Of the species, _____ is not an electrolyte
A. KBr
B. LiOH
C. RbNO3
D. He
E. HCl

The element first discovered in the Sun's spectrum and then found on Earth 30 years later is helium. In 1868, French astronomer Pierre Janssen and English astronomer Sir Norman Lockyer observed a yellow spectral line in the Sun's light during a solar eclipse.

This line did not correspond to any known element at that time. Lockyer and British chemist Edward Frankland suggested that the line was due to a new element, which they named "helium," after the Greek word for the Sun, "Helios." It was not until 1895, nearly 30 years after its initial discovery in the Sun's spectrum, that helium was found on Earth.

Scottish chemist Sir William Ramsay isolated helium by treating the mineral cleveite with acid. Ramsay's discovery confirmed the existence of helium as an element both in the Sun and on Earth. Helium is the second most abundant element in the universe and has various applications, including as a coolant in medical and scientific equipment, and in lighter-than-air balloons.

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According to OSHA (Occupational Safety and Health Administration), safety measures for using dental materials with potentially hazardous chemicals can be found in sources such as Material Safety Data Sheets (MSDS), OSHA's Hazard Communication Standard (HCS), and dental office safety manuals or protocols.

According to OSHA (Occupational Safety and Health Administration), safety measures that should be taken when using dental materials with potentially hazardous chemicals can be found in a few different sources:

Material Safety Data Sheets (MSDS): Manufacturers of dental materials are required to provide MSDSs for their products. These sheets contain detailed information about the potential hazards, safe handling procedures, storage recommendations, and emergency measures related to the chemicals present in the dental materials.

OSHA's Hazard Communication Standard (HCS): This standard requires employers to provide information and training to employees about the hazardous chemicals they may be exposed to in the workplace. The HCS ensures that employees have access to information on the hazards, proper handling, and use of hazardous chemicals, including dental materials.

Dental Office Safety Manuals or Protocols: Dental offices often develop their own safety manuals or protocols that outline specific safety measures for handling dental materials. These may include guidelines on proper storage, handling, personal protective equipment (PPE) requirements, spill cleanup procedures, and waste disposal methods.

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Answer:

56

Explanation:

Answer:

B!!! no because the shape will not be the same when the surface area is different

Explanation:

Tanya is not correct as per forces of attraction because the shape will not be the same when the surface area is different.

Forces of attraction  is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases  as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

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The freezing point of water will be lowered most by dissolving 1.0 mole of magnesium chloride (MgCl₂).

When a solute is dissolved in a solvent, such as water, it disrupts the orderly arrangement of water molecules, making it more difficult for them to form solid ice crystals. This disruption leads to a lowering of the freezing point of the solvent.

The extent to which the freezing point is lowered depends on the nature of the solute and its concentration. In this case, comparing the given options, dissolving 1.0 mole of magnesium chloride (MgCl2) will have the greatest effect on lowering the freezing point of water.

Magnesium chloride dissociates into three ions in water: one magnesium ion (Mg2+) and two chloride ions (Cl-). The presence of multiple ions increases the number of solute particles per mole, leading to a greater disruption of the water structure.

As a result, the freezing point depression caused by 1.0 mole of magnesium chloride is more significant compared to other solutes.

In contrast, naphthalene is a nonpolar solute and does not dissociate into ions in water. Sodium chloride (NaCl) dissociates into two ions, and ether is a nonpolar compound. Therefore, these substances would have a lesser effect on lowering the freezing point of water compared to magnesium chloride.

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A problem that can be tested using the scientific method is the association between greenhouse gases and global warming, in this case, the dependent variable is the temperature, the independent variable is the amount of gas and the controlled variables may be the presence of non-greenhouse gases.

A controlled variable in an experiment is any conditions manipulated by the researcher that allow us to make comparisons regarding the change in the dependent variable.

Therefore, with this data, we can see that controlled variables in an experiment are useful to determine the extension of the change in the dependent variable.

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Theoretically, 7.72 g containing ca(s) as well as 2.04 g of even more sulfur may be combined to produce 2.88 g of cas(s) (s).

