical or subtropical ltiatudes since they are unable to withstand subfreezing temperatures. They all possess the unique capacity to thrive in salted soil that is within the range of the tides.

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Answer: 6.04 atm

Explanation:

PV = nRT

plug in the given values and solve for P:

n = 1.5 moles

V = 5.8 L

R = 0.08206 L·atm/(mol·K) (gas constant)

T = 294 K

P = nRT/V

P = (1.5 mol) x (0.08206 L·atm/(mol·K)) x (294 K) / (5.8 L)

P = 6.04 atm

Therefore, the pressure inside the chamber is 6.04 atm

The balanced equation is;

Ba(OH)2 + CO2 → BaCO3 + H2O

Here are the general steps to balance a chemical equation by atom count:

Write the unbalanced equation for the reaction, showing the formulas of the reactants and products.

Count the number of atoms of each element present on the reactant side and the product side of the equation.

Identify the element with the largest atom count that is unbalanced.

Balance this element by adjusting the coefficient of one of the reactants or products.

Recount the atoms of this element on both sides of the equation and adjust the coefficient of another reactant or product as necessary.

Repeat steps 4 and 5 for each element that is unbalanced until the equation is balanced.

Check your balanced equation to make sure that the same number of atoms of each element is present on both the reactant and product sides of the equation.

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The mole fraction of NaCI in the solution is 0.079 when  7.7 g of NaCl is dissolved in 40 g of water.

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

Number of moles of NaCl =7.7/40=0.1925 and number of moles of water =40/18=2.22 thus mole fraction= 0.1925/2.414=0.079.

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The N - H and the C- O  and the C- N bonds in indigo dye are polar on nature.

Indigo is a blue dye that is derived from the leaves of certain plants. The chemical structure of indigo consists of two benzene rings connected by a nitrogen atom. The molecule has several polar bonds due to the electronegativity differences between the atoms.

The polar bonds in indigo include:

The nitrogen-carbon bonds: The nitrogen atom in the middle of the molecule is connected to two carbon atoms, one in each benzene ring. Nitrogen is more electronegative than carbon, so the nitrogen-carbon bonds are polar.

The carbon-oxygen bonds: Indigo has two oxygen atoms that are double bonded to carbon atoms in the benzene rings. Oxygen is more electronegative than carbon, so the carbon-oxygen bonds are also polar.

The carbon-nitrogen bond: The nitrogen atom in the middle of the molecule is also connected to a carbon atom in one of the benzene rings. This bond is polar due to the electronegativity difference between carbon and nitrogen.

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The given statement is true. In order for an electron to go back to the ground state, the atom emits the excess energy in the form of a photon.

After absorbing the energy, the electron advances to a higher energy state. In the opposite process, called emission, the electron releases the excess energy it had taken up and goes back to its ground state.

The energy of the electron drops when it changes levels, and the atom releases photons. The emission of the photon occurs as the electron transitions from a higher to a lower energy state. The energy of the photon is precisely the energy that is lost when an electron moves to a level with less energy.

Because each element has a different amount of electrons and hence a diverse range of energy levels, each element's spectra are distinct.

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The mass of 6.45 x 10^25 atoms of Cu is 682.3 grams. For example, the atomic weight of carbon is 12.011, so the molar mass of carbon is 12.011 g/mol.

What is Molar Mass?

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mole). It is a fundamental concept in chemistry and is used in various calculations, such as determining the mass of a sample of a substance, the number of moles in a sample, or the number of atoms or molecules in a sample.

The molar mass of an element is equal to its atomic weight, which is the weighted average of the masses of all the isotopes of that element, taking into account their relative abundance.

Determine the number of moles of Cu atoms:

6.45 x 10^25 atoms Cu x (1 mole Cu / 6.022 x 10^23 atoms Cu) = 10.73 mol Cu

Use the molar mass of Cu to convert from moles to grams:

10.73 mole Cu x (63.55 g Cu / 1 mole Cu) = 682.3 g Cu

Therefore, the mass of 6.45 x 10^25 atoms of Cu is 682.3 grams.

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Answer:

T

=

447

K

≈

174

∘

C

.

Explanation:

This is what we're given:

P

(pressure), which is

1.95 atm

.

V

(volume), which is

12.30 L

.

n

(number of moles), which is

0.654

moles of neon gas.

We have to find

T

, or temperature. To do this, we'll need to use the Ideal Gas Law, which is:

P

V

=

n

R

T

Rearranging this equation to get temperature on one side, we get:

T

=

P

V

n

R

Pressure is in

a

t

m

and volume is in

L

. This tells us that we'll need to use the value of

0.08206 L atm/K mol

for

R

, the ideal gas constant.

Plugging in all of the values, we can solve for temperature:

T

=

p

V

n

R

T

=

1.95

atm

×

12.30

L

0.654

mol

×

0.08206

L

atm

K

−

1

mol

T

=

447

K

We can then convert to celsius, which equals to around

174

∘

C

.

Answer link

Explanation:

A change in water temperature is likely to have a negative effect on reproduction in both organisms that live near a freshwater ecosystem.

