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Which statement about the following reaction is correct?

CH4 (g) + 2O2 (g) yields CO2 (g) + 2H2O(l) deltaH = -890 kJ

reacting one mole of oxygen (O2) absorbs 445 kJ of energy
reacting one mole of oxygen (O2) releases 445 kJ of energy
reacting one mole of methane (CH4) absorbs 890 kJ of energy
reacting two moles of methane (CH4) releases 890 kJ of energy

Molarity is a concentration unit that is expressed as the number of moles of the solute per liter of solution. Only Option D (10 mol of solute/ 1L of solution) presents the solution concentration in terms of molarity.

In chemistry, molarity is a concentration unit that is expressed as the number of moles of the solute per liter of solution. In this context:
Option A represents a weight to weight percent concentration, not molarity.
Option B, though it seems similar to molarity, is not equivalent due to using mass (g) instead of moles for the solute.
Option C would be considered dilution, wherein the volume of a solution is increased, thus decreasing the solute's overall molarity.
Only Option D (10 mol of solite/ 1L of solution) directly aligns with the definition of molarity and represents the solution concentration in terms of molarity.

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Answer:

2.03125g of acetylene

Explanation:

First thing's first, we have to write out the balanced chemical equation;

CaC2(s) + 2H2O(l) → Ca(OH)2(aq) + C2H2(g)

Water is in excess, so CAC2 is our limiting reactant. i.e it determines the amount of product that would be formed.

1 mol of CaC2 produces 1 mol of C2H2

In terms of mass;

Mass = Number of moles * Molar mass

where the molar mass of the elements are;

Ca = 40g/mol

C = 12g/mol

H = 1g/mol

CaC2 = 40+ (2*12) = 64g/mol

C2H2 =( 2 * 12) + ( 2 * 1) = 26g/mol

64g (1 * 64g/mol) of CaC2 produces 26g ( 1mol * 26g/mol) of C2H2

5g would produce x?

64 = 26

5 = x

Upon solving for x we have;

x = (5 * 26) / 64

x = 2.03125g

By using a balanced chemical equation and molar conversions, we can calculate that adding water to 5.00 g of CaC2 will produce approximately 2.03 grams of acetylene.

In order to find out how many grams of acetylene are produced by adding water to 5.00 g of CaC2, we need to start by writing a balanced chemical equation for the reaction: CaC2(s) + 2H2O(l) → C2H2(g) + Ca(OH)2(aq). From this equation, we can see that one molecule of calcium carbide reacts with two molecules of water to produce one molecule of acetylene and one molecule of calcium hydroxide.

Next, we calculate the molar mass of CaC2 which is approximately 64 g/mol. Therefore, 5.00 g of CaC2 is approximately 0.0781 moles. According to the chemical equation, one mole of CaC2 produces one mole of C2H2, so 5.00 g of CaC2 would also produce 0.0781 moles of acetylene.

Last, we convert the moles of acetylene to grams by multiplying by its molar mass (26.04 g/mol), which gives us approximately 2.03 g of acetylene. Therefore, approximately 2.03 grams of acetylene are produced by adding water to 5.00 g of CaC2.

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The correct answer is; "The nucleus has a positive charge and is surrounded by negatively charged electrons"

The atom is composed of three particles, electrons, protons and neutrons.

The electrons are negatively charged, protons are positively charged while neutrons have no charge.

The protons and neutrons are housed in the nucleus of the atom. Since the protons are positively charged, the nucleus is regarded as being positively charged.

The nucleus is surrounded by negatively charged electrons.

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The compound  [tex]AlCl_3[/tex] is an ionic compound (metal and nonmetal) and therefore does not require prefixes so  [tex]AlCl_3[/tex] is aluminum chloride.

[tex]NCl_3[/tex] is a molecular compound (two or more nonmetals), and therefore in its name prefixes indicate the number of each type of atom so

[tex]NCl_3[/tex] is nitrogen trichloride.

                        cation name: potassium ion

                        anion name: chloride

                        compound name: potassium chloride

        mono - 1                         hexa - 6

        di - 2                               hepta - 7

        tri - 3                               octa - 8

        tetra - 4                           nona - 9

        penta - 5                         deca - 10

                        no. of carbon atom = 1 (mono-)

                        no. of oxygen atom = 2 (di-)

                        name of the compound: carbon dioxide

Keywords: nomenclature, ionic, molecular

AlCl3 is an ionic compound, which means that the aluminium cation and chlorine anion make up its structure. Strong electrostatic forces hold the two elements' strong ionic connection together.

Because of this, the compound's name just needs to include the prefix aluminium chloride. However, the substance NCl3 is a molecular molecule, which means that it is made up of two non-metals, namely nitrogen and chlorine.

Prefixes are needed in the name of this element to denote the number of each kind of atom present since the link between these two elements is weaker than the ionic interaction between aluminium and chlorine. Thus, the substance is sometimes referred to as nitrogen trichloride.

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Answer:

c

Explanation:

im doing it now and the answer above me is wrong

FeSO4 iron sulfate.

Iron(II) sulfate or ferrous sulfate denotes a range of salts with the formula FeSO₄·xH₂O. those compounds exist most typically as the heptahydrate but several values for x are known. The hydrated form is used medically to treat iron deficiency, and additionally for business applications.

Ferrous sulfate (or sulfate) is a medicine used to treat and prevent iron deficiency anemia. Iron allows the body to make healthy red blood cells, which deliver oxygen across the body. some matters such as blood loss, pregnancy, or too little iron in your diet could make your iron supply drop too low, leading to anemia

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Answer:

The amount of substance we need to recover 34.6 mol of carbon is 465.47g

Explanation:

we want to know what mass of substance we need to recover 34.6 mol of carbon

This substance is composed of 89.2% carbon

Wmust recover 34.6 mol of carbon and we know that the molecular mass of carbon is 12g / mol this means that one mole of carbon has a mass of 12 g

We use a simple rule of three to know how many grams of carbon are in 34.6 mol

[tex]1 mol C\longrightarrow 12g\\34.6 mol C\longrightarrow x\\x=\frac{(34.6)(12)}{1}= 415.2 g[/tex]

415.2 g are 34.6 mol of carbon

As the amount of carbon we want to recover is 415.2g (34.6mol)  and this amount corresponds to 89.2% of the total

To calculate the total mass we need we use a simple rule of three

[tex]89.2\%\longrightarrow 415.2 g\\100\%\longrightarrow x\\x=\frac{(100)(415.2)}{89.2}\\ x= 465.4g[/tex]

The amount of substance we need to recover 34.6 mol of carbon is 465.47g

Answer:

THE SAME NUMBER OF PROTONS

Explanation:

Elements in the same period or row will have the same number of electron shells. So the correct option is C.

The electron shell of an atom is the region that surrounds the atomic nucleus which contain a particular number of electrons. Each of the electron orbit allowed has been given a quantum number of n.

It can run from 1, which is for the orbit that is closest to the nucleus to infinity, which is for the orbits totally far from the nucleus. All of the orbitals that have the same value of n constitute an electronic shell.

Inside each of the atomic shells, there are also subshells. These correspond to the different rates of rotation and orientation of the orbitals and also to the directions of the spin of the electrons.

Generally, if the shell is far away from the nucleus or the value of n is higher, the number of subshells will also be higher.

Therefore the correct option is C.

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Answer: C

Explanation: Just took the test.

When 5.40 moles of ethane are burned in excess oxygen, 10.80 moles of carbon dioxide are produced.

The balanced chemical equation for the combustion of ethane (C₂H₆) in oxygen (O₂) is:

C₂H₆ + 7/2 O₂ -> 2 CO₂ + 3 H₂O

From the balanced equation, we can see that 1 mole of ethane (C₂H₆) produces 2 moles of carbon dioxide (CO₂) during combustion. This means that the mole ratio of ethane to carbon dioxide is 1:2.

Given that 5.40 moles of ethane are burned, we can use this mole ratio to calculate the moles of carbon dioxide produced:

5.40 moles of C₂H₆ x (2 moles of CO₂ / 1 mole of C₂H₆) = 10.80 moles of CO₂

So, when 5.40 moles of ethane are burned in excess oxygen, 10.80 moles of carbon dioxide are produced.

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Answer:

Backward direction

Explanation:

Exothermic reaction: It is that reaction in which heat is evolved during reaction.

We are given

[tex]H_2+Cl_2\rightleftharpoons 2HCl[/tex]

It is exothermic reaction.

We know that in exothermic reaction   when we increase the temperature then the equilibrium shift in backward direction and when we decrease the temperature then the equilibrium shift in forward direction.

Therefore, when we increasing the temperature then the equilibrium shift in backward direction.

Answer : The number of moles of carbon in the original sample were 0.166 moles.

Explanation :

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

[tex]C_xH_yO_z+O_2\rightarrow CO_2+H_2O[/tex]

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of [tex]CO_2=7.33g[/tex]

Mass of [tex]H_2O=3.00g[/tex]

We know that:

Molar mass of carbon dioxide = 44 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 7.33 g of carbon dioxide, [tex]\frac{12}{44}\times 7.33=1.99g[/tex] of carbon will be contained.

Now we have to calculate the moles of carbon.

Moles of Carbon =[tex]\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{1.99g}{12g/mole}=0.166moles[/tex]

Therefore, the number of moles of carbon in the original sample were 0.166 moles.

Answer:

Graphite.

Explanation:

Hello,

Graphite, plumbago or black lead, is a mineral making up of carbon as its main atom. It has an aromatic-like structure that consists of rings of six carbon atoms assembled in widely spaced horizontal planes. It is extremely soft, and slippery, cleaves at low pressure. Moreover has a very low specific gravity making it a decent electricity conductor. In addition, it successfully withstands heat.

Best regards.

Answer: Option (A) is the correct answer.

Explanation:

A transition element is defined as the element which has incompletely filled d-orbital.

For example, atomic number of chromium is 24 and its electronic configuration is [tex][Ar]4s^{1}3d^{5}[/tex].

Also, sometimes the s-orbital is completely filled and sometimes it is half-filled.

Hence, we can conclude that a single factor that classifies an element as a transition metal is that the  highest occupied orbital is a "d" orbital.

Nearsightedness or myopia is a condition where the person can see the near objects clearly but distant objects appears blurred. This eye condition is corrected with contact lenses or prescription eyeglasses. Another approach is LASIK or corrective eye surgery. In LASIK laser is used to correct the vision.  

The mole of oxygen needed to react with 6 moles of ethane is 1.16 mol.

Combustion reactions are those in which the substance react with oxygen and produce heat and light.

The reaction will be

[tex]\rm 2C_2H_6 + 7O_2 = 4CO_2 + 6H_2O[/tex]

Now,

[tex]1\; mole\;of \;ethane \times \dfrac{7\;mol\;ofO_2}{6\;mol\;of\;C_2H_6} = 1.16 mol[/tex]

Thus, the moles of oxygen is 1.16 mol.

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Final answer:

To react with 6 moles of ethane, 21 moles of oxygen would be needed.

Explanation:

To determine the number of moles of oxygen needed to react with 6 moles of ethane, we need to use the balanced chemical equation for the reaction. The balanced equation for the combustion of ethane is:

C2H6 + 3.5O2 → 2CO2 + 3H2O

From the balanced equation, we can see that 1 mole of ethane reacts with 3.5 moles of oxygen. Therefore, 6 moles of ethane would require:

(6 moles ethane) * (3.5 moles O2 / 1 mole ethane) = 21 moles of oxygen

Hydrogen bonds are approximately 5% of the bond strength of covalent bonds, for example (C-C or C-H bonds).
Hydrogen bonds strength in water is approximately 20 kJ/mol, strenght of carbon-carbon bond is approximately 350 kJ/mol and strengh of carbon-hydrogen bond is approximately 340 kJ/mol.
20 kJ/350 kJ = 0,057 = 5,7 %.

Final answer:

The strength of a hydrogen bond is approximately 5% that of a covalent bond. The correct answer is c. 5%.

Explanation:

The average strength of a hydrogen bond is approximately 5% of the average strength of a covalent bond. Therefore, the correct answer to the question is c. 5%. Hydrogen bonds are a type of intermolecular attractive force where a hydrogen atom covalently bonded to an electronegative atom is attracted to a lone pair of electrons on a neighboring molecule. While hydrogen bonds are much stronger than other dipole-dipole interactions, they are still significantly weaker than covalent bonds, but integral for holding together structures like DNA and proteins in biology.

Final answer:

To calculate the molarity of diluted aqueous solutions of HCl and KI, we apply the dilution formula M1V1 = M2V2, producing final molarities of 0.319 M for HCl and 1.37×10⁻² M for KI.

Explanation:

The question involves calculating the molarity of two different aqueous solutions after dilution. For both parts (a) and (b), we will apply the concept that molarity (M) is the number of moles of solute per liter of solution, and that the number of moles of solute remains constant during the dilution process, allowing us to use the equation M1V1 = M2V2, where M1 and V1 are the initial molarity and volume, respectively, and M2 and V2 are the final molarity and volume, respectively.

For the solution of HCl: Given an initial volume of 25.5 mL (or 0.0255 L) and molarity of 6.25 M, diluted to a final volume of 0.500 L, the final molarity (M2) can be calculated as follows:M2 = (M1 × V1) / V2 = (6.25 M × 0.0255 L) / 0.500 L = 0.319 M.

For the solution of KI: With an initial volume of 8.25 mL (or 0.00825 L) and molarity of 2.00×10⁻² M, diluted to a final volume of 12.0 mL (or 0.012 L), the final molarity is calculated similarly: M2 = (M1 × V1) / V2 = (2.00×10⁻² M × 0.00825 L) / 0.012 L = 1.37×10⁻² M.

401(k) and  Keogh plan both are  an example of a defined contribution plan and the correct option is option C.

A defined contribution (DC) plan is a retirement plan that's typically tax-deferred, like a 401(k) or a 403(b), in which employees contribute a fixed amount or a percentage of their paychecks to an account that is intended to fund their retirements.

In addition, the sponsor company can match a portion of employee contributions as an added benefit.

These plans place restrictions that control when and how each employee can withdraw from these accounts without penalties.

Therefore, 401(k) and  Keogh plan both are  an example of a defined contribution plan and the correct option is option C.

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