Among the most rectifiers is sulfur (S), sometimes spelt as sulfur, a nonmetallic chemical element in the oxygenation member (Group 16 [VIa] of the atomic numbers). Natural sulfur is a pale yellow substance that is brittle, flavorless, and odorless.

Sulfur can be found naturally and now in metal bauxite ore. Natively, it can be found close to hot springs and volcanoes. The tenth most prevalent element, selenium is found in asteroids, the ocean, the crust of the earth, and the atmosphere.

balanced equation,

Ca + S ---> CaS

stoichiometry of Ca to S is 1:1

= Ca moles - 1.6 g/ 40 g/mol

= 0.04 mol

= S moles - 4.25 g / 32 g/mol

= 0.13 mol

stoichiometry of Ca to CaS is 1:1,

= CaS moles formed - 0.04 mol

= mass of CaS - 0.04 mol x 72 g/mol

theoretical yield = 2.88 g

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Answer:

The charge will tell you if the atom is neutral, positive, or negative. "The charge of an atom is the number of protons minus the number of electrons."

Gamma rays have the shortest wavelength

At body temperature, the average kinetic energy for the peptide is approximately 5.317 × 10⁻²¹ joules.

The peptide with 460 heavy atoms and 400 hydrogen atoms has:

Translational degrees of freedom: 3 (x, y, and z directions)

Rotational degrees of freedom: 2 (since it's a linear peptide, only two rotational axes are independent)

Vibrational degrees of freedom: 3(N - 1), where N is the total number of atoms

Total degrees of freedom = Translational + Rotational + Vibrational

= 3 + 2 + 3(460 + 400 - 1)

= 3 + 2 + 3(859)

= 3 + 2 + 2577

= 2582

Therefore, the peptide has 2582 degrees of freedom.

To calculate the average kinetic energy at body temperature (37 °C or 310.15 K), we can use the equipartition theorem, which states that each degree of freedom contributes (1/2)kT to the average energy, where k is the Boltzmann constant and T is the temperature.

Average kinetic energy = (1/2)(2582)(k)(310.15)

The numerical value of the average kinetic energy can be calculated using the known values for the Boltzmann constant and temperature.

Boltzmann constant (k) = 1.380649 × 10⁻²³ J/K

Temperature (T) = 310.15 K

Average kinetic energy = (1/2)(2582)(1.380649 × 10⁻²³ J/K)(310.15 K)

Calculating the average kinetic energy:

Average kinetic energy ≈ 5.317 × 10⁻²¹ J

Therefore, at body temperature, the average kinetic energy for the peptide is approximately 5.317 × 10⁻²¹ joules.

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Answer:

Molecular Mass

Explanation:

It's asking for the numerical quantity. That quantity would be the Molecular Mass. Take the sample mass and divide it by the molecular mass to get the number of moles.

(14g N * 2) + (1g H *4) = 32g / mol of N2H4

To get # of moles, divide the sample mass by the molecular mass

25g / 32g = 0.78125 moles

The alkali metals are six chemical elements in Group 1, the leftmost column in the periodic table. They are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr)

What qualities do alkali metals possess?

The alkali metals (lithium, sodium, potassium, rubidium, and cesium) are soft, glossy metals with low melting points when they are in their purest forms. Alkali metals easily react with moisture and the atmosphere. Special care must be used when using and storing these metals due to their reactivity.

The alkali metals in group 1 are so-called because, when treated with water, their oxides and hydroxides produce alkali solutions.

One of the most reactive metals is the alkali metal. They have greater atomic radii and low ionisation energies, which contribute to this. They have an oxidation state of 1, and they frequently give electrons during reactions. These metals stand out for their supple texture and silvery hue.

Alkalis can aid in the softening of drinkable water and the eradication of contaminants including manganese, fluorides, and organic tannins. The National Lime Association claims that in order to absorb and neutralise sulphur oxides and help prevent acid rain, heavy enterprises use alkali in the form of lime.

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Elements that belong to alkali metal family  are Lithium(Li), Sodium(Na), Potassium (K), Rubidium (Ru), Cesium (Cs) and Francium (Fr) .

An element is a substance that can not be damaged down into a simpler layout. They may be distinguished by means of a completely unique atomic range. The elements are organized via their atomic variety in the periodic table, which highlights elements with similar residences.

Carbon is the most important detail to existence. With out this detail, existence as we are aware of it might not exist. As yo u will see , carbon is the vital element in compounds essential for lifestyles.

Kinds of elements :

1.) The elements are categorized as metallic, non-metal, and metalloid.

2.) The intense left aspect factors inside the periodic desk are metals, as an example, sodium, calcium, cesium, and many others.

3)  Elements on the right side are usually known as non-metals, carbon, chlorine, oxygen, and many others.

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Answer:Solve for X+ 2x=

Explanation:

Answer:

C

Explanation:

Answer:

C - 3

Explanation:

This can be actually tested

There are several steps to draw lewis dot structure of any chemical compound. Here, we taking RbF.  Structure is given below with the image.

1. Start by writing the chemical symbol for the element at the center of the structure. In this case, it is Rb for Rubidium.

2. Draw dots around the symbol to represent the valence electrons. Rb has one valence electron, so you would put one dot around the Rb.

3. Next, write the chemical symbol for the other element in the compound, in this case F for Fluorine.

4. Draw dots around the symbol to represent the valence electrons. Fluorine has 7 valence electrons, so you would put 7 dots around the F.

5. To create the bond between the two elements, use a pair of dots to connect the Rb and F. This represents the sharing of electrons between the two elements.

So the Lewis dot structure for RbF would be represented as:

        . .

Rb+ [:F:]

        . .

This representation shows that Rb and F share one pair of electrons, forming a bond between them, and the dots around Rb and F represent the remaining number of valence electrons that are not involved in the bond.

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False. A mixture of gaseous hydrogen and nitrogen cannot be considered a pure substance because it contains two or more different types of particles (hydrogen and nitrogen) which cannot be broken down by physical means into simpler substances of different components.

In chemistry, a pure substance is a type of matter consisting of a single type of particle or matter. It can be broken down into simpler substances, either chemically or physically, but it always contains the same number of atoms or molecules and therefore retains its chemical properties.

Pure substances include elements (such as oxygen, iron, and gold) and compounds (such as water, carbon dioxide, and sodium chloride). Mixtures, on the other hand, are composed of two or more pure substances and can be separated into their components by physical means, such as filtration or distillation.

Therefore, a mixture of gaseous hydrogen and nitrogen is not a pure substance.

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Answer:

Chemical Change

Explanation:

The explosion of fireworks is an example of chemical change. During a chemical change, substances are changed into different substances. In another words, the composition of the substance changes.

Hydrogen changes from a gas to a liquid at a temperature of -252.77°C (-422.99°F) and from a liquid to a solid at a temperature of -259.2°C (-434.6°F). It is slightly soluble in water, alcohol, and a few other common liquids.

Subscript D indicates that the measurement was made using light with a wavelength of 589.3 nm

A more detailed explanation of the answer.

The subscript D in the relative refractive index for decane as n'26 D = 1.4110 refers to the wavelength of the light being used in the measurement. In this case, the subscript D indicates that the measurement was made using light with a wavelength of 589.3 nm (the D-line of the sodium spectrum).

Which is a specific wavelength of light (approximately 589.3 nm) emitted by a sodium lamp. The refractive index is measured using this light source to ensure consistency in the measurements.

This means that the value of the refractive index obtained using light of a different wavelength would be different. Therefore, it is important to specify the wavelength used when reporting the refractive index.

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The purpose of HCl in the first step is to make aniline more nucleophilic. Option E is correct.

The purpose of HCl in the first step is to protonate the amino group of aniline, which makes it more reactive and therefore more nucleophilic. This protonation reaction also helps to activate aniline towards electrophilic substitution reactions, such as the nitration or acylation of aniline.

Nucleophilic refers to a species or atom that has a tendency to donate an electron pair to form a new covalent bond with an electron-deficient species, known as an electrophile. In other words, a nucleophile is an electron-rich species that is attracted to regions of positive charge or electron deficiency.

This type of reaction is known as nucleophilic substitution or addition reactions, and is an important class of chemical reactions in organic chemistry.

Hence, E. to make aniline more nucleophilic is the correct option.

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--The given question is incomplete, the complete question is

"What is the purpose of HCl in the first step? group of answer choices A) to activate aniliine B) to deactivate aniline C) to disrupt the aromaticity of aniline D) to remove hydrogen from aniline E) to make aniline more nucleophilic."--

A student synthesizes tin oxide to create a compound with generic formula SnxOy. She does this by combining 30.80 g of tin and when the tin oxide product is produced, the total mass of the product is 39.10 g.  the correct answer is B) 0.25946.

To determine the number of moles of tin in the product, we first need to calculate the number of moles of tin and the number of moles of oxygen in the product.

Given:

Mass of tin (Sn) = 30.80 g

Total mass of product (SnxOy) = 39.10 g

Molar mass of tin (Sn) = 118.71 g·mol⁻¹

To find the number of moles of tin (Sn) in the product, we can use the following formula:

Number of moles = Mass / Molar mass

Number of moles of tin (Sn) = 30.80 g /  the correct answer is B) 0.25946.118.71 g·mol⁻¹

Now let's calculate the value:

Number of moles of tin (Sn) = 0.25946 (rounded to five decimal places)

Therefore, the number of moles of tin in the product is 0.25946 (approximately 0.25946 moles).

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Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits belonging to the same class of chemicals.  The following is an exception to this statement is:

c) Steroids

Large organic molecules, such as proteins, nucleic acids, and carbohydrates, are typically formed through the process of polymerization. Polymerization involves the repetitive bonding of smaller subunits, known as monomers, to form a long chain or polymer. These monomers usually belong to the same class of chemicals, meaning they have similar structures and functional groups.

In the case of DNA, the monomers are nucleotides, which consist of a sugar molecule, a phosphate group, and a nitrogenous base. The repetitive bonding of nucleotides creates a long chain of DNA.

Similarly, cellulose, a major component of plant cell walls, is composed of repeating units of glucose monomers. The polymerization of glucose molecules forms long cellulose chains.

Contractile proteins, such as actin and myosin found in muscle fibers, are also assembled through the polymerization of monomers. These monomers, called amino acids, are linked together by peptide bonds to form polypeptide chains, which then fold into the functional protein structure.

However, steroids, including molecules like cholesterol, estrogen, and testosterone, are an exception to this general pattern of polymerization. Steroids have a distinct structure consisting of four fused carbon rings. They are not formed through repetitive bonding of identical subunits like proteins or nucleic acids. Instead, steroids are synthesized through specific biosynthetic pathways in living organisms.

While steroids play crucial roles in various physiological processes, they do not follow the typical pattern of polymerization seen in other organic polymers.

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The complete question is:

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits belonging to the same class of chemicals. which of the following is an exception to this statement?

a) DNA

b) cellulose

c) steroids

d) a contractile protein

Viscosity of polystyrene is determined to know the size of polystyrene its compression, and molding capacity.

To obtain the perfect shape and size the configuration of polystyrene should be maintained under different conditions.

So, to deduce the confirmation of the polystyrene under viscosity determination  we can apply 2 methods;

1. By adding excess diluents to the polystyrene which reduces its viscosity.

2. By introducing or adding small linear chains by addition method to the molecular chains of polystyrene molecular structure to reduce chain entanglement.

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Answer:

Explanation:

A

Answer:

A

The nuber of each one should be same

Answer:False

Explanation:Atoms can only have up to 8 valence electrons

We can say that is receding away from us about a cloud of hydrogen gas with this same emission line at 680.2 nm.

The element hydrogen is represented by the symbol 'H' and atomic number 1. Hydrogen is the lightest element. Hydrogen is typically a gas with the formula H 2 composed of diatomic molecules. It is exceedingly combustible, colorless, tasteless, odorless, and non-toxic.

Additionally, hydrogen is a fuel source of internal combustion engines. However, they produce exhaust emissions and are less efficient than FCEVs. Learn more about fuel cells. The energy content of a gallon of fuel (6.2 pounds, 2.8 kg) is comparable to that of 2.2 lbs, or 1 kilogram, of hydrogen gas.

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Answer:

Independent variable

Explanation: