What is the concentration in parts per million? Assume the density of the solution is the same as that for pure water (1.00 g/mL). ppm

Answer:

Covalent bond

Explanation:

Functional groups can be defined as a group of atoms or ions responsible for the properties particular to a certain group of organic compounds. What we are saying in essence is that it is the functional groups that decides the behavior of the organic compound in question.

Covalent linkages are the mechanism through which these functional groups are linked to the carbon skeleton of the compound to which they belong. Covalent bonding is a type of chemical bonding which in there is sharing of electrons between atoms

Covalent bond

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Explanation:

The mass of carbon and hydrogen is calculated from the mass of their oxides ([tex]CO_{2}[/tex] and [tex]H_{2}O[/tex]) as follows.

    Mass of C = [tex]3.00 g CO_{2} \times \frac{12.01 g C}{44.0 g CO_{2}}[/tex]

                      = 0.818 g C

    Mass of H = [tex]1.23 g CO_{2} \times \frac{2.016 g H}{18.02 g H_{2}O}[/tex]

                      = 0.137 g H

So, the mass of C + mass of H is as follows.

                        0.818 g + 0.137 g = 0.955 g

This mass is actually less than the mass of sample. And, the missing mass must be caused by O. Hence, the mass of O will be calculated as follows.

            Mass of O = 1.50 g - 0.955 g

                              = 0.545 g

Now, we convert masses to moles and find their moles and ratio as follows.

  Element     Mass/g      Moles    Ratio    [tex]\times 2[/tex]     Integers

       C             0.818       0.068       1        2              2

       H             0.137        0.068      1        2               2

       O             0.545       0.0340    0.5   1                1

Thus, we can conclude that simplest formula for the given compound is [tex]C_{2}H_{2}O[/tex].

Answer:

C2H4O (ut quest)

Answer:

108.25 ºC

Explanation:

The boiling point elevation for a given solute in water is given by the expression:

ΔTb = i Kbm

where ΔTb is the boiling point elevation

           i is the van´t Hoff factor

           Kb the boiling constant which for water is 0.512 ºC/molal

           m is the molality of the solution

The molality of the solution is the number of moles per kilogram of solvent. Here we run into a problem since we are not given the identity of the coolant, but a search in the literature tells you that the most typical are ethylene glycol and propylene glycol. The most common is ethylene glycol and this it the one we will using in this question.

Now the i factor in the equation above is 1 for non ionizable compounds such as ethylene glycol.

Our equation is then:

ΔTb =  Kbm

So lets calculate the molality and then ΔTb:

m = moles ethylene glycol / Kg solvent

Converting gal to L

4.90 g x 3.785 L/gal = 18.55 L

in a 50/50 blend by volume we have 9.27 L of ethylene glycol, and 9.27 L of water.

We need to convert this 9.27 l of ethylene glycol to grams assuming a solution density of 1 g/cm³

9.27 L x 1000 cm³ / L = 9273.25 cm³

mass ethylene glycol = 9273.25 cm³ x 1 g/cm³ = 9273.25 g

mol ethylene glycol = 9273.25 g/ M.W ethylene glycol

                                 = 9273.25 g / 62.07 g/mol =149.4mol

molality solution =  149.4 mol / 9.27 Kg H₂O = 16.12 m

( density of water 1 kg/L )

Finally we can calculate ΔTb:

ΔTb =  Kbm = 0.512  ºC/molal x 16.12 molal = 8.25 ºC

boiling point = 100 º C +8.25 ºC = 108.25 ºC

( You could try to solve for propylene glycol the other popular coolant which should give around 106.7 ºC )

Answer:

Question 1

B) Volume decreases

Question 2

A) Higher pressure

Question 3

A and B

Explanation:

Question 1

B) Volume decreases

Charles' Law: The Temperature-Volume Charles Law. It states that at constant pressure, the volume of a given amount of gas is directly proportional to temperature in Kelvin. As the temperature goes down, the volume also goes down, and vice-versa.

ogadro's law states that "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules." For a given mass of an ideal gas, the volume and amount (moles) of

Question 2

A) Higher pressure

Avogadro's law states that "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules." For a given mass of an ideal gas, the amount (moles) and the volume of the gas are directly proportional at constant temperature and pressure

Increasing the number of moles increases the volume to maintain the same volume of the container with less moles the gas has to be compressed, increasing its pressure

Boyle's law is a gas law, that states that at constant temperature, the pressure and volume of a gas are inversely proportional. increasing the volume , decreases the pressure and vice versa.

Question 3

A and B

A) Doubling pressure while keeping temperature constant. B) Doubling absolute temperature while keeping pressure constant.

The volume of a given mass of gas decreases as pressure increases but increases as absolute temperature increases.

In the first question, a helium balloon initially at room temperature is dunked into a bucket of liquid nitrogen, the volume of the immediately decreases because volume and absolute temperature are directly proportional according to Charles law.

In the second question, two separate containers A and B have the same volume and temperature, but container A has more gaseous molecules than B, then container A will have higher pressure because the pressure of a gas is directly proportional to the number of molecules of a gas present.

In the third question, the change that would cause the volume of a gas to double, assuming moles were held constant is doubling absolute temperature while keeping pressure constant. This follows from Charles law where the volume of a given mass of gas is directly proportional to its volume at constant pressure.

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Answer:

glucose

Explanation:

Starch -

Starch is generated by the plants , and is a granular , white , organic compound .

The general formula of the starch is (C₆H₁₀O₅)ₙ , the n shows it to be a polymer , and it is composed of small monomers of glucose , that are linked  at the alpha 1 , 4 linkages.

Starch is is colorless , and tasteless powder.

The most simplest form of starch is the linear polymer amylose , and the branched one amylopectin.

Answer:

80 liters

Explanation:

At STP, 1 mole of ideal gas has a volume of 22.4 liters.

Therefore, since liters and moles are directly proportional, we can use stoichiometry directly.

40L CH₄ × (2L H₂ / 1L CH₄) = 80L H₂

Answer:

5290.7 kg of Al₂O₃ are produced in the reaction of 2800 kg of Al

Explanation:

The reaction to produce alumina is:

4 Al  +  3O₂  →  2 Al₂O₃

So, let's convert the mass of Al to moles (mass / molar mass)

2800 kg = 2800000 g (Then, 2.8 ×10⁶ g)

2.8 ×10⁶ g / 26.98 g/mol = 103780.5 moles of Al

Ratio is 4:2, so with the moles I have, I will produce the half of moles of alumina.

103780.5 mol / 2 = 51890.25 moles of Al₂O₃

Now we can convert these moles to mass ( molar mass . mol )

101.96 g/mol . 51890.25 mol = 5290729.8 g

5290729.8 g →  5290.7 kg

The mass of alumina Al₂O₃ formed from the reaction between Aluminum and oxygen is 5290.73 kg

The equation for the reaction that leads to the formation of alumina(Al2O3) can be expressed as:

[tex]\mathbf{2Al + \dfrac{3}{2}O_2 \to Al_2O_3}[/tex]

Given that:

the mass of aluminium Al = (2800 kg = 2800 × 1000) grams

= 2800000 grams

The molar mass of Aluminium Al = 26.98 g/mol

Number of moles of Al = 2800000 g/ 26.98 g/mol

Number of moles of Al = 103780.5782 moles

Since the ratio of the aluminium in the reactant and product is 2:1  

There will be half moles of alumina;

∴

Moles of alumina will be:

[tex]\mathbf{\dfrac{1}{2} \times 103780.5782 \ moles}[/tex]

= 51890.2891 moles of Al₂O₃

Mass = number of moles × molar mass

The molar mass of Al₂O₃  = 101.96 g/mol

Mass of  Al₂O₃= 51890.2891 g × 101.96 g/mol

Mass of  Al₂O₃ = 5290733.877 grams

Mass of  Al₂O₃ = (5290733.877/1000 ) kg

Mass of  Al₂O₃ = 5290.73 kg

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Option C, which involves adding 0.1M NaOH to quench unreacted anhydride, then adding diethyl ether and separating the layers, is the extraction procedure that will completely separate an amide from the by-product of the reaction between an amine and excess carboxylic acid anhydride.

The extraction procedure that will completely separate an amide from the by-product of the reaction between an amine and excess carboxylic acid anhydride is option C. First, you would add 0.1M NaOH (aq) to quench unreacted anhydride. Then, you would add diethyl ether and separate the layers. The amide can be obtained from the aqueous layer by neutralizing with HCl (aq).

Answer:

Option A, The Rutherford experiment proved the Thomson "plum-pudding" model of the atom to be essentially correct.

Explanation:

Thomson's plum pudding model:

Plum pudding model was proposed by J.J Thomson. In Thomson's model, atoms are proposed as sea of positively charge in which electrons are distributed through out.

Result of Rutherford experiment:

As per Rutherford's experiment:

Most of the space inside the atom is empty.

Positively charge of the atom are concentrated in the centre of the atom known as nucleus.

Electrons are present outside the nucleus and revolve around it.

As it is clear that, result of Rutherford experiment did not supported the Thomson model.

The Rutherford experiment did not prove the Thomson 'plum-pudding' model of the atom to be essentially correct. Instead, it disproved this model by showing that atoms have a small, dense, positively charged nucleus.

The statement 'The Rutherford experiment proved the Thomson 'plum-pudding' model of the atom to be essentially correct.' (option A) is not accurate. In fact, the Rutherford experiment disproved the Thomson 'plum-pudding' model of the atom. Rutherford's experiment revealed that atoms have a small, dense, positively charged nucleus, contradicting Thomson's model which proposed that positive charge was spread evenly throughout the atom. All other listed experiments (options B, C, and D) did indeed provide the results described.

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Answer : The change in enthalpy of the coffee is negative.

Explanation :

Endothermic reaction : It is defined as the chemical reaction in which the energy is absorbed from the surrounding.

In the endothermic reaction, the energy of reactant are less than the energy of product.

Exothermic reaction : It is defined as the chemical reaction in which the energy is released into the surrounding.

In the exothermic reaction, the energy of reactant are more than the energy of product.

Enthalpy change : It is the difference between the energy of product and the reactant. It is represented as [tex]\Delta H[/tex].

As per question, if hot coffee sits on your desktop and loses 50 kJ of energy during cooling, the change in enthalpy of the coffee is negative.

Hence, change in enthalpy of the coffee is negative.

Answer:

57.478atm

Explanation:

T = 400k

n = 5mol

v = 2.00

a = [tex]6.49L^{2}[/tex]

b = 0.0652L/mol

R = 0.08206

Formula

P =  [tex]\frac{RT}{(\frac{v}{n} )-b} - \frac{a}{(\frac{v}{n} )^{2} }[/tex]

[tex]P = \frac{0.08206 * 400}{(\frac{2.00}{5.00} )-0.0652} - \frac{6.49}{(\frac{2.00}{5.00} )^{2} }[/tex]

[tex]P = \frac{32.824}{0.3348} - \frac{6.49}{0.16}[/tex]  

[tex]P = 98.041 - 40.563[/tex]

[tex]P = 57.478atm[/tex]

The van der Waals equation, which accounts for the actual volume of gas molecules and the attractions between them, can be used to find the pressure of a 5.00 mol sample of Cl₂ at 400.0 K in a 2.00 L container.

The pressure of a 5.00 mol sample of Cl₂ at 400.0 K in a 2.00 L container can be found using the van der Waals equation. The van der Waals equation is a modification of the ideal gas law that takes into account the volume of the gas molecules themselves (represented by the parameter 'b') and the attractions between gas molecules (represented by 'a').

In this problem, the values of 'a' and 'b' for Cl₂ are given to be 6.49 L²･atm/mol² and 0.0652 L/mol respectively. The van der Waals equation is given by:

[P + a(n/V)²] (V/n - b) = RT

where P is the pressure we are trying to find, n is the number of moles of gas, V is the volume of the container, R is the gas constant (0.0821 L･atm/mol･K), and T is the temperature in kelvins. Substituting given values into this equation and simplifying it, we get the value of the pressure. Please note, this type of problem often requires some algebraic manipulation.

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Answer:

Option 3.

364.1 g of CO₂ are produced by the reaction

Explanation:

Let's verify the balance equation for this reaction:

Fe₃O₄  +   4 CO  →  3 Fe   +   4CO₂

Let's convert the mass of Fe₃O₄ to moles (mass / molar mass)

478.9 g / 231.55 g/mol  = 2.07 moles

Ratio is 1:4, so let's make a rule of three to determine the moles of CO₂ produced and then its mass.

1 mol of Fe₃O₄ is needed to produce 4 moles of CO₂

Then, 2.07 moles of Fe₃O₄ will produce (2.07  .4) /1 = 8.27 moles of CO₂.

Molar mass . moles = mass

44 g/mol . 8.27 mol = 364 g of CO₂

Answer:

The answer to your question is 4.07 x 10²² atoms

Explanation:

Process

1.- Get the molecular weight of Cocaine hydrochloride

C = 12 x 17 = 204 g

H = 22 x 1 = 22 g

Cl = 36 x 1 = 36 g

N = 14 x 1 = 14 g

O = 16 x 4 = 64 g

Molecular mass = 340 g

2.- Calculate the moles of the mass given

                             340 g -------------------  1 mol

                               23 g -------------------  x

                              x = (23 x 1) / 340

                              x = 0.068 moles of Cocaine

3.- Calculate the atoms

                            1 mol -------------------- 6 .023 x 10 ²³ atoms

                   0.068 moles -------------  x

                              x = (0.068 x 6.023 x 10²³) / 1

                              x = 4.07 x 10²² atoms

Answer:

Basic

Explanation:

The titration of a strong base with a weak acid would always result in a solution whose pH is greater than 7,i.e a basic solution. For this reason its advisable to use an indicator whose color change will occur in that pH range.

For other cases, the titration of a stong acid and strong will result in a neutral solution and the titration of a weak base versus a strong acid would result in an acidic solution.

Final answer:

At the equivalence point in a titration between a weak acid and a strong base, the solution will be basic due to the formation of a conjugate base from the weak acid which then increases the OH- concentration.

Explanation:

When performing a titration involving a weak acid and a strong base, the resulting solution at the equivalence point will typically be basic. This is due to the fact that the weak acid has a less complete dissociation in water compared to a strong base. At the equivalence point, a weak acid has been completely neutralized by the strong base, which means it has converted to its conjugate base by losing a proton. The conjugate base may then react with water to form OH- (hydroxide ions), making the solution basic.

Indicators are chosen according to the expected pH at the equivalence point. When titrating a weak acid with a strong base, an indicator that changes color in the basic pH range would be suitable, such as phenolphthalein. It is importantly noted that in a titration of a strong acid with a strong base, the equivalence point occurs at a neutral pH of 7.00; however, this is not the case for a titration involving a weak acid.

Answer:

For 0.353 moles AgNO3, we'll have 0.353 moles AgCl

Explanation:

How many moles of AgCl will be produced from 60.0g AgNO3 assuming NaCl is available in excess.

Step 1: Data given

Mass of AgNO3 = 60.0 grams

Molar mass AgNO3 = 169.87 g/mol

NaCl is in excess, so AgNO3 is the limiting reactant

Step 2: The balanced equation

AgNO3 + NaCl → AgCl + NaNO3

Step 3: Calculate moles AgNO3

Moles AgNO3 = mass AgNO3 / molar mass AgNO3

Moles AgNO3 = 60.0 grams / 169.87 g/mol

Moles AgNO3 = 0.353 moles

Step 4: Calculate moles AgCl

For 1 mol AgNO3 we need 1 mol NaCl to produce 1 mol AgCl and 1 mol NaNO3

For 0.353 moles AgNO3, we'll have 0.353 moles AgCl

Final answer:

To find the moles of AgCl produced from a reaction, calculate using stoichiometry and molar mass.

Explanation:

To determine the moles of AgCl produced:

Step 1: Data given

Mass of AgNO3 = 60.0 grams

Molar mass AgNO3 = 169.87 g/mol

NaCl is in excess, so AgNO3 is the limiting reactant

Step 2: The balanced equation

AgNO3 + NaCl → AgCl + NaNO3

Step 3: Calculate moles AgNO3

Moles AgNO3 = mass AgNO3 / molar mass AgNO3

Moles AgNO3 = 60.0 grams / 169.87 g/mol

Moles AgNO3 = 0.353 moles

Step 4: Calculate moles AgCl

For 1 mol AgNO3 we need 1 mol NaCl to produce 1 mol AgCl and 1 mol NaNO3

For 0.353 moles AgNO3, we'll have 0.353 moles AgCl

Answer:

The answer is B. False

Explanation:

The ratio of sizes between the ionic radii of cations and anions in a cell influences the manner of packing for that cell thereby predicting the possible cation/anion coordination number in any compound and establishing the structure of ionic solids.

Answer:

The explanation is given below

Explanation:

Toxicity is a measure of how harmful a substance is on a living organism (causing illness, injury or even death). There are several factors that must be considered when evaluating toxicity:

- Dose of exposure: the amount of substance to which the organism has been exposed to;

- Frequency of exposure: how many times (and for how long) the individual has been exposed to the substance;

- Age and health condition of the individual exposed;

- Genetic makeup: the genetic backgroun of an organism will determine its response and degree of sensitivity to a given substance.

Moreover, there are five main characteristics of substances that determine its toxicity: Solubility (hidrophilic or lipophilic substances), persistence (for how long the substance remains the same and cause the same damage), bioaccumulation (when the substance is progresivelly incorporated in tissues), biomagnification (when the amount of substance rise along trophic levels) and other chemical interactions (different interactions with other chemicals can increase the degree of damage) .  

The Rydberg formula can calculate the wavelengths of light emitted by hydrogen atoms. However, with some modifications, it can also be used to calculate the wavelengths of light emitted by atoms of other elements. Hence, the initial energy level is n = 3

Rydberg equation:

1/λ = f/c = R(1/m² - 1/n²)

where c is the speed of light, f is frequency, λ is the wavelength, R is Rydberg constant, and n and m are the quantum numbers of the energy levels.

The initial energy level has quantum number n.

The final energy level is a ground state with the quantum number m = 1.

2.924 x 1015/2.998 x 108 = 1.097 x 107 x (1/12 - 1/n²)

(1/12 - 1/n²) = 0.8891

1/n² = 0.1109

=> n²

= 9

=> n = 3

Thus, the initial energy level is n = 3

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The electron in the hydrogen atom was in the 9th energy level (n = 9) before emitting the photon.

When a hydrogen atom transitions from an excited state to the ground state, it emits a photon with a certain frequency. In this case, the frequency is given as ν = 3.084 x 10^15 s^-1. We can use the equation ν = E/h, where E is the energy of the photon and h is Planck's constant, to find the energy of the emitted photon. Once we have the energy, we can determine the energy level the electron was in before the photon was emitted.

Using the energy-frequency relationship and Planck's constant, we have:

E = hν = (6.626 x 10^-34 J s)(3.084 x 10^15 s^-1) ≈ 2.041 x 10^-18 J

From this energy, we need to find the corresponding energy level. The energy levels of hydrogen are given by the formula: E = -13.6 eV/n^2, where E is the energy of the level and n is the principal quantum number. Rearranging the formula, we have:

n^2 = -13.6 eV/E ≈ -13.6 eV/(2.041 x 10^-18 J) ≈ -6.662 x 10^17

Taking the square root of both sides, we find:

n ≈ -8.159 x 10^8

Since n must be a positive integer, we can conclude that the electron was in the 9th level (n = 9) before emitting the photon.

Answer:b

Explanation:

Answer: B. Compressing 2 liters of water into a 1 liter volume.

Explanation: Liquids have little compressibility as compared to gases. Their molecules are quite near each other compared to gases which far apart. When liquids are compressed up to their capacity it will begin to resist. But gases have higher compressibility rate than liquids.

Answer:

Never leave an open flame unattended

Explanation: if an open flame is left unattended it can cause a fire outbreak so we have to watch it at all times to prevent the fire outbreak

Answer:

False.

Explanation:

The given statement is false because for hot vacuum filtration, the filter paper should be wet rather than dry when pouring the hot solution into the Buchner funnel. This is because The possible explanation the filter paper needs to be wetted is not only to allow it to adhere to the funnel, but also to promote the solute to filter down readily across its pores of the paper without wetting it (this is true for organic and aqueous solvents).

To calculate the molar concentration of HNO3 in the solution, use the balanced chemical equation to determine the mole ratio and then calculate the moles of HNO3 used. Finally, divide the moles of HNO3 by the volume of the solution to get its molar concentration.

To calculate the molar concentration of HNO3, we first need to use the balanced chemical equation to determine the mole ratio between HNO3 and LiOH. The balanced equation is 2HNO3 + 2LiOH → 2LiNO3 + H2O. From the equation, we can see that 2 moles of HNO3 react with 2 moles of LiOH. Since we know the molar concentration of LiOH and the volume used, we can calculate the moles of LiOH used: (12.5 mL)(1.0x10^-4 M) = 0.00125 moles of LiOH. Since the mole ratio is 1:2, the moles of HNO3 used would be half of that, which is 0.000625 moles of HNO3. Now, we can use the volume of the HNO3 solution to calculate its molar concentration:

Molar concentration of HNO3 = (0.000625 moles) / (25.0 mL) = 0.025 M HNO3

Final answer:

The molar concentration of HNO3 is 5.00x10-5 M.

Explanation:

To calculate the molar concentration of HNO3, we first need to determine the number of moles of LiOH used in the titration. The molarity of the LiOH solution is given as 1.0x10-4 M, and the volume used is 12.5 mL (0.0125 L).

moles of LiOH = Molarity x Volume = (1.0x10-4 M) x (0.0125 L) = 1.25x10-6 mol

Since the balanced chemical equation shows a 1:1 ratio between LiOH and HNO3, the number of moles of HNO3 is also 1.25x10-6 mol.

To find the molar concentration of HNO3, we use the volume of the HNO3 solution, which is 25.0 mL (0.025 L).

Molarity of HNO3 = moles of HNO3 / Volume = (1.25x10-6 mol) / (0.025 L) = 5.00x10-5 M HNO3

Answer:

The answer to your question is 1.46 moles of KMnO₄

Explanation:

Data

number of moles = ?

mass = 230.8 g

molecular mass of KMnO₄ = 39 + 55 + (16 x 4) = 158 g

Process

1.- Use proportions and cross multiplication to answer this problem.

                          158 g of KMnO₄ ----------------  1 mol

                           230.8 g of KMnO₄ -----------    x

                           x = (230.8 x 1) / 158

2.- Simplifying

                           x = 230.8 / 158

3.- Result

                          x = 1.46 moles

Answer:

FALSE                            

Explanation:

The incident of Muese Valley occured in 1930 due to air pollution.

Muese Valley lies along the river Muese which is situated Huy and Liege, Belgium. This region was crowded with industries including steel manufacturers, glass manufacturers, explosives plants, zinc smelter, etc.

The increase number of industries and population lead to the sources of pollution. Also increase in burning of domestic coal increased pollution surrounding the area.

Air pollution became so severe at this region that people have severe  respiratory problems. Residents suffered from vomiting, retrosternal pain, coughing fits and several experienced nausea. There were fog and smog all over and many people died.

Hence the answer is FALSE.

A barium fluoride solution with a concentration of 1.32 grams per liter, equivalent to its solubility, would be considered saturated. This means that no more barium fluoride can be dissolved in the water at the same temperature.

The solubility of barium fluoride in water is 1.32 grams per liter. Therefore, if a barium fluoride solution had a concentration of 1.32 grams per liter, it would be referred to as being saturated. A saturated solution is a solution in which no more solute can be dissolved in the solvent at a given temperature. In this case, the maximum amount of barium fluoride that can be dissolved in water at the given temperature has been reached.

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Answer:

The answer to your question is below

Explanation:

Propane is a hydrocarbon that has only single bonds in its structure so it is an alkane.

Propane formula = C₃H₈

Oxygen formula = O₂

Carbon dioxide formula = CO₂

Water formula = H₂O

Reaction:

                         C₃H₈  +   5O₂   ⇒    3CO₂   +   4H₂O

                  Reactants            Elements     Products

                          3                          C                    3

                          8                          H                    8

                         10                         O                   10

Answer:

0.3758moles

Explanation:

moles of kcl = mass of kcl/ molar mass of kcl = 28/74.5 = 0.3758moles

Answer:

We have 0.376 moles in 28.0 grams of KCl

Option C is correct.

Explanation:

Step 1: Data given

Mass KCl = 28.00 grams

Molar mass KCl = 74.55 g/mol

Step 2: Calculate moles KCl

Moles KCl = mass KCl / moalr mass KCl

Moles KCl = 28.0 grams / 74.55 g/mol

Moles KCl = 0.376 moles KCl

We have 0.376 moles in 28.0 grams of KCl

Option C is correct.

To find the heat of combustion for cyclopropane in kcal/gram, divide the heat of reaction (499.8 kcal/mol) by the molar mass of cyclopropane (42.08 g/mol).

The heat of combustion for cyclopropane in kcal/gram can be calculated using its molar mass and the given heat of reaction. The molar mass of cyclopropane, C3H6, is 42.08 g/mol. With a heat of reaction of 499.8 kcal/mol, we can calculate the heat of combustion per gram by dividing the heat of reaction by the molar mass:

Heat of combustion (kcal/g) = Heat of reaction (kcal/mol) / Molar mass (g/mol)

Thus,

Heat of combustion (kcal/g) = 499.8 kcal/mol / 42.08 g/mol

Once you perform the division, you'll have the heat of combustion for cyclopropane in kcal/gram.

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Final answer:

To balance the equation C₂H₆ + O₂ → CO₂ + H₂O, we end up with a balanced chemical equation of 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O, where the coefficient of O₂ is 7.

Explanation:

The question concerns the balancing of a chemical equation involving ethane (C₂H₆) and oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O). Balancing chemical equations requires ensuring that the number of atoms of each element is the same on both sides of the equation. Starting with the unbalanced equation C₂H₆ + O₂ → CO₂ + H₂O, we first balance the carbons (C) and hydrogens (H) by adjusting the coefficients of the products. For example, the equation can be balanced by placing a coefficient of 3 before H₂O and 2 before CO₂, resulting in C₂H₆ + O₂ → 2CO₂ + 3H₂O. However, this leads to seven oxygen atoms on the product side. We need an even number of oxygen atoms to balance them with the O₂ reactant, so we use a fractional coefficient of 3.5 (which is 7/2) in front of O₂.

To remove the fractional coefficient, we can multiply all coefficients by 2, resulting in the balanced chemical equation: . Thus, the coefficient of O₂ when the equation is balanced is 7.

Answer:

The answer to your question is the original dose of Ba-142 was 1184 μg

Explanation:

Data

Total time = 1.25 hours

The Final amount of Ba = 9.25 μg

The Half-life of Ba = 10.6 minutes

Process

1.- Convert total time to minutes

                      1 h ----------------- 60 min

                       1.25 h ------------ x

                        x = 75 min

2.- Draw a table of this process

                   Final amount of Ba               Time

                           9.25                                 75 min

                           18.5                                  64.4 min

                           37                                     53.8 min

                           74                                     43.2 min

                          148                                     32.6 min

                          296                                    22  min

                          592                                    11.4 min

                         1184                                      0.8 min