how to find the group number of f block elements​

Answer:

3.1621 × 10²⁵ molecules

Explanation:

From the given information:

Moles of C2H8 = 52.5 moles

number of moles = mass/molar mass

molar mass of C2H8 = (6 *2) + (1*8)

= 12 + 8

= 20 g/mol

∴

52.5 moles = mass of C2H8 / 20 g/mol

mass of C2H8 = 52.5 moles × 20 g/mol

mass of C2H8 = 1050 grams

Recall that;

1 mole = 6.023 × 10²³ molecules

∴ 52.5 moles of C2H8 = (52.5 × 6.023 × 10²³) molecules

=3.1621 × 10²⁵ molecules

Answer:

Explanation:

The pH of a solution can be found by using the formula

[tex]pH = - log [ { H_3O}^{+}][/tex]

From the question we have

[tex]ph = - log(5.2 \times {10}^{ - 8} ) \\ = 7.28399[/tex]

We have the final answer as

Hope this helps you

Answer:

A) the mass in grams of one mole of a substance.

Explanation:

The molar mass of a substance is the mass in grams of 1 mole of the substance. As shown in this video, we can obtain a substance's molar mass by summing the molar masses of its component atoms. We can then use the calculated molar mass to convert between mass and number of moles of the substance.

The amount of energy needed to freeze 12.5 grams of water into ice is equals to 14.295 kilo joules.

Energy required to freeze water will be calculated by using the following equation as:

Q = mcT, where

m = mass of water = 12.5g = 0.0125kg

c = specific heat of water = 4.187 kJ/kg.K

T = temperature to freeze = 0 degree C = 273.15 K

On putting values we get,

Q = (0.0125)(4.187)(273.15)

Q = 14.295 kJ

Hence required amount of energy is 14.295 kJ.

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Answer:

The total pressure is 61.4 kPa, and the volume is 1.31 L.

Explanation:

Based on the given information, a gas mixture comprising 320 mg or 0.320 grams of CH4, 175 mg or 0.175 grams of Ar, and 225 or 0.225 grams of N. The number of moles of the gases presents within the mixture can be determined by using the formula,

Number of moles = Mass/ molecular mass

The molecular mass of methane is 16.04 grams per mole, the molecular mass of Argon is 40 grams per mole, and the molecular mass of Nitrogen is 28.02 grams per mole.

Now, the number of moles of CH4 is,

= 0.320 grams/ 16.04 grams per mole

= 0.0199 moles

The number of moles of Ar is,

= 0.175 grams/40 grams per mole

= 0.0044 moles

The number of moles of N2 is,

= 0.225 grams/28.02 grams per mole

= 0.0080 moles

The partial pressure of nitrogen given is 15.2 kPa or 0.15 atm. Thus, the partial pressure of other two gases will be,

CH4 = (15.2 kPa) (0.0199 moles)/(0.0080 moles)

= 37.8 kPa

Ar = (15.2 kPa) (0.0044 moles)/(0.0080 moles)

= 8.36 kPa

Therefore, the total pressure is 15.2 + 37.8 + 8.36 = 61.4 kPa or 0.606 atm

The total volume can be determined by using the formula,

V = nRT/P

Here n is the total number of moles of the gas, which is 0.0323 moles.

Now putting the values we get,

V = (0.0323 moles) (0.0826 atm*L/mol*K)(300 K)/(0.606 atm)

V = 1.31 L

Answer:

See explanation

Explanation:

We must remember that the energy required to move an electron from the 1s orbital to a higher energy level depends on the size of the nuclear charge.

The higher the nuclear charge, the more closely held the 1s electron of the atom is to the nucleus and the more difficult it is to excite this electron.

Hence, it requires more energy to excite the 1s electron of silver having a larger size of nuclear charge than it is to excite a 1s electron in lithium.

Answer:

[tex]heat = mc \triangle \theta \\ = 70 \times 4.18 \times (87 - 21) \\ = 19311.6 \: joules[/tex]

Answer: The value of [tex]K_{c}[/tex] for this reaction is 250000.

Explanation:

The given equation is as follows.

[tex]2NH_{3}(g) + 3I_{2}(g) \rightleftharpoons N_{2}(g) + 6HI(g)[/tex]

[tex]N_{2}(g) + 3H_{2}(g) \rightleftharpoons 2NH_{3}(g); K_{c_{1}} = 0.50[/tex]   ... (1)

[tex]H_{2}(g) + I_{2}(g) \rightleftharpoons 2HI(g); K_{c_{2}} = 50[/tex]  ... (2)

To balance the atoms, multiply equation (2) by 3. Hence, the equation (2) can be re-written as follows.

[tex]3H_{2}(g) + 3I_{2}(g) \rightleftharpoons 6HI(g); K_{c_{2}} = (50)^{3}[/tex]  ... (3)

Now, subtract equation (1) from equation (3). So, the equation formed will be as follows.

[tex]3I_{2} - N_{2} \rightleftharpoons 6HI - 2NH_{3}[/tex]

This equation can also be re-written as follows.

[tex]3I_{2} + 2NH_{3} \rightleftharpoons N_{2} + 6HI[/tex]

This equation is similar to the equilibrium equation given to us.

Therefore, during this subtraction the equation constants get divided as follows.

[tex]K^{'}_{c} = \frac{K_{c_{2}}}{K_{c_{1}}}\\= \frac{(50)^{3}}{0.50}\\= 250000[/tex]

Thus, we can conclude that the value of [tex]K_{c}[/tex] for this reaction is 250000.

Answer:

gas molecules spread out in response to a concentration gradient.

Explanation:

Diffusion can be defined as the movement of gas molecules from a region of high concentration to a region of lower concentration until an equilibrium is attained or reached. This mixing of gas molecules in the liquid or gaseous state is due to their kinetic energy of random motion i.e without requiring bulk motion.

This ultimately implies that, diffusion is a phenomenon through which gas molecules in either a gaseous or liquid state spread out in response to a concentration gradient, which is simply the difference in concentration of the gases across a space.

In conclusion, increasing the surface area of a gas increases its collision rate and it's considered to be an evolutionary strategy that maximizes the diffusion of gas molecules by catalysing the rate of a gaseous reaction.

Answer:

6.56x10⁻³ mol

Explanation:

First we calculate how many HCl moles are there in 50.0 mL of a 0.1800 M solution:

Then we need to calculate how many HCl moles were in excess, that number is the same as the number of NaOH moles they reacted with:

Finally we calculate the difference between the original number of HCl moles and the number remaining after the reaction with XnCO₃:

Answer:

C4H10

Explanation:

you already written it :)

Answer:

[tex]{ \tt{aromatic \: alkanes}} \\ \\ { \underline{ \blue{ \tt{becker⚜jnr}}}}[/tex]

1. Determine the number of sides of the cyclic compound.

2. Use IUPAC theory, determine the functional group and its position.

Answer:

Explanation:

ANCHOR ANCHOR ANCHOR ANCHOR

Answer: covalent bonds

Explanation:

Answer: See image attached!

Good luck with your future exams!

The value of the solubility of product for CaSO₄ in pure water at 0 °C is 1.1881

The solubility of product (Ksp) is defined as the concentration of products raised to their coefficient coefficients. This is illustrated below:

mA <=> nC + eD

Ksp = [C]^n × [D]^e

With the above information in mind, we can obtain the solubility of the product. This is illustrated below:

CaSO₄(aq) → Ca²⁺(aq) + SO₄²⁻(aq)

From the balanced equation above,

1 mole of CaSO₄ contains 1 mole of Ca²⁺ and 1 mole of SO₄²⁻

From the balanced equation above,

1 mole of CaSO₄ contains 1 mole of Ca²⁺ and 1 mole of SO₄²⁻

Therefore,

1.09 g/L of CaSO₄ will also contain

CaSO₄(aq) → Ca²⁺(aq) + SO₄²⁻(aq)

Ksp = [Ca²⁺] × [SO₄²⁻]

Ksp = 1.09 × 1.09

Ksp = 1.1881

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Answer:

e. the strong base reacts with HA to give A, which is a weak base

Explanation:

Let's consider a buffer made up of a weak acid, HA, and the sodium salt of its conjugate base, NaA. The function is a buffer system is to muffle the change in the pH when an acid or a base is added.

Let's suppose a strong base is added. Then, OH⁻ would be more available. OH⁻ ions react with the acid component of the buffer and its effect is reduced. The corresponding reaction is:

OH⁻ + HA ⇄ A⁻ + H₂O

As we can see, the strong base reacts with HA to give A, which is a weak base.

Complete question is;

The specific heat capacity of a pure substance can be found by dividing the heat needed to change the temperature of a sample of the substance by the mass of the sample and by the change in temperature. The specific heat capacity of a certain substance has been measured to be 3.52 J/g°C. Suppose 420.0 g of the substance is heated until the temperature of the sample has changed by 43.8 °C.

Write an equation that will let you calculate the last Q that was needed for this temperature change. Your equation should contain only symbols. Be sure to define each symbol.

Answer:

Q = m•c•Δt

Q = 64753.92 J

Explanation:

We are given;

Mass (m) = 420 g

Change in temperature; (Δt) = 43.8 °C

Specific heat capacity (c) = 3.52 J/g °C

The last Q is simply the heat energy that caused that temperature change.

This is given by the formula;

Q = m•c•Δt

Plugging in the relevant values;

Q = 420 × 3.52 × 43.8

Q = 64753.92 J

Answer:

See explanation and image attached

Explanation:

When 1 mole of hydrogen is added to 3-hexyne, the addition occurs on the same face or side of the triple bond to yield cis-2-hexene in the presence of lindlar catalyst which prevents further hydrogenation. This is known as syn addition.

The syn addition is achieved because the hydrogen molecule is first adsorbed on the surface of the palladium metal and is subsequently attached to the same face of the triple bond in 3-hexyne as shown in the image attached to this answer.

Answer:

Option A. Substitution

Explanation:

To know which option is correct, let us define each option. This is illustrated below:

A substitution reaction is a reaction in which an halogen replaces hydrogen in a hydrocarbon to produce alkyl halide and the corresponding acid. For example:

RH + X₂ –> RX + HX

NOTE:

R => is an alkyl group

X => is an halogen (F₂, Cl₂, Br₂ or I₂)

Addition reaction is a reaction in which two reactants combined to form a new compound without any loss of the reactants. This reaction is peculiar to only unsaturated hydrocarbon. For example:

CₓHᵧ + A₂ —> ACₓHᵧA

NOTE:

CₓHᵧ => unsaturated hydrocarbon (alkene, alkyne)

A₂ => halogen (F₂, Cl₂, Br₂ or I₂) or HBr, HCl etc

Esterification is a reaction involving carbonxylic and alcohol to produce ester and water. For example:

RCOOH + HOR —> RCOOR + H₂O

NOTE:

R => is an alkyl group

Polymerization is a process of reacting smaller molecules called monomers to form a larger molecule called polymer.

With the information provided above, we can see that the reaction:

CH₄ + Br₂ —> CH₃Br + HBr

Is a substitution reaction since Br replaces H in CH₄ to produce CH₃Br and the corresponding acid i.e HBr

Answer:

[tex]2.17gO_2[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the mass of 4.09 x 10^22 molecules of oxygen gas by firstly keeping in mind that that 1 mole of it has a mass of 32.0 g and secondly that 1 mole of any substance contains 6.022x10^23 representative units, in this case, molecules of O2, and thus, the appropriate setup to perform this conversion is shown below:

[tex]4.09x10^{22}molecules \ O_2*\frac{1molO_2}{6.022x10^{23}molecules \ O_2}*\frac{32.0gO_2}{1molO_2} \\\\2.17gO_2[/tex]

Regards!

Answer:

I think it's 2-methylhept-2-ene

Explanation:

Hope this will help and correct me if I'm wrong.

Answer:

Angle of incidence = angle of reflection = 0

Explanation:

Given that,

A light beam strikes a shiny object at a 90-degree angle.

The angle made by incident ray and normal to the mirror is called the angle of incidence and the angle made by the reflected ray and the normal is called the angle of reflection.

Here, the beam strikes normally. So, the angle of incidence is 0.

A/c to the law of reflection,

Angle of incidence = angle of reflection

So, the angle of reflection is also equal to 0.

Answer:

277.8g of NH4Cl are needed

Explanation:

Based on the reaction, 1mol of NH4Cl reacts producing 1 mole of HCl. To solve this question we must find the moles of HCl using ideal gas law. These moles = Moles NH4Cl:

Moles HCl = Moles NH4Cl

PV = nRT; PV/RT = n

Where P is pressure = 1.22atm,

V is volume = 200L,

R is gas constant = 0.082atmL/molK

And T is absolute temperature = 573K

Replacing:

1.22atm*200L/0.082atmL/molK*573K = n

n = 5.193 moles HCl = Moles NH4Cl

Mass NH4Cl -Molar mass: 53.491g/mol-

5.193 moles * (53.491g / mol) =

Answer:

0.464 L

Explanation:

Molarity (M) = number moles (n) ÷ volume (V)

According to the information given in this question:

number of moles (n) = 4.36 moles

Molarity = 9.4M

Volume = ?

Using M = n/V

9.4 = 4.36/V

9.4V = 4.36

V = 4.36/9.4

V = 0.464 L

Hence, 0.464L of water are needed the volume of water.

Hi there! Answer is below :)

Explanation:

For this question, we apply Boyle's Law and Charles' Law.

When you double the amount of pressure and temperature of a compound or mixture, the volume will decrease by a half. So, if the pressure and temperature are 2, and the volume is 1, and you double, your volume will be 0.5 and your pressure and temperature will be 4.

Best of Luck!

Answer: Its A nucleic acids

Explanation:

Nucleic acids, and DNA in particular, are key macromolecules for the continuity of life. DNA bears the hereditary information that's passed on from parents to children, providing instructions for how (and when) to make the many proteins needed to build and maintain functioning cells, tissues, and organisms.

Nucleic acids carry genetic information from parents to their children.

Nucleic acids are biopolymers, macromolecules, essential to all known forms of life.[1] They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If the sugar is ribose, the polymer is RNA; if the sugar is the ribose derivative deoxyribose, the polymer is DNA.

Nucleic acids are naturally occurring chemical compounds that serve as the primary information-carrying molecules in cells and make up the genetic material. Nucleic acids are found in abundance in all living things, where they create, encode, and then store information of every living cell of every life-form on Earth. In turn, they function to transmit and express that information inside and outside the cell nucleus to the interior operations of the cell and ultimately to the next generation of each living organism. The encoded information is contained and conveyed via the nucleic acid sequence, which provides the 'ladder-step' ordering of nucleotides within the molecules of RNA and DNA. They play an especially important role in directing protein synthesis.

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Answer:

Explanation:

The reaction is 2H2 + O2 -> 2 H2O

So the molar ratio of H2 and O2 is 2:1

No. of moles of H2 = 12.5/2 = 6.25

No. of moles of O2 = 5.14/32 =0.16

As 6.25 > 0.16*2 = 0.32

there will be H2 leftovers of 6.25-0.32 = 5.93 moles or 11.86 grams

Answer:

Explanation:

2 H2 + 1 O2 => 2 H2O

molecular wt of H2 = 2

molecular wt of O2 = 32

so wt of H2 : wt of O2 = 2x2 : 16 = 4 : 16 = 1 : 4

there are way more H2 as 12.5 > 5.14/4 = 1.285

H2 leftovers = 12.5 - 1.285 = 11.215 gram

Answer:

HCl(aq) + KOH(aq)---------->KCl (aq)+ H2O(l)