Since both organisms are adapted to the water temperature of their environment, and any increase or decrease in temperature can cause their reproductive processes to be disrupted. For example, an increase in water temperature can cause an increase in the metabolic rate of the organisms, leading to a decrease in the amount of energy available for reproduction.

Also, an increase in water temperature can cause an increase in water evaporation, leading to a decrease in the amount of water available for the organisms, which can also negatively affect their reproductive processes.

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The term chemical formula is also called the molecular formula of a compound which represents the total number of atoms of each constituent elements present in one molecule of the compound.

The chemical formula is defined as the symbolic representation which gives the chemical composition of a compound. They also denotes the ratios in which the constituent elements combine to form the compound.

The chemical formula of a compounds with an element hydrogen are HCl, NH₃, HNO₃, etc. whereas the chemical formula of the compounds with an element 'O' are H₂O, H₂O₂, OH⁻, etc.

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The effect of change of pressure, concentration and temperature on the state of equilibrium can be predicted with the help of Le Chatelier's principle.

If a system in equilibrium is subjected to a change in concentration, pressure or temperature, the equilibrium shifts in the direction that tends to reduce the effect of the change.

According to Le Chatelier's principle, the increase of temperature will shift the equilibrium in the direction of endothermic reaction. Here the forward reaction is exothermic, so more amount of CH₃OH will be produced.

If H₂ is added, more amount of CH₃OH will be produced and less amount of CO will be present.

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Answer:

it is 6E23 moles

Explanation:

At 824.1 torr + 55.9°C, dry butane has a of 0.937 L. The basic formula for size is length, breadth, and height, as volume opposed to length, width, and height for the surface of a rectangular shape.

Any three-dimensional solid's volume is the area it takes up. The shapes of these solids include cubes, cuboids, cones, cylinders, and spheres. Forms come in a wide range of volumes.

Volumes will be calculated using three different techniques: geometrically (measured lengths); water displace; and pycnometry, to demonstrate the effects of precision on data.

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Answer:

B) increases

Explanation:

The order of the scientists in terms of when they lived and were prominent is :

Robert Boyle was an Irish natural philosopher and chemist who is best known for his contributions to the field of modern chemistry. Hennig Brand was a German alchemist who is credited with discovering the element phosphorus in 1669.

J.J. Thomson was British physicist who is best known for his discovery of the electron in 1897.  Marie Curie was a Polish-born French physicist and chemist who is best known for her pioneering work on radioactivity.

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80.0 liters of hydrogen gas at STP can produce 37.1 grams of ammonia.

To answer this question, we need to know the balanced chemical equation for the reaction between hydrogen and ammonia:

N2 + 3H2 → 2NH3

From this equation, we can see that 3 moles of hydrogen are required to produce 2 moles of ammonia.

Now, we need to convert 80.0 liters of hydrogen to moles. We can use the ideal gas law to do this:

PV = nRT

where;

Assuming standard temperature and pressure (STP), which is 0°C (273 K) and 1 atm, respectively, we can use the following values:

Plugging these values into the ideal gas law, we get:

n = PV/RT = (1 atm)(80.0 L)/(0.08206 L·atm/mol·K)(273 K)

n = 3.27 moles of H2

Now, we can use the stoichiometry of the balanced equation to determine the number of moles of NH3 produced:

3 moles of H2 produces 2 moles of NH3

Therefore, 3.27 moles of H2 produces:

(2 moles of NH3 / 3 moles of H2) x 3.27 moles of H2 = 2.18 moles of NH3

Finally, we can use the molar mass of NH3 to convert moles to grams:

2.18 moles of NH3 x 17.03 g/mol = 37.1 g of NH3

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Chalcopyrite's sole significant application is as a copper ore, yet the significance of this one use cannot be overstated. as a minor copper resource and as examples of minerals.

It is brassy to golden yellow in color and rates 3.5 to 4 on the Mohs scale for hardness. The streak clearly shows a greenish hue to it. Brass yellow with a potential for iridescent purplish tarnish. mainly the disphenoid, resembles a tetrahedron, is frequently large, and occasionally has a botryoidal shape.

Chalcopyrite is a copper and iron sulfide mineral that is the most prevalent copper mineral and a significant copper resource. In ore veins deposited at medium to high temperatures, such as those in Rio Tinto, it often occurs.

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Answer:

49.05

Explanation:

weight = mass × gravity

49.05 = 5 × 9.81

Answer:

5kg is still 5kg on Earth

In pounds it would be 11.02lbs

The answer to the question indicates that C2H4 belongs to the identical homologous series as C3H6. The correct option is A) .

A mixture is a material that is created chemically when two or more components are mixed in a certain weight ratio. They have distinct physical and chemical features and are homogenous. The compound water is an example. It is composed of the two chemicals hydrogen as well as oxygen, which chemically combine in a predetermined weight-to-ratio of 1:8.

A compound is made up of atoms from several elements that have been chemically mixed in a certain ratio. A pure chemical compound comprised of the same atom is called an element. Composition.

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