Help please and thank you

The true statements are;

The reaction is endothermic

Heat is a reactant

ΔHrxn is 89 kJ/mol

Enthalpy is a thermodynamic property that represents the total energy of a system, including both its internal energy (the energy of its constituent particles) and the energy it has due to its temperature and pressure. It is commonly used in energy analysis and heat transfer calculations and is expressed in units of joules (J) or calories (cal).

We know that the enthalpy of the reaction can obtained from;

Enthalpy of the products - Enthalpy of the reactants

ΔH reaction = 2(-391.4) - 2(-435.9)

(-782.8) - (-871.8)

= 89 kJ/mol

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Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. Therefore, the average atomic mass of copper is 63.55amu.

Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.

Average atomic mass = (mass of first isotope× percent abundance of first isotope)+(mass of second isotope× percent abundance of second isotope)

Substituting the given values, we get

Average atomic mass=(  62.96  amu × 70.5% )+(64.96 amu ×29.5% )

Average atomic mass=55.58+12.27

Average atomic mass=63.55amu

Therefore, the average atomic mass of copper is 63.55amu.

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The half equation for this reaction is 2H2 + O2 = 2H2O and this is reduction because it is taking place in cathode.

Does cathode or anode decrease occur?

Although the direction of spontaneous electron flow in galvanic cells may be reversed in electrolytic cells, the definitions of cathode and anode where reduction takes place at the cathode and oxidation happens at the anode remain the same.

Which ions undergo cathodic reduction?

The positively charged ions will migrate toward the cathode after becoming reduced by receiving electrons. Since positive ions pick up electrons at the negative cathode, reduction takes place there.

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False, using changes in tempo and dynamics can make a musical cliché more effective. Hence, option C is correct.

Tempo in a music refers to pace of the music especially in high pitch sound waves. The most common unit of measurement for tempo is beats per minute (BPM), which is just the quantity of beats that may be captured in a minute at a certain pace.

A musical segment or composition is slower when the beats per minute  is lower than when the BPM is greater. While a higher BPM is more likely to make the listener feel excited, a lower BPM is more likely to have a calming and/or sad effect on the listener.

Changing dynamics is some more effective way to make musical cliché. Hence, option C is correct.

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Ca(C2H3O2)2 has 30.41% carbon by volume, according to calculations.

By dividing the atomic mass of the element by the molar mass of the compound, then by 100%, one can get the percentage of the element in a compound.

The percentage form of the mixture is obtained by multiplying this ratio by 100.

By dividing the atomic mass of the element by the molar mass of the compound, then by 100%, one can get the percentage of the element in a compound.

Atomic mass of C divided by the molar mass of Ca(C2H3O2) yields the percentage of carbon.

₂ × 100%

Ca(C2H3O2)2 has an atomic mass of 40 plus (24 plus 3 plus 32).

2 = 158g/mol \s % C = 12.01(4)/158 × 100 \s % C = 30.41%.

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Answer:

To convert from Kelvin to Celsius, subtract 273 and vice versa to convert from Celsius to Kelvin.

Therefore:

298K - 273 = 24 °C

5°C + 273 = 278K

335K - 273 = 62°C

An electron get from one lobe of a p orbital because of the wave behavior of the p- orbital, electrons do not cross through the node or point of zero electron density when traveling from one lobe (positive lobe) to the other lobe (negative lobe).

The effective nuclear force of attraction is lower with p orbital electrons than with s orbital electrons. As a result, removing an electron from the s orbital requires more energy than removing an electron from the p orbital.

One orbital maximum can have two electrons. Because the s sublevel has only one orbital, it can only hold two electrons. Because the p sublevel has three orbitals, it can hold a maximum of six electrons.

Thus, Electrons can move out between orbits by releasing or absorbing energy.

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The units are kilojoules and calorie are used to express the energy o a system. One kJ  is 0.239 cal. Using this relation, we can convert kJ to calorie.

Energy of a system is equivalent to  the work done on the system or by the system using a force applied. The SI unit of work and energy is joule (J). One J of energy is the basic unit.

1000 joules = one kilojoule.

Other units of energy are, calorie, erg etc. The relation between one kJ and calorie unit is:

1 kJ = 0.239 calories.

Using this relation we can interconvert these two units.

For example, 20 KJ of energy is converted to calories as:

20 kJ  × 0.239 cal / 1 kJ =  4.78 calories.

Therefore, kJ of energy can be converted to cal by multiplying with 0.239.

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A black precipitate is formed by the reaction; Li2S(aq) + Pb(NO3)2(aq) ------> PbS(s) + 2LiNO3(aq) and K2S(aq) + Sn(NO₃)₄(aq)→ SnS(s) + KNO₃(aq)

In a twofold decomposition reaction, the cations swap out their anion companions to form the final product. A precipitate can sometimes be produced by a twofold decomposition reaction.

A precipitate is a solid byproduct of an aqueous species reaction.

Hence, a black precipitate is formed by the reaction; Li2S(aq) + Pb(NO3)2(aq) ------> PbS(s) + 2LiNO3(aq) and K2S(aq) + Sn(NO₃)₄(aq)→ SnS(s) + KNO₃(aq)

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Insoluble sulfide compounds are generally black in color.

Which of the following combinations could yield a black precipitate?

Na2S(aq)+KCl(aq)

Li2S(aq)+Pb(NO3)2(aq)

Pb(ClO3)2(aq)+NaNO3(aq)

AgNO3(aq)+KCl(aq)

K2S(aq)+Sn(NO3)4(aq

The liquid in Titan's lake is believed to be composed of liquid methane and ethane, which are thought to be supplied by geological processes such as cryovolcanism and seepage from the surrounding terrain. Over time, the liquid in Titan's lake can evaporate, change due to geological or meteorological processes, or be affected by the changing seasons on the moon.

Based on the table above, the food chain Sun → grass → ground squirrel → coyote  most likely present in the prairie ecosystem. Therefore, the correct option is option B.

An ecosystem may be divided into its biotic constituents, which include all of its living members, and its abiotic constituents, which include minerals, the environment, soil, water, sunshine, and any other nonliving elements. The movement of energy through into the ecosystem as well as the cycle of nutrients inside the ecosystem are the two main factors that bind these components together.

The table below shows the organisms in a prairie ecosystem. It also shows where they get energy from. Based on the table above, the food chain Sun → grass → ground squirrel → coyote  most likely present in the prairie ecosystem.

Therefore, the correct option is option B.

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In nature, oxygen exists as a molecule. To create dioxygen, or O2, two oxygen atoms must make a covalently double bond with one another. Typically, oxygen exists as a molecule. It has the name dioxygen.

Its original definition, "the simplest form of a substance which still maintains the properties of the that substance," was intended to be encompassed by this name. "An atom is a body that can't be cut in 2; a molecule is the littlest portion of the a particular substance," wrote James Maxwell in 1873 when defining atom and molecule. Since ...

According to the contexts, this word might or might not include ions that meet this requirement. A molecule is a collection of atoms that are held together by the force of attraction known as chemical bonds.

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The number of moles of hydrogen gas produced from 1.2 g of water is 0.06 moles. Then, the partial pressure of hydrogen gas is 4.9 atm.

The partial pressure of a gas in a mixture is the contribution of the gas to the total pressure of the mixture.

The molar mass of water = 18 g/mol

mass = 1.2 g

number of moles  = 1.2/18 =0.06 moles.

now the total pressure p = nRT/v

V = 0.20 L

T = 30°C =303 K

then  p = (0.06 mol × 0.082 L atm/ K mol × 303 K) / 0.20 L = 7.4 atm.

Now, 2 moles of water gives 2 moles of hydrogen gas and one mole of oxygen. Then 0.06 moles of water gives 0.06 moles of hydrogen and 0.03 moles of oxygen.

Then, mole fraction of hydrogen = 0.06/(0.03 + 0.03) = 0.66.

Partial pressure of hydrogen = total pressure × mole fraction

= 0.66 × 7.4 atm = 4.9 atm.

Therefore, the partial pressure of hydrogen gas is 4.9 atm.

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The mass of sulfur in a sample of CaSO4 with a mass of 67.0 g would be 15.73 grams.

11.5 grams of CaSO4 contains 3.39 grams of Ca and 5.41 g of O.

Mass of sulfur = 11.5 - (3.39 + 5.41) = 2.7 grams

11.5 grams of CaSO4 contains 2.7 grams of sulfur. The mass of sulfur in 67.0 grams of CaSO4 can be estimated as:

11.5 grams CaSO4 = 2.7 grams S

67.0 grams CaSO4  = 67.0 x 2.7/11.5

                                 = 15.73 grams

In other words, if 11.5 grams of CaSO4 contains 2.7 grams of S, then 67.0 grams will contain 15.73 grams of sulfur.

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Hydrogen gas and zinc chloride are quickly formed when zinc and hydrochloric acid interact. It is a single displacement reaction: Zn (s)+2HCl(aq), ZnCl2(aq), and H2 (g).

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4.4 a. The metal that the main part of the garden fork has been made from is iron. The correct option is B

b. The chemical name for rust is hydrated iron (iii) oxide

c. One way of preventing the fork from rusting is by painting the fork.

4.5 Based on the given equations;

a. the equation that produces a metal oxide is equation D.

b. the equation that is a neutralization reaction is equation B.

c. the equation that is a burning reaction is equation A.

The complete equation for the given equations are:

d. sodium + water → sodium hydroxide + hydrogen

e copper carbonate + sulfuric acid → copper sulfate + carbon dioxide + water

f. sulfur + oxygen → sulfur dioxide

Rust is an iron oxide, a typically reddish-brown oxide created when iron and oxygen react catalytically with moisture from the air or water.

Iron(III) oxide-hydroxide and hydrated iron(III) oxides make up rust, which is often linked to the corrosion of refined iron.

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Beta decay will occur in isotopes with a N/Z ratio greater than 1, which translates to an overabundance of neutrons.

Beta decay produces a new element that has one more proton and one fewer neutron while alpha decay produces a new element with some less protons and two fewer neutrons. When a nucleus from a higher energy state descends to a lower energy state and releases the excess energy through to the emission of high energy photons, this process is known as gamma decay.

Any one of three radioactive disintegration processes known as beta decay occurs when some unstable atoms spontaneously release surplus energy and undergo a shift in one unit of positive ions without changing their mass number.

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Answer: 33.2 micrograms

Explanation:

We are going to convert grams to micrograms.

Step 1

Determine the conversion factors to use for converting grams to micrograms.

1 gram = 1000 milligrams

1 milligram = 1000 micrograms

Step 2

Use the number in the problem and the conversion factors to set up the problem so all conversion factors cancel except micrograms.

3.32 x 10⁻⁵ grams x (1000 milligrams/1 gram) x (1000 micrograms/1 milligram) = 33.2 micrograms/1 = 33.2 micrograms

Note that grams and milligrams cancel and you are left with micrograms. The given quantity 3.32 x 10⁻⁵ grams has 3 significant figures, so the final answer should have 3 significant figures too.

Newton's first law states that unless acted on by an unbalanced force, an object will remain at rest or move at a constant speed in a straight line. To move the book on your desk, Newton's first law requires an unbalanced force.

The First Law of Motion of Newton (Inertia) Unless acted on by an unbalanced force, an object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line.

When an unbalanced force acts on an object, the object's motion changes. The object's speed or direction may change. Friction is a force that opposes motion or the tendency for motion between two objects in contact.

Thus, an object will remain at rest or move at a constant speed in a straight line.

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Answer: 0.112 atm.

Explanation:

(PV = nRT), which states that the pressure times volume of a gas is equal to the number of moles of gas times the ideal gas constant times the temperature.

Since the volume of the bottle is constant, we can rearrange the Ideal Gas Law to solve for pressure:

P = (nRT) / V

where

n = 0.000540 moles (the amount of O2 remaining after the candle goes out)

R = 8.31 J/mol*K (the ideal gas constant)

T = 35 + 273 = 308 K (the temperature in kelvins)

V = 250 mL = 0.25 L (the volume of the bottle in liters)

Plugging in the values, we get:

P = (0.000540 * 8.31 * 308) / 0.25

P = 0.112 atm

So, the pressure inside the bottle after the candle goes out is approximately 0.112 atm.

The intermolecular force present in butter is London dispersion forces. In kerosene, covalent bonding between carbon and hydrogen atoms are present.

Intermolecular forces are force exerted between two molecules which can be of attraction or repulsion. The intermolecular force of attraction make the atoms binded in a compound or molecule.

In butter, the hydrocarbon molecules exerts a London dispersion forces between two non-polar molecules. In kerosene, the hydrocarbon molecules are bound by covalent bonding between carbon atoms.

In ethanol, the OH group make it possible to form hydrogen bonds between ethanol molecules. In the case of calcium fluoride, dipole, dipole forces exists. Since the compound is ionic and have a permanent dipole moment.

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As per the balanced reaction, 4 moles or 156 g of potassium produces 2 moles or 188 g of K₂O. Hence, the mass of K required to produce 23.5 g of K₂O is 19.5 g.

Alkali metals such as sodium and potassium forms superoxide having the general formula, M₂O. These metals easily reacts with atmospheric oxygen forms their oxides.

The given reaction shows that, 4 moles of K gives 2 moles of K₂O.

atomic mass of K = 39 g/mol

mass of 4 K = 4 × 39 = 156 g

molar mass of K₂O = 94 g

mass of 2 moles = 188 g.

Hence, 156 g of K gives 188 g of potassium oxide. Thus, mass of K required to produce 23.5 g  is:

(23.5 × 156)/188 = 19.5 g.

Therefore, 19.5 g of potassium metal is required to produce 23.5 g of K₂O.

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Explanation:

The atomic mass of gallium for this location can be calculated using the following formula:

Atomic mass = (69^Ga abundance x 69^Ga mass) + (71^Ga abundance x 71^Ga mass)

Plugging in the values:

Atomic mass = (0.6011 x 68.7200 amu) + (0.3989 x 70.9200 amu) = 41.4762 amu + 28.2957 amu = 69.7719 amu

Therefore, the atomic mass of gallium for this location is 69.77 amu.

The ion concentration of 0.05 M [tex]CaCl_2[/tex] would be 0.05 mol Ca ions and 0.1 mol Cl ions respectively.

[tex]CaCl_2[/tex] contains two ions according to the following equations:

[tex]CaCl_2 -- > Ca^{2+} + 2Cl^-[/tex]

1 mole           1 mole   2 moles

0.05 M CaCl2 contains 0.05 moles of the solute in 1 liter of the solution. Thus, the equivalent mole of Ca ion would be 0.05 moles while that of Cl ion would be 0.10 mole (0.05x2).

Concentration of Ca ions = 0.05 moles

Concentration of Cl ions = 0.05 x 2 = 0.010 moles

In other words, the ion concentrations of 0.05 M CaCl2 would be 0.05 moles of Ca ions and 0.10 moles of Cl ions.

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Answer: Henry's law states that the solubility of a gas in a liquid is proportional to the partial pressure of the gas over the solution. The relationship can be represented by the equation:

C = kP

where C is the concentration of the gas (in mol/L), k is the Henry's law constant, and P is the partial pressure of the gas.

Given that the mole fraction of oxygen in water is 0.210, the partial pressure of oxygen in the solution is:

P = 0.210 * 1 atm = 0.210 atm

Since the Henry's law constant for oxygen at 25 ∘C is 1.3 × 10^(-3) M/atm, the concentration of oxygen in water can be calculated as:

C = 1.3 × 10^(-3) M/atm * 0.210 atm = 0.000276 M

Finally, the mass of oxygen dissolved in 120.0 L of water can be calculated as:

mass = C * volume * molecular weight of oxygen

= 0.000276 M * 120.0 L * 32.0 g/mol

= 10.57 g

Explanation:

Electrons are transferred from atoms of sodium to atoms of phosphorous The sodium atom looses electron and the phosphorus atoms gains electrons.

The electron is a subatomic particle with an elementary electric charge of -1. Electrons are the first generation of the lepton particle family and are widely regarded as elementary particles due to the lack of known components or substructure.

This transfer causes the sodium atoms  to acquire positive charge and phosphorous to acquire negative charge .

Thus, the sodium and phosphorus atoms strongly attract with each other.

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Your question is incomplete, most probably, your question was

Complete the paragraph about the formation of sodium phosphide.

Electrons are transferred from atoms of

and the phosphorus atoms

to atoms of

C. This transfer makes the sodium atoms

As a result, the sodium and phosphorus atoms strongly

each other.

A + BC → AB + C "single replacement reaction" while ammonia synthesis is a "synthesis reaction".

A single replacement reaction is a reaction by which one element replaces an/another element in a compound.

It can be represented generically as: A + B-C → A-C + B This will most often occur if A is more reactive than B, thus giving a more stable product.

A chemical reaction known as a synthesis occurs when two or more simple chemicals combine to create a more complex result. The result is always a chemical, while the reactants can be either elements or other compounds.

Example: ammonia synthesis,

N₂ + 3H₂ ⇄ 2NH₃

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The heat of solution for 10.5 g of potassium perchlorate dissolved in 113.8 mL of water is approximately -83.99 kJ/10.5 g.

The heat of solution is described as the enthalpy change associated with the dissolution of a substance in a solvent at constant pressure resulting in infinite dilution.

For 10.5 g of potassium perchlorate dissolved in 113.8 mL of water, the amount of heat released can be estimated as follows:

-599 kJ/mol x (10.5 g / 138.55 g/mol) = -44.31 kJ

-548 kJ/mol x (10.5 g / 138.55 g/mol) = -39.68 kJ

The heat of solution for potassium perchlorate will then be calculated as the sum of the lattice energy and heat of hydration which gives us that

Heat of solution = -44.31 kJ + -39.68 kJ = -83.99 kJ/10.5 g

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The osmotic pressure of the protein solution is given 3.54 torr or 0.004 atm. Then, the molar mass of the protein is 7222 g/mol.

The pressure required to stop the flow or diffusion of  solvent molecules through a semipermeable membrane is called osmotic pressure. The osmotic pressure is represented as π and is related to the pressure, volume and number of moles as follows:

π  = n RT

given π = 3.54 torr = 0.004 atm

volume v = 23 ml  = 0.023 L

temperature = 27 °C = 300 K

R = 0.082 L atm/ K mol

then, n = π V/RT

n = 0.004 atm ×0.023 L /(0.082 L atm/ K mol × 300 K)

  = 3.69× 10⁻⁹.

weight of the protein sample = 26.75 mg = 0.026 g

then, molar mass =   0.026 g/ 3.69× 10⁻⁹mol  = 7222 g/mol

Therefore, the molar mass of the protein sample is 7222 g/mol.

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