The density of helium in a balloon is 1.18 g/L. If a balloon holds 2.93 L of He, how many atoms of He are in
the balloon?

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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The mass of chlorine in 4.75 mg of Freon-12 is approximately 1.39 x [tex]10^{-3}[/tex]g.

What is Mass?

Mass is a fundamental property of matter that measures the amount of substance or material present in an object. It is a scalar quantity and is typically measured in units such as grams (g) or kilograms (kg) in the metric system, or pounds (lb) or ounces (oz) in the imperial system.

Freon-12, also known as dichlorodifluoromethane, is a chlorofluorocarbon (CFC) compound that was used as a refrigerant and propellant in aerosol products. Its chemical formula is CCl2F2.

The atomic masses of carbon (C), chlorine (Cl), and fluorine (F) are approximately 12.01 g/mol, 35.45 g/mol, and 18.998 g/mol, respectively.

The molar mass of Freon-12 (CCl2F2) is:

Molar mass of Freon-12 = 12.01 g/mol (C) + 2 x 35.45 g/mol (Cl) + 2 x 18.998 g/mol (F)

= 120.91 g/mol

Next, we use the formula:

moles = mass / molar mass

to calculate the number of moles of Freon-12 in 4.75 mg:

moles of Freon-12 = 4.75 mg / 120.91 g/mol

= 3.92 x 10^-5 mol

Finally, we use Avogadro's number to calculate the number of molecules of Freon-12:

Number of molecules = moles of Freon-12 x Avogadro's number

= 3.92 x[tex]10^{-5}[/tex] mol x 6.022 x[tex]10^{23[/tex] molecules/mol

= 2.35 x [tex]10^{19}[/tex] molecules

To calculate the mass of chlorine in 4.75 mg of Freon-12, we can use the molar mass of chlorine (Cl) and the moles of Freon-12 calculated above.

The molar mass of chlorine (Cl) is 35.45 g/mol.

Mass of chlorine in Freon-12 = moles of Freon-12 x molar mass of chlorine

= 3.92 x [tex]10^{-5}[/tex] mol x 35.45 g/mol

= 1.39 x [tex]10^{-3}[/tex] g

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It took Approximately 52 minutes and 40 seconds for an electromagnetic signal to travel to Earth from Pioneer 11 when it was near Jupiter.

The speed of light, which is the speed at which an electromagnetic signal travels in a vacuum, is approximately 299,792,458 meters per second.

To find out how long it takes for an electromagnetic signal to travel from Pioneer 11 to Earth when it was near Jupiter, we can use the formula:

The distance between Pioneer 11 and Earth when it was near Jupiter is approximately 998 million km, or 998,000,000 km.

Converting this distance to meters, we get:

Dividing the distance by the speed of light, we get:

Converting this time to minutes and seconds, we get:

Rounding to the nearest minute and second, we get:

Therefore, it took approximately 52 minutes and 40 seconds for an electromagnetic signal to travel from Pioneer 11 to Earth when it was near Jupiter.

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Food, clothing, shelter, health, energy, and clean air, water, and soil are all dependent on chemistry. Chemical technologies improve our quality of life in a variety of ways by solving problems in health, materials, and energy utilization.

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The mass (in grams) of the sample that will decay in 800 years, given that the half-life is 1600-years is 0.78 g

We shall begin our calculation by obtaining the number of half lives that has elapsed after 800 years. Details below:

n = t / t½

n = 800 / 1600

n = 0.5

Next, we shall determine the amount remaining after 800 years. Details below:

N = N₀ / 2ⁿ

N = 2.5 / 2^0.5

N = 1.77 g

Finally, we shall obtain the mass of the sample that has decayed in 800 years. Details below:

Mass that decay = N₀ - N

Mass that decay = 2.5 - 1.77

Mass that decay = 0.78 g

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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 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.

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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0.0882 moles of silver bromide (AgBr) will form.

calculating the number of moles of silver nitrate (AgNO₃) used in the reaction:

moles of AgNO₃ = mass / molar mass

The molar mass of AgNO₃ is:

AgNO₃: 107.87 + 14.01 + 3(16.00) = 169.87 g/mol

So, the number of moles of AgNO₃ used is:

moles of AgNO₃ = 15.0 g / 169.87 g/mol = 0.0882 mol

Since the reaction occurs in a 1:1 ratio of AgNO₃ to AgBr, the number of moles of AgBr produced will also be 0.0882 mol.

