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Answer:

The concentrations of hydronium and hydroxide ions in a solution with pH 2.6 are 2.51*10⁻³ and 3.98*10⁻¹² respectively.

Explanation:

pH is a measure of the acidity or alkalinity of an aqueous solution. The pH indicates the concentration of hydrogen ions present in certain solutions. Mathematically it is defined as the opposite of the base 10 logarithm or the negative logarithm of the activity of hydrogen ions, whose equation is

pH= -log [H⁺]

So, being pH= 2.6 and replacing in the definition of pH:

2.6= -log [H⁺]

[tex][H^{+} ]=10^{-2.6}[/tex]

[H⁺]=2.51*10⁻³

pOH is a measure of the concentration of hydroxide ions (OH⁻). The sum between the pOH and the pH results in 14:

pOH + pH= 14

So, being pH= 2.6:

pOH + 2.6= 14

pOH= 14 - 2.6

pOH= 11.4

The pOH is defined as the negative logarithm of the activity of the hydroxide ions. That is, the concentration of OH⁻ ions:

pOH= - log [OH⁻]

Being pOH= 11.4 and replacing

11.4= -log [OH⁻]

[tex][OH^{-} ]=10^{-11.4}[/tex]

[OH⁻]= 3.98*10⁻¹²

The concentrations of hydronium and hydroxide ions in a solution with pH 2.6 are 2.51*10⁻³ and 3.98*10⁻¹² respectively.

Answer:

a. The student performed the splint test incorrectly. He should of observed a popping sound when the splint was placed in the test tube.

Explanation:

It is given that a student performed an experiment where he dropped a nickel metal in to HCl solution. He observed the reaction and performed a splint test in the test tube that is filled with a gas which is formed while Nickle is dropped into the solution of HCl.

But the experiment that the student performed was incorrect. He must have observed the popping sound when the splint was placed in the test tube.

When the splint was added to the gas splint flared up. The hydrogen gas pops out when exposed to the flame.

[tex]$Ni + HCl(aq) = NiCl + H_2$[/tex]

Thus the correct option is (a).

Answer:

it's atomic number is 5 and total number is 10

The atom has an atomic number of 20 and has a total of 12 p electrons.

The azimuthal quantum number (l) of the 19th electron is 0 and the magnetic quantum number (m) of the 19th electron is 0.

It is an element of group 2

The number of electrons in the neutral atom is equal to the number of protons and is also the atomic number of an atom.

An atom is known to be electrically neutral. This is because the number of electrons in the atom is equal to the number of protons in the neutral atom.

The number of protons in the neutral atom is called the atomic number of the atom.

For an element that has 20 electrons, its electronic configuration is;

1s2 2s2 2p6 3s2 3p6 4s2.

The 19th electron is in the 4s orbital hence both the azimuthal and magnetic quantum numbers are zero.

The element has outermost electron configuration ns2 so it mus belong to group 2 of the periodic table.

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Answer:

Conversion of 1-methyl cyclopentene to 2-methyl cyclopentanol.

Explanation:

When alkenes react with diborane followed by the reaction with hydrogen peroxide and NaOH then the least substituted carbon in the double bond will be substituted.

The formation of 2-methyl cyclopentanol from 1-methyl cyclopentene is shown below:

Answer: The correct option is ALL OF THE ABOVE.

Explanation:

TITRATION is a type of volumetric analysis which is used for determining the concentration of solutions. In this process a specific volume of a solution is placed in a conical flask by means of a pipette and small quantities of a second solution is slowly added from a burette until the end point is reached. This is determined by a means of an indicator which shows a characteristic colour change.

During titration, the following precautions should be followed to avoid errors and maintain standardisation in the experiment.

--> Any air bubble in the burette and pipette must be removed during measurement

--> the burette tap should be tightened to avoid leakage.

--> Remove the funnel from the burette before taking any reading to avoid errors in reading the volume.

--> use the base solution such as Sodium Hydroxide Solution to rinse the burette after washing with soap and tap water:

• to remove any air bubble and fill it's tip

• to remove any residual liquid from the water and soap solution which may interfere with the results of the experiment.

• to check if the burette is in good condition.

Therefore all of the above options to the question are correct.

Answer:

oxidizer

Explanation:

an example of an oxidizers are oxygen and hydrogen peroxide

Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.

Explanation:

The relation between energy and wavelength is as follows.

[tex]E = \frac{hc}{\lambda}\\[/tex]

This means that energy is inversely proportional to wavelength.

As it is given that energy of a hydrogen atom and a helium atom is same.

Let us assume that [tex]E_{hydrogen} = E_{helium} = E'[/tex]. Hence, relation between their wavelengths will be calculated as follows.

[tex]E_{hydrogen} = \frac{hc}{\lambda_{hydrogen}}[/tex]    ... (1)

[tex]E_{helium} = \frac{hc}{\lambda_{helium}}[/tex]         ... (2)

Equating the equations (1) and (2) as follows.

[tex]E_{hydrogen} = E_{helium} = E'\\\frac{hc}{\lambda_{hydrogen}} = \frac{hc}{\lambda_{helium}} = E'\\\lambda_{helium} = \lambda_{hydrogen} = E'[/tex]

Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.

Explanation:

In the formula of [tex]CaCl_2[/tex] we can see that there are 2mol Cl in 1 molecule of CaCl2. So, now we can do some math to find out how many mol of Cl there are in 1.9mol CaCl2!

[tex]1.9molCaCl_2*\frac{2molCl}{1molCaCl_2}[/tex]

So, there are 3.8mol Cl

Explanation:

mass=kilogram (kg)

temperature=kelvin

power=watt

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Answer:

[tex]n=6\ to\ n=3[/tex]

Explanation:

From the question we are told that:

Wavelength [tex]\lambda=274 *10^{-9}m[/tex]

Bohr's constant [tex]R = 1.097 × 10^7 / m (or m−1)[/tex]

Helium atom [tex]z=2[/tex]

Generally the equation for Wavelength is mathematically given by

 [tex]\frac{1}{\lambda}=Rz^2(\frac{1}{nf^2}-\frac{1}{nf^2})[/tex]

 [tex]0.083=(\frac{1}{nf^2}-\frac{1}{nf^2})[/tex]

Therefore

The Range of n fall at

 [tex]n=6\ to\ n=3[/tex]

Answer:

energy is the ability to do work

Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, [tex]CH_{4}[/tex].

Explanation:

Given: Mass of methane = 146.6 g

As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{146.6 g}{16.04 g/mol}\\= 9.14 mol[/tex]

The given reaction equation is as follows.

[tex]C + 2H_{2} \rightarrow CH_{4}[/tex]

This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.

[tex]Moles of H_{2} = \frac{9.14}{2}\\= 4.57 mol[/tex]

Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, [tex]CH_{4}[/tex].

Answer:

The answer is d because the light is energy of wave

The frequency of a light wave can be determined

So, option D is correct one.

What is frequency?

Energy equation,

[tex]E= hv[/tex]

where,

[tex]E[/tex] = Energy of light

[tex]h[/tex]= Planks constant

[tex]v[/tex] = Frequency of wave.

To learn more about frequency,

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Answer:

4.33 L

Explanation:

Assuming ideal behaviour and that all 0.300 moles of gas reacted, we can solve this problem using Avogadro's law, which states that at constant temperature and pressure:

Where in this case:

We input the given data:

And solve for V₂:

Answer:

it might reach to 4g per L

Answer:

In the case of mixtures of ethanol and water, this minimum occurs with 95.6% by mass of ethanol in the mixture. The boiling point of this mixture is 78.2°C, compared with the boiling point of pure ethanol at 78.5°C, and water at 100°C. You might think that this 0.3°C doesn't matter much, but it has huge implications for the separation of ethanol / water mixtures. The next diagram shows the boiling point / composition curve for ethanol / water mixtures. I've also included on the same diagram a vapor composition curve in exactly the same way as we looked at on the previous pages about phase diagrams for ideal mixtures.

Answer:

66.7%

Explanation:

Step 1: Write the balanced equation

CHCl₃ + Cl₂ ⇒ CCl₄ + HCl

Step 2: Calculate the theoretical yield of CCl₄ from 11.9 g of CHCl₃

According to the balanced equation, the mass ratio of CHCl₃ to CCl₄ is 119.38:153.82.

11.9 g CHCl₃ × 153.82 g CCl₄/119.38 g CHCl₃ = 15.3 g CCl₄

Step 3: Calculate the percent yield of CCl₄

Given the experimental yield of CCl₄ is 10.2 g, we can calculate the percent yield using the following expression.

%yield = (exp yield/theo yield) × 100%

%yield = (10.2 g/15.3 g) × 100% = 66.7%

Answer:

8.61 %

Explanation:

The percent of sodium hypochlorite in the bleach sample can be calculated using the following formula:

We input the data given by the problem:

Answer:

Explanation:

/ means divided by

* means multiply

1. formula is

partial pressure = no of moles(gas 1)/ no of moles(total)

0.30 mol CO/0.60 mol CO2 + 0.30 mol CO + 0.10 mol H20 ->

.3/(.6+.3+.1) =

.3/1 =

.3 =

partial pressure of CO

2.

.3 * .8 atm = .24

khanacademy

quizlet

The partial pressure of the CO is 0.24 atm if the total pressure of the mixture was 0.80 atm.

Dalton's Law of partial pressure states that the total pressure exerted by non reacting gaseous mixture at a constant temperature and given volume is equal to the sum of partial pressure of all gases.

Dalton's Law of partial pressure using mole fraction of gas

Partial pressure of carbon monoxide (CO) = Mole fraction of carbon monoxide (CO) × Total pressure

Now, we have to find the first mole fraction of CO

Mole fraction of carbon monoxide (CO) = [tex]\frac{\text{moles of solute}}{\text{total moles of solute}}[/tex]

                                                                  = [tex]\frac{\text{moles of CO}}{\text{moles of CO}_2 + \text{moles of CO} + \text{moles of H}_{2}O}[/tex]

                                                                  = [tex]\frac{0.30}{0.60 + 0.30 + 0.10}[/tex]

                                                                  = [tex]\frac{0.30}{1}[/tex]

                                                                  = 0.3

Now, put the value in above equation, we get that

Partial pressure of carbon monoxide (CO)

= Mole fraction of carbon monoxide (CO) × Total pressure

= 0.3 × 0.8

= 0.24 atm

Thus, the partial pressure of the CO is 0.24 atm is the total pressure of the mixture was 0.80 atm.

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Answer:

Does a reaction occur when aqueous solutions of copper(II) nitrate and calcium chloride are combined?

Explanation:

The given reaction is an example of a chemical double displacement reaction.

The mutual interchange of the ions takes place.

The balanced chemical equation of the reaction is:

[tex]Cu(NO_3)_2(aq)+CaCl_2(aq) -> Ca(NO_3)_2(aq)+CuCl_2(aq)[/tex]

All the products formed are also highly soluble.

So, all the ions are spectator ions.

Hence, all will cancel with each other and ions remain in the net ionic equation and hence, the reaction does not take place.

Answer:

[tex] a = \frac {2A - bh}{h} [/tex]

Explanation:

Given the following mathematical expression;

A = ½(a + b)h

To make a the subject of formula (express a in terms of A, b and h);

First of all, we would cross-multiply;

2A = (a + b)h

Opening the bracket, we have;

2A = ah + bh

Rearranging the mathematical expression, we have;

ah = 2A - bh

[tex] a = \frac {2A - bh}{h} [/tex]

Answer:

The correct answer is - no not adhere to the law of mass conservation.

Explanation:

According to the law of mass conservation in an isolated system, the mass can not be created or destroyed and in a chemical or physical change, the mass of products should be always equal to the mass of reactants.

On the basis of the law the mass of the chemical reaction-

Mass of products = mass of reactants

33 g of methane + 289g of oxygen = 189g of carbon dioxide + 30g of water

322g ≠ 219 g

which means this reaction does not adhere to the law of conservation.

Answer: It is true about the type of reaction that it is a single replacement reaction, and the cations in the two ionic compounds are different.

Explanation:

When one element in a compound is replaced by another element in a chemical reaction then it is called a single replacement reaction.

For example, [tex]K + NaCl \rightarrow KCl + Na[/tex]

Here, potassium metal is replacing the sodium metal in the sodium chloride compound.

As metals become cation by losing an electron in a chemical reaction.

Thus, we can conclude that it is true about the type of reaction that it is a single replacement reaction, and the cations in the two ionic compounds are different.

Answer: Its A

Explanation:

a single replacement reactions, and the ANIONS in the two ionic compounds are different

Answer:

A. an acid

B. a base

C. conjugate base

D. conjugate acid

Explanation:

This question appears incomplete because it is starting with a "or".

However, the available question can still be answered.

An acid (according to "Bronsted-Lowry") is a chemical compound/specie that can donate hydrogen ion(s) in a reaction while a base is the compound/specie that can receive hydrogen ion(s). From this definition, it can be deduced that CH₃COOH (ethanoic acid) is an acid (weak acid) because it can donate an hydrogen ion while CH₃COO⁻ is a base because it can receive a hydrogen ion.

Also, a conjugate acid is the compound formed when an acid has donated a hydrogen ion to a base (i.e it is a base with hydrogen ion attached to it) while a conjugate base is the acid that has lost it's hydrogen ion. Thus, the conjugate acid in the question is CH₃OH while the conjugate base in the question is CH₃O⁻.

A. an acid

B. a base

C. conjugate base

D. conjugate acid

Answer:

"Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries."

Explanation:

Answer:

second law of thermodynamics

Explanation:

According to the second law of thermodynamics, the total entropy of a system and its surroundings always increases for a spontaneous process.

Entropy is defined as the degree of disorderliness of a system. The entropy of a system never remains constant. It either increases or decreases in a process. The total entropy is the sum of the entropy of the system and its surrounding. The total entropy must increase in a spontaneous process.

Thus, the implication of this law is that even, if the entropy of a system decreases, this must be compensated for by increase in entropy of the surroundings in order for the process to be spontaneous.

Answer: The moles of gas present in the cylinder is 0.34 moles.

Explanation:

Given: [tex]P_{1}[/tex] = 2.7 atm,   [tex]V_{1}[/tex] = 3.1 L,     [tex]T_{1}[/tex] = 300 K

[tex]P_{2}[/tex] = ?,      [tex]V_{2}[/tex] = 9.4 L,       [tex]T_{2}[/tex] = 610 K

Formula used to calculate the final temperature is as follows.

[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]

Substitute the values into above formula as follows.

[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\\frac{2.7 atm \times 3.1 L}{300 K} = \frac{P_{2} \times 9.4 L}{610 K}\\P_{2} = \frac{5105.7}{2820} atm\\= 1.81 atm[/tex]

Now, moles present upon heating the cylinder are as follows.

[tex]P_{2}V_{2} = n_{2}RT_{2}\\1.81 atm \times 9.4 L = n_{2} \times 0.0821 L atm/mol K \times 610 K\\n_{2} = \frac{17.014}{50.081} mol\\= 0.34 mol[/tex]

Thus, we can conclude that moles of gas present in the cylinder is 0.34 moles.