what is the purpose of washing the precipitate with hot water in step 3(a) of the procedure? be as specific as possible in your answer

Answer:

moles Pb(NO₃)₂ ≅ 0.0213 mole (three sig. figs.)

Explanation:

converting...

grams to moles => divide by formula weight

moles to grams => multiply by formula weight

for this problem ...

moles Pb(NO₃)₂ = 7.04g / 331.2g/mol = 0.021256 (calculator answer)

≅ 0.0213 mole (three sig. figs.)

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore,  the number of moles in 7.04 g of lead (II) nitrate, Pb(NO₃)₂ is 0.0212moles.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

mole =given mass ÷ molar mass

Molar mass of 1 mole of  Pb(NO₃)₂ = 331.2g/mol

given mass of Pb(NO₃)₂=7.04g

Substituting the values in above formula we get

moles of Pb(NO₃)₂ = 7.04g / 331.2g/mol

moles of Pb(NO₃)₂ = 0.0212moles

Therefore,  the number of moles in 7.04 g of lead (II) nitrate, Pb(NO₃)₂ is  0.0212moles.

To know more about mole, here:

https://brainly.com/question/15209553

#SPJ2

For the B₁-B₂ cell pair, B₂ is the cathode, and B₁ is the anode. For the A₁-B₂ cell pair, B₂ is the cathode, and A₁ is the anode. For the A₂-B₂ cell pair, B₂ is the cathode, and A₂ is the anode.

B₁-B₂:

The half-reaction at B₁ is given as A⁺(aq) + 2e⁻ → A(s) with a reduction potential of -0.78 V.

The half-reaction at B₂ is given as B⁺(aq) + e⁻ → B(s) with a reduction potential of -0.45 V.

Since the reduction potential of B₂ (-0.45 V) is more positive than B₁ (-0.78 V), B2 will be the cathode, and B1 will be the anode.

A₁-B₂:

The half-reaction at A₁ is given as C⁺(aq) + 2e⁻ → C(s) with a reduction potential of -0.95 V.

The half-reaction at B₂ is the same as mentioned before B⁺(aq) + e⁻ → B(s) with a reduction potential of -0.45 V.

Since the reduction potential of B₂ (-0.45 V) is more positive than A₁ (-0.95 V), B₂ will be the cathode, and A₁ will be the anode.

A₂-B₂:

The half-reaction at A₂ is given as D⁺(aq) + 2e⁻ → D(s) with a reduction potential of -0.70 V.

The half-reaction at B₂ is the same as mentioned before B⁺(aq) + e⁻ → B(s) with a reduction potential of -0.45 V.

Since the reduction potential of B₂ (-0.45 V) is more positive than A₂ (-0.70 V), B₂ will be the cathode, and A₂ will be the anode.

Learn more about electrode potential here:

https://brainly.com/question/31872210

#SPJ4

You can take physics as a hobby and also it is great that you like both maths and physics as well and also want to be an computer science engineer because physics and math

Answer:

The answer is

2 moles of hydrogen react with 1 mole of oxygen to form 2 moles of water

To find the half-life of sodium-24, we can use the formula for exponential decay:

N(t) = N₀ * (1/2)^(t / t₁/₂)

Where:

N(t) is the amount of the substance remaining at time t

N₀ is the initial amount of the substance

t is the time elapsed

t₁/₂ is the half-life of the substance

Given:

N₀ = 6.00 mg (initial amount)

N(t) = 0.750 mg (amount after 45 hours)

Plugging in these values, we can solve for t₁/₂:

0.750 mg = 6.00 mg * (1/2)^(45 / t₁/₂)

Dividing both sides of the equation by 6.00 mg:

(0.750 mg) / (6.00 mg) = (1/2)^(45 / t₁/₂)

0.125 = (1/2)^(45 / t₁/₂)

To eliminate the base of 1/2, we can take the logarithm of both sides:

log₂(0.125) = 45 / t₁/₂ * log₂(1/2)

Using the property log₂(a^b) = b * log₂(a):

log₂(0.125) = 45 * log₂(1/2) / t₁/₂

We know that log₂(1/2) = -1, so we can simplify the equation further:

log₂(0.125) = -45 / t₁/₂

Now, we can solve for t₁/₂:

t₁/₂ = -45 / log₂(0.125)

Using a calculator:

t₁/₂ ≈ -45 / (-3) ≈ 15

The half-life of sodium-24 is approximately 15 hours.

Learn more about decay here : brainly.com/question/32086007
#SPJ11

Answer:

Light waves are electromagnetic waves while sound waves are mechanical waves. light waves are transverse while sound waves are longitudinal. sound waves require a material medium to travel, and hence, cannot travel in a vacuum. the speed of light in a medium is constant.

Explanation:

Hope this helped Mark BRAINLIEST!!

The most appropriate explanation among the given options for the fact that the ion-solvent interaction is greater for Li⁺ than for K⁺ is that "Li⁺ has a smaller ionic radius than K⁺." Option D is correct.

Ionic radius refers to the size of an ion, specifically the distance between the nucleus and the outermost electron shell. Smaller ions tend to have stronger interactions with solvent molecules because the charge is more concentrated in a smaller space, leading to a higher electrostatic attraction between the ion and the surrounding solvent molecules.

In this case, Li⁺ has a smaller ionic radius compared to K⁺. As a result, Li⁺ has a stronger interaction with the solvent molecules, which leads to a greater ion-solvent interaction.

Hence, D. is the correct option.

To know more about ion-solvent interaction here

https://brainly.com/question/14135431

#SPJ4

--The given question is incomplete, the complete question is

"Which of the following explanations accounts for the fact that the ion-solvent interaction is greater for Li⁺ than for K⁺? A) The ionization energy of Li is higher than that for K. B) Li has a lower density than K. C) Li⁺ is of a lower mass than K⁺ D) Li⁺ has a smaller ionic radius than K⁺ E) Li reacts with water more slowly than K."--

Answer:  Shaun must consume 6 more g of protein to reach the required amount.

Explanation:

Given : Recommended amount of protein = 200 calories

Now 4 calories = 1 gram of protein

Thus 200 calories = [tex]\frac{1}{4}\times 200=50[/tex] g of protein.

Calories consumed per day by Shaun = 176 calories

176 calories =  [tex]\frac{1}{4}\times 176=44[/tex] g of protein.

Thus Shaun need to consume = (50-44) g = 6 of protein to reach the required amount.

Shaun must consume 6 more g of protein to reach the required amount.

CBr₄ has a higher vapor pressure at the same temperature than CCl₄. The statement is False.

The vapor pressure of a liquid is the pressure exerted by the vapor of the liquid in equilibrium with the liquid. The vapor pressure of a liquid depends on the strength of the intermolecular forces in the liquid. The stronger the intermolecular forces, the lower the vapor pressure.

In the case of CCl₄ and CBr₄, the intermolecular forces are London dispersion forces. The size of the atom or molecule affects the strength of the London dispersion forces. The larger the atom or molecule, the stronger the London dispersion forces.

Bromine is larger than chlorine, so the intermolecular forces in CBr₄ are stronger than the intermolecular forces in CCl₄. Therefore, CCl₄ will have a higher vapor pressure than CBr₄ at the same temperature.

To know more about vapor pressure, refer here:

https://brainly.com/question/29640321#

#SPJ11

Answer:

True

Explanation:

Answer:

B. An equation that shows only those particles involved in the reaction, and that is balanced for both mass and charge

Explanation:

A net ionic equation is a chemical equation that will only show the elements, compounds, and ions that are directly involved in the chemical reaction. It comes from the balanced molecular equation and should be balanced by both mass and charge.

The mass of the ice melted by a complete transfer of thermal energy is 83.84 g.

The mass of the ice melted by a complete transfer of thermal energy is calculated by applying the following equation as follows;

Q = mcΔθ

where;

heat gained by the ice = heat loss by the steam

The mass of the ice melted by a complete transfer of thermal energy is calculated;

m x heat of fusion = 12.39g x heat of vaporization

m x 334 J/g = 12.39 g  x 2260 J/g

334m = 28,001.4

m = 28,001.4 / 334

m = 83.84 g

Learn more about heat capacity here: https://brainly.com/question/16559442

#SPJ4

The pressure equilibrium constant expression for the given reaction 2Li3N(s) ⇌ 6Li(s) + N2(g) is given below: P = (PN2 ) (PLi)6/ (PLi3N )2Where, PN2 is the partial pressure of nitrogen PLi is the partial pressure of lithiumPLi3N is the partial pressure of lithium nitride.

The above formula of pressure equilibrium constant expression gives the ratio of the product of partial pressures of reactants and products to the power of their stoichiometric coefficients. Here, the stoichiometric coefficients of Li3N, Li and N2 are 2, 6 and 1 respectively. The reaction 2Li3N(s) ⇌ 6Li(s) + N2(g) represents the dissociation of lithium nitride to lithium and nitrogen gases. The dissociation reaction is endothermic.

As the temperature increases, the dissociation of lithium nitride increases which results in the formation of more lithium and nitrogen gas molecules. Therefore, the value of the equilibrium constant for this reaction increases with increasing temperature. The above-pressure equilibrium constant expression helps to determine the equilibrium concentration of reactants and products when the reaction is in equilibrium.

know more about pressure equilibrium,

https://brainly.com/question/32260359

#SPJ11

Answer:

When we stand on the floor, we apply a force on the floor surface in the downward direction and in return the floor also exerts an upward and equal force on us.

Explanation:

Newton' third law is vey famous and it states that for each and every action, there applies an equal but opposite reaction. Thus the action force and the reaction force always acts on pairs. But they does not contribute to the motion of the object.

One such example that illustrates the action and reaction force from Newton's law is when we stand on the floor we exert a force on the floor surface in downward direction. The floor surface also exerts an opposite and equal force on us in the upward direction.

Answer:

C: Warm water is denser than cold water

Answer:

10.4 hours

Explanation:

Now from;

0.693/t1/2 = 2.303/t log (No/N)

t1/2= half life of the radioactive isotope

t = age of the radioactive isotope

No= Original amount of radioactive isotope

N= amount of radioactive isotope left after time t

Substituting values;

N = 0.0625No

0.693/2.6 = 2.303/t log (No/0.0625No)

0.693/2.6 = 2.303/t log (1/0.0625)

0.267 = 2.303/t * log 16

0.267 = 2.773/t

t = 2.773/0.267

t = 10.4 hours

At a pressure of 537.7 torr, pure water would boil at approximately 95.8°C.

To calculate the boiling point of water at a given pressure, we can use the Clausius-Clapeyron equation:

ln(P2/P1) = (-ΔHvap/R) × (1/T2 - 1/T1)

where:

P1 and P2 are the initial and final pressures,

ΔHvap is the molar enthalpy of vaporization,

R is the ideal gas constant (8.314 J/(mol·K)),

T1 is the initial temperature,

T2 is the final temperature.

In this case, we want to find the boiling point (T2) of water at a pressure of 537.7 torr. The normal boiling point of water is 100°C (373.15 K) at atmospheric pressure (760 torr).

We can rearrange the equation to solve for T2:

T2 = (1/(((-ΔHvap/R) × (1/T1)) + (ln(P2/P1))))

Substituting the given values:

P1 = 760 torr

P2 = 537.7 torr

ΔHvap = 40.7 kJ/mol (convert to J/mol by multiplying by 1000)

R = 8.314 J/(mol·K)

T1 = 373.15 K

T2 = (1/(((-40.7 kJ/mol × 1000 J/kJ) / (8.314 J/(mol·K)) × (1/373.15 K)) + (ln(537.7 torr/760 torr))))

Calculating this expression gives us:

T2 ≈ 95.8°C

Therefore, at a pressure of 537.7 torr, pure water would boil at approximately 95.8°C.

Learn more about Clausius-Clapeyron equation from the link given below.

https://brainly.com/question/29409537

#SPJ4

Answer:

producer to decomposer

Explanation:

This is because in a food chain , energy flow from one trophic level to another. The producer which include plants are the source of energy which they manufacture good in the presence of light energy from sun. Energy flow directly from the producer to the primary consumer which are heterotrophs that feed on plants. Energy flow from consumer to decomposer after the consumer died and it is decayed.

Answer:

11g/cm^3

Explanation:

The density of a substance can be found By

density= Mass/volume

From the question

mass = 22 g

volume = 2 cm³

22/2=11

We have the final answer as

11 g/cm³

Answer:

11g/cm^3

Explanation:

It is because the constant formula density is

Density=Mass/ Volume.

Therefore we have

Density=22g/2cm^3

Which is = 11g/cm^3

The transition wavelength, λ is given as:λ = (hc)/Eλ = (6.626 x 10^-34 Js * 3 x 10^8 m/s)/(4.585 x 10^-20 J)λ = 4.325 x 10^-7 mλ = 432.5 nmTherefore, if the length of the box is doubled, the transition wavelength remains the same as 200 nm.

The length of the box, L = 1 nm.The transition wavelength, λ = 200 nm.Formula:For particle in a one-dimensional box,For the energy of a particle in a one-dimensional box,E = (n²h²)/(8mL²)where, n = quantum numberh = Planck's constanm = mass of the particleL = length of the box.1. For the lowest energy level,n = 1E₁ = (n²h²)/(8mL²)E₁ = (1²h²)/(8mL²)E₁ = (1*6.626 x 10^-34 Js)²/(8(9.11 x 10^-31 kg)(1 x 10^-9 m)²)E₁ = 9.170 x 10^-20 JFrom the above formula, the probability of finding the particle within 0.01 nm of the center of the box is given as:ψ(x) = sqrt(2/L)sin(nπx/L)Probability, P = ∫ψ²dxFrom the above formula, the probability of finding the particle within 0.01 nm of the center of the box for the lowest-energy level is given as:P = ∫[sqrt(2/L)sin(πx/L)]²dxP = ∫2/L sin²(πx/L)dxP = 2/L * L/2P = 1Hence, the probability of finding the particle within 0.01 nm of the center of the box for the lowest-energy level is 1.2. For the first excited state,n = 2E₂ = (n²h²)/(8mL²)E₂ = (2²h²)/(8mL²)E₂ = (4*6.626 x 10^-34 Js)²/(8(9.11 x 10^-31 kg)(1 x 10^-9 m)²)E₂ = 3.668 x 10^-19 JFrom the above formula, the probability of finding the particle within 0.01 nm of the center of the box for the first excited state is given as:P = ∫[sqrt(2/L)sin(2πx/L)]²dxP = ∫2/L sin²(2πx/L)dxP = 2/L * L/2P = 0.5Hence, the probability of finding the particle within 0.01 nm of the center of the box for the first excited state is 0.5.3. (i) If the mass of the particle is doubled:For the energy of a particle in a one-dimensional box,E = (n²h²)/(8mL²)The energy of a particle is inversely proportional to the mass of the particle.Hence, if the mass of the particle is doubled, the energy of the particle is halved.E = 0.5E₁ = 0.5(9.170 x 10^-20 J)E = 4.585 x 10^-20 JFrom the above formula, the transition wavelength, λ is given as:λ = (hc)/Eλ = (6.626 x 10^-34 Js * 3 x 10^8 m/s)/(4.585 x 10^-20 J)λ = 4.325 x 10^-7 mλ = 432.5 nm(ii) If the charge of the particle is doubled:The charge of the particle does not have any effect on the energy of the particle.Therefore, the transition wavelength, λ remains the same as 200 nm.(iii) If the length of the box is doubled:For the energy of a particle in a one-dimensional box,E = (n²h²)/(8mL²)The energy of a particle is inversely proportional to the length of the box.Hence, if the length of the box is doubled, the energy of the particle is halved.E = 0.5E₁ = 0.5(9.170 x 10^-20 J)E = 4.585 x 10^-20 JFrom the above formula, the transition wavelength, λ is given as:λ = (hc)/Eλ = (6.626 x 10^-34 Js * 3 x 10^8 m/s)/(4.585 x 10^-20 J)λ = 4.325 x 10^-7 mλ = 432.5 nmTherefore, if the length of the box is doubled, the transition wavelength remains the same as 200 nm.

Learn more about transition wavelength here:

https://brainly.com/question/31641614

#SPJ11

Answer:

uhm i believe its D hope i helped

Explanation:

Answer:

D. decomposers

Answer:

4. Reactant

5. Left

I hope this helps ❤️❤️

Answer:

VOLTIC CELL

Battery

Electrical to chemical

Endothermic

Electrolysis

Chemical to electrical

Anode

Anode to cathode

Battery

Endothermic

Negative

Enthomeric

Reduction

Oxidation

ELECTRYOTIC CELL

No

Non spontaneous

positive

negative

yes

Anode

Electrical to chemical

Anode to cathode

Exothermic

positive

oxidation

Electroplating

Chemical to electrical

Hydrogen peroxide and water both contain the same two elements. The chemical formulas of hydrogen peroxide and water are respectively H2O2 and H2O. The two compounds have distinct physical and chemical properties. Here is a long answer to the question posed.

Water is a colorless, odorless, and tasteless liquid that is vital for life. Its melting point is 0 degrees Celsius, while its boiling point is 100 degrees Celsius. Water is the most prevalent chemical substance on Earth, with about 71% of the planet's surface covered by it.

Hydrogen peroxide is a pale blue liquid that is slightly more viscous than water. It has a bitter taste, and its odor is similar to that of bleach. The boiling point of hydrogen peroxide is 150.2°C, while the melting point is -0.43°C. Hydrogen peroxide is a powerful oxidizer that is commonly used as a bleaching agent, disinfectant, and antiseptic.


Chemical formulas are utilized in a variety of scientific applications, including chemical reactions and product descriptions. An incorrect chemical formula can have significant ramifications, potentially resulting in the formation of a hazardous substance.

To know more about Hydrogen peroxide visit:-

https://brainly.com/question/29102186

#SPJ11

Answer:

A

Explanation:

The final concentration of the solution is determined as 0.59 M.

The concentration of a solution or molarity of a solution is defined as the ratio of number of moles of solute to the liters of the solution.

Molarity, M = n / V

where;

The final concentration of the solution is calculated as follows;

the number of moles = 0.5 m

the total volume after adding 500 ml of water = 340 ml + 500 ml = 840 ml = 0.84 L

Molarity = 0.5 m / 0.84 L

Molarity = 0.59 M

Thus, the final concentration of the solution is determined as 0.59 M.

Learn more about concentration here: https://brainly.com/question/26255204

#SPJ4