Therefore, 0.0882 moles of silver bromide (AgBr) will form.

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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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Elements on the transition metal has the highest tendency to gain are chromium and manganese.

Transition metals typically have the ability to lose electrons to form positive ions, rather than to gain electrons to form negative ions. However, some transition metals can gain electrons under certain conditions.

The tendency to gain electrons (electron affinity) generally increases across a period from left to right on the periodic table, and decreases down a group from top to bottom.

Among the transition metals, the element with the highest electron affinity is usually considered to be either chromium [Cr] or manganese [Mn]. Both of these elements have a relatively high electron affinity due to their electronic configurations and the proximity of their valence electrons to the nucleus.

However, it is important to note that electron affinity values can vary depending on the specific experimental conditions used to measure them.

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The elements on the transition metal that have the highest tendency to gain are chromium and manganese.

Usually, transition metals form positive ions by losing electrons rather than gaining electrons to form negative ions. However, under certain conditions, some transition metals can gain electrons. The tendency to gain electrons is known as electron affinity.

This tendency generally increases as we go across a period from left to right in our periodic table and decreases while going down the group from top to bottom.

The element with the highest electron affinity, among the transition metals, is usually considered to be either manganese [Mn] or chromium [Cr]. Both of them have a relatively high electron affinity because of their electronic configurations and the proximity of their valence electrons to the nucleus.

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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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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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Answer: the mass of 7.55 x 10^21 molecules of water is 0.226 g, which corresponds to option (c).

Explanation: The atomic weight of water (H2O) is:

2(1.008 g/mol) + 15.999 g/mol = 18.015 g/mol

Avogadro's number (NA) is:

6.022 x 10^23 molecules/mol

To calculate the mass of 7.55 x 10^21 particles of water, able to utilize the taking after equation:

mass = (number of atoms / Avogadro's number) x atomic weight

mass = (7.55 x 10^21 / 6.022 x 10^23) x 18.015 g/mol

mass = 0.226 g

Several factors can dictate entropy in an equation.

These include:

1. Phase changes

⇒ When a solid turns to a liquid, the entropy increases as the particles have more freedom to move around and thus have a greater ability for 'disorder'. Same goes for a liquid turning to a gas. In a gas, the intermolecular forces are much weaker than that of a solid or liquid, allowing the particles more freedom.

So, going from a solid to liquid to gas increases entropy, and going the other way, from gas to liquid to solid, decreases entropy.

Example:

H₂O(l) -> H₂O(g)

This will have a positive entropy change, as the water molecules are becoming gaseous and thus have more freedom.

2. Dissolution

⇒ Similarly, breaking up particles of a solute when dissolving in a solvent will increase entropy as the particles are no longer bound together.

So, dissolving a solute will increase entropy.

Example:

NaCl(s) -> NaCl(aq)

This will have a positive entropy change, as the NaCl particles are more free after being separated.

3. Number of products and reactants

⇒ Generally, if you have more moles of products than reactants, if they are the same phase then entropy will increase. Note this is not necessarily true if you form a gas from two non-gas reactants, as the gas will still have more entropy.

4. Temperature

⇒ Increasing temperature will increase entropy as the particles have more kinetic energy and are then moving faster.

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l. 2N2(g) + O2(g) → 2N2O(g)

3 moles of gas are forming 2 moles of gas. The phase of products and reactants are the same, so since we have less moles of product than reactant, entropy will be negative.

II. CaCO3(s) → CaO(s) + CO2(g)

1 mole of solid is forming 1 mole of solid and 1 mole of gas. There is a phase change from solid to gas, and there are more moles of product than reactant, entropy will be positive.

III. Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)​

While 3 moles of reactant are forming only 2 moles product, we are forming a gas from non-gaseous reactants, so entropy will be positive regardless.

The number of atoms of each element is now the same on both sides, so the equation is balanced.

Nothing can be created or destroyed, according to the conservation of matter principle. The quantity of each element's atom in the reactants and the quantity of that same element in the products must match in chemical equations.

As soon as atoms distribute their electrons uniformly, a nonpolar covalent bond is formed. Normally, this happens when two atoms have comparable or identical electron affinities. The greater the attraction, the closer the values of their electron affinities are. This happens in gas molecules, also referred to as diatomic substances.

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The balanced equation for the given redox reaction in basic solution is:

NO2^- + Fe3+ + H2O → NO3^- + Fe2+ + OH^-

Here, NO2^- is oxidized to NO3^-, which means it loses electrons and undergoes an oxidation reaction. Fe3+ is reduced to Fe2+, which means it gains electrons and undergoes a reduction reaction.

To balance the equation in basic solution, we first balance the atoms that are not hydrogen or oxygen. We start with the Fe3+ ion, which is reduced to Fe2+. To balance the iron atoms, we add one electron to the left side of the equation:

Fe3+ + e^- → Fe2+

Next, we balance the nitrogen and oxygen atoms in NO2^- and NO3^- by adding H2O and OH^- to the appropriate sides of the equation:

NO2^- + H2O → NO3^- + OH^-

Finally, we balance the electrons by multiplying the Fe3+ reduction half-reaction by 2, and adding it to the oxidation half-reaction for NO2^-:

2Fe3+ + 2e^- → 2Fe2+

NO2^- + 2Fe3+ + 2H2O → NO3^- + 2Fe2+ + 2OH^-

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a) Moles of HCI that were needed is 14.88 mol  ; b) Grams of HCI that were needed is 670.14 g.

Equation where number of atoms of each element in the reactant is equal to the number of atoms of the same element in the products is called as the balanced equation.

a.) 30 g / 2.016 g/mol = 14.88 mol of H₂

From the balanced equation, we can see that one mole of H₂ is produced for every mole of HCl consumed. Therefore, the number of moles of HCl needed is also 14.88 mol.

b.) 2 moles of HCl are consumed for every mole of PbCl₂ produced

So, the number of moles of HCl needed to produce 9.2 moles of PbCl₂ is:

9.2 mol PbCl₂ × 2 mol HCl/mol PbCl₂ = 18.4 mol HCl

18.4 mol × 36.46 g/mol = 670.14 g of HCl

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Answer:

20.44 grams of sodium nitrate can be formed

Explanation:

The balanced chemical equation for the reaction between lead (II) nitrate and sodium iodide is:

Pb(NO3)2 + 2NaI → 2NaNO3 + PbI2

Diluting a solution increases the amount of ions in the solution and gives them more room to move about, which increases the mobility of the ions and raises the molar conductivity in the solution at the same time.

A solute dissolving agent, used to create homogenous mixtures. To create a homogenous mixture, a solute must dissolve in a solvent.Although solutions of both solids and gases are possible, the term "solution" is most frequently used to refer to the liquid condition of matter.

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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)

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.

Given the following standard enthalpies of formation for the following substances, H2O (g) = -241.8 kJ/mol KOH (aq)=-482.4 kJ/mol KOH(s) =-425.8 kJ/mol The enthalpy of the reaction is -390.2 kJ/mol.

The standard enthalpy of formation, also known as the standard heat of formation, is the change in enthalpy that occurs during the synthesis of one mole of a substance from its component parts in their reference states, with all substances in their standard states. The IUPAC recommends using the standard pressure value of p = 105 Pa (= 100 kPa = 1 bar), while previous to 1982, the value of 1.00 atm (101.325 kPa) was used.A standard temperature doesn't exist. Its designation is fH. This symbol's superscript Plimsoll denotes that the process has been carried out under typical circumstances at the given temperature (typically 25 °C or 298.15 K).

The enthalpy of the reaction can be calculated using Hess's Law and the standard enthalpies of formation for the reactants and products. First, we need to determine the enthalpy of the reaction, ∆Hrxn. This is the sum of the standard enthalpies of formation for the products minus the sum of the standard enthalpies of formation for the reactants.

∆Hrxn = [2(-482.4) kJ/mol + (-241.8) kJ/mol] - [2(-425.8) kJ/mol + (-285.8) kJ/mol]

∆Hrxn = -390.2 kJ/mol

Therefore, the enthalpy of the reaction is -390.2 kJ/mol.

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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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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: