What is the molar mass of BaBrz?

Answer:

1) 16 mL of toluene is necessary to recrystallize 3.2 g of compound A

2) 2.4 g of A is the maximum amount that could be recovered.

3) 1.6 g of compound A  can be recovered if you accidentally use twice as much  toluene as was necessary

Explanation:

1)

The volume of the solvent ( toluene) = [tex]\frac{starting \ amount }{solubility \ at \boiling \ point }[/tex]

= [tex]\frac{3.2 \ g}{0.2 \ g/mL}[/tex]

= 16 mL

∴  16 mL of toluene is necessary to recrystallize 3.2 g of compound A

2)

The maximum amount    A that could be recovered if the saturated solution was allowed to cool to 0 ºC is determined by the difference of the starting amount and amount left in the solution at 0 ºC

i.e

maximum amount of A = 3.2 - ( 16 mL × 0.05 g/mL)

= 3.2 g - 0.8 g

= 2.4 g

∴  2.4 g of A is the maximum amount that could be recovered.

3)

Amount of A that would be  recovered, if you accidentally used twice as much toluene as was necessary is calculated as follows;

amount of A = 3.2g - (32 mL × 0.05 g/mL)

= 3.2 g - 1.6 g

= 1.6 g

Thus; 1.6 g of compound A  can be recovered if you accidentally use twice as much  toluene as was necessary

Metals are good conductors of electricity due to the mobile valence electrons which can move freely within the metallic crystal lattice, facilitating electric charge transfer.

Metals are good conductors of electricity because they contain mobile valence electrons. In metallic bonds, these valence electrons are not associated with a particular atom or pair of atoms, but move freely within the crystal lattice of positively charged metal ions. They form what is often referred to as an 'electron sea'. These free moving electrons can carry charge from one place to another when a voltage (electric potential difference) is applied, making metals good conductors of electricity.

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Answer:

1. Partial pressure of N2 is 204.5 mmHg

2. Partial pressure of Cl2 is 613.5 mmHg

Explanation:

Step 1:

The equation for the reaction. This is given below:

NCl3 —> N2 (g) + Cl2 (g)

Step 2:

Balancing the equation.

NCl3 (l) —> N2 (g) + Cl2 (g)

The above equation is balanced as follow:

There are 2 atoms of N on the right side and 1 atom on the left side. It can be balance by putting 2 in front of NCl3 as shown below:

2NCl3 (l) —> N2 (g) + Cl2 (g)

There are 6 atoms of Cl on the left side and 2 atoms on the right side. It can be balance by putting 3 in front of Cl2 as shown below:

2NCl3 (l) —> N2 (g) + 3Cl2 (g)

Now the equation is balanced.

Step 2:

Determination of the mole fraction of each gas.

From the balanced equation above, the resulting mixture of the gas contains:

Mole of N2 = 1

Mole of Cl2 = 3

Total mole = 4

Therefore, the mole fraction for each gas is:

Mole fraction of N2 = mole of N2/total mole

Mole fraction of N2 = 1/4

Mole fraction of Cl2 = mole of Cl2/total mole

Mole fraction of Cl2 = 3/4

Step 3:

Determination of the partial pressure of N2.

Partial pressure = mole fraction x total pressure

Total pressure = 818 mmHg

Mole fraction of N2 = 1/4

Partial pressure of N2 = 1/4 x 818

Partial pressure of N2 = 204.5 mmHg

Step 4:

Determination of the partial pressure of Cl2.

Partial pressure = mole fraction x total pressure

Total pressure = 818 mmHg

Mole fraction of Cl2 = 3/4

Partial pressure of Cl2 = 3/4 x 818

Partial pressure of Cl2 = 613.5 mmHg

Answer:

[tex]p_{N_2}=204.5mmHg\\p_{Cl_2}=613.5mmHg[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]2NCl_3(g)\rightarrow N_2(g)+3Cl_2(g)[/tex]

Thus, by knowing that the nitrogen trichloride is completely decomposed, one assumes there is one mole of nitrogen and three moles of chlorine (stoichiometric coefficients) as a basis to compute the partial pressures since they have the mole ratio from the nitrogen trichloride. Hence, the mole fractions result:

[tex]x_{N_2}=\frac{1}{1+3}=0.25\\ x_{Cl_2}=1-0.25=0.75[/tex]

In such a way, for the final pressure 818 mmHg, the partial pressures become:

[tex]p_{N_2}=x_{N_2}p_T=0.25*818mmHg=204.5mmHg\\p_{Cl_2}=x_{Cl_2}p_T=0.75*818mmHg=613.5mmHg[/tex]

Best regards.

Final answer:

The E2 reaction is a type of elimination mechanism where a base removes a proton from a carbon adjacent to one with a leaving group, leading to the creation of a double bond. It requires the bonds to be anti-aligned and uses a bulky base to favor the formation of more highly substituted alkenes, with no intermediates formed.

Explanation:

The E2 elimination reaction is a concerted process where a base removes a proton (H) adjacent to a carbon with a leaving group (often denoted as 'X'), resulting in the formation of a double bond. The key characteristics of the E2 mechanism include the requirement for the C-H and C-X bonds to be in an anti-periplanar arrangement, ensuring they are aligned properly for the elimination to occur. Additionally, the use of a bulky base typically leads to the formation of the more highly substituted alkene product, favoring the more stable Zaitsev product. There is also no carbocation intermediate in the E2 mechanism; instead, the reaction proceeds through a single concerted step without intermediates. The E2 mechanism is typically observed with secondary and tertiary substrates where steric hindrance inhibits SN2 reactions.

Answer: the effects of cholera toxin on cAMP in the intestinal cells is that it INCREASES cAMP production.

Explanation:

Vibrio cholerae is a gram negative bacterium which produces a protein cholera toxin that is responsible for the characteristic symptoms of cholera such as

watery diarrhea, vomiting, rapid heart rate, loss of skin elasticity, low blood pressure, thirst, and muscle cramps. There is need for body fluids and Na replacement to avoid severe dehydration results which may lead to death.

Cyclic adenosine monophosphate( cAMP) is a derivative used for intracellular signal transduction in organisms. The cholera toxin produced by the bacteria INCREASES the production of cAMP through its polypeptides( which consist of active protomer and binding protomer). The cholera toxin first binds to cell surface receptors, the protomer then enters the cell and bind with and activate the adenylate cyclase. Increasing adenylate cyclase activity will INCREASE cellular levels of cAMP, increasing the activity of ion pumps that remove ions from the cell. Due to osmotic pressure changes, water also must flow with the ions into the lumen of the intestinal mucosa, dehydrating the tissue. I hope this helps, thanks.

Answer:

Explanation:

Check below for the answer in the attachment.

d. HF is an acid and  [tex]F^-[/tex] is its conjugate base.

What is acid/ base and its conjugate acid/base?

Given chemical reaction:

[tex]HF(aq) + HPO_4^{2-}(aq)----> F^-(aq) + H_2PO_4^-(aq)[/tex]

In this reaction, HF is an acid and its conjugate base is [tex]F^-[/tex].

Thus out of all the options; the correct option is d.

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In the reaction HF(aq) + HPO4^2-(aq) = F^-(aq) + H2PO4^-(aq), HF is the acid and F^- is the conjugate base, making the correct answer (d).

In the given reaction HF(aq) + HPO42-(aq) = F-(aq) + H2PO4-(aq), we need to identify the correct acid-base pairs. When looking at this reaction, HF donates a proton (H+) to form its conjugate base F-, which makes HF the acid. On the other hand, since HPO42- receives a proton (H+) to become H2PO4-, HPO42- clearly acts as the base in this reaction and H2PO4- is its conjugate acid, which shows that it is amphoteric.

Based on this explanation, the correct answer is (d) HF is an acid and F- is its conjugate base.

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Answer:

Explanation:

the question has been solve below

The balanced overall reaction is Mn(s) + Pb²⁺ (aq) → Mn²⁺ (aq) + Pb(s) with a standard cell potential of 1.050 V, making option a) the correct choice.

To answer this, let's first identify the standard cell potential (E°) for the given half-reactions:

Mn²⁺ (aq) + 2 e⁻ → Mn(s); E° = –1.180 V

Pb²⁺ (aq) + 2 e⁻ → Pb(s); E° = –0.130 V

In an electrochemical cell, the half-reaction with the more positive reduction potential acts as the cathode (reduction), and the one with the less positive potential acts as the anode (oxidation). Here, E° for Pb²⁺/Pb is more positive (-0.130 V) than E° for Mn²⁺/Mn (-1.180 V).

Therefore, the cell setup will be:
Manganese will be oxidized: Mn(s) → Mn²⁺ (aq) + 2 e⁻ (oxidation at the anode)
Lead will be reduced: Pb²⁺ (aq) + 2 e⁻ → Pb(s) (reduction at the cathode)

The balanced overall reaction:

Mn(s) + Pb²⁺ (aq) → Mn²⁺ (aq) + Pb(s)

Calculating the Cell Potential:

The standard cell potential (E°cell) is calculated as follows:

E°cell = E°cathode - E°anode
E°cell = (-0.130 V) - (-1.180 V) = 1.050 V

So, the correct answer is:

a) Pb²⁺(aq) + Mn(s) → Pb(s) + Mn²⁺(aq); E° = 1.050 V

Complete question:

Which of the following is the balanced overall reaction and standard cell potential of an electrochemical cell constructed from half-cells with the given half reactions? Mn 2+(aq) + 2 e−→Mn(s); E° = –1.180 V Pb2+(aq) + 2 e−→ Pb(s); E° = –0.130 V Group of answer choices

a) Pb 2+(aq) + Mn(s) →Pb(s) + Mn2+(aq); = 1.050 V

b) Pb(s) + Mn2+(aq) →Pb2+(aq) + Mn(s); = −1.050 V

c) Pb 2+(aq) + Mn2+(aq) →Pb(s) + Mn(s); = –1.310 V

d) Pb 2+(aq) + Mn(s) →Pb(s) + Mn2+(aq); =0.525 V

e) Pb(s) + Mn2+(aq) →Pb2+(aq) + Mn(s); = −0.525 V

Answer:

a) Balanced Overall Stoichiometric Equation

CHCl₃(g) + Cl₂(g) → CCl₄(g) + HCl(g)

b) The reaction intermediates include Cl(g) and CCl₃(g)

c) The rate of reaction of the rate determining step is:

Rate = k [CHCl₃] [Cl]

d) The rate of overall reaction is given as

Rate = K [CHCl₃] √[Cl₂]

e) The reaction rate increases by a multiple of 2√2 when the reactants' concentrations are doubled.

Explanation:

Step 1: Cl₂(g) → 2Cl(g) fast

Step 2: CHCl₃(g) + Cl(g) → CCl₃(g) + HCl(g) slow

Step 3: CCl₃(g) + Cl(g) → CCl₄(g) fast

a) The overall reaction is a reaction between Chloroform (CHCl₃) and Chlorine (Cl₂). It can be obtained by summing all the elementary equations and eliminating the reaction intermediates (the species that appear on both sides upon summing up all the elementary equations).

Cl₂(g) + CHCl₃(g) + Cl(g) + CCl₃(g) + Cl(g) → 2Cl(g) + CCl₃(g) + HCl(g) + CCl₄(g)

Now, eliminating the reaction intermediates (the species that appear on both sides upon summing up all the elementary equations), we are left with

Cl₂(g) + CHCl₃(g) → HCl(g) + CCl₄(g)

CHCl₃(g) + Cl₂(g) → CCl₄(g) + HCl(g)

b) Like I mentioned in (a), the reaction intermediates are the species that appear on both sides upon summing up all the elementary equations. They include:

Cl(g) and CCl₃(g)

c) The rate determining step is usually the slowest step among the elementary equations.

The rate of reaction expression is usually written from the slowest step.

The slowest step is step 2.

CHCl₃(g) + Cl(g) → CCl₃(g) + HCl(g) slow

The rate of reaction is then given as

Rate = k [CHCl₃] [Cl]

d) The rate of reaction for the overall reaction is obtained by substituting for any intermediates that appear in the rate of reaction for the rate determining step

The rate of reaction of the rate determining step is:

Rate = k [CHCl₃] [Cl]

But we can substitute for [Cl] by obtaining an expression for it from the step 1.

Step 1: Cl₂(g) → 2Cl(g)

K₁ = [Cl]²/[Cl₂]

[Cl]² = K₁ [Cl₂]

[Cl] = √{K₁ [Cl₂]}

We then substitute this into the rate determining step

Rate = k [CHCl₃] [Cl]

Rate = k [CHCl₃] √{K₁ [Cl₂]}

Rate = (k)(√K₁) [CHCl₃] √[Cl₂]

Let (k)(√K₁) = K (the overall rate constant)

Rate = K [CHCl₃] √[Cl₂]

e) If the concentrations of the reactants are doubled, by what ratio does the reaction rate change

Old Rate = K [CHCl₃] √[Cl₂]

If the concentrations of the reactants are doubled, the new rate would be

New Rate = K × 2[CHCl₃] × √{2 × [Cl₂]}

New Rate = K × 2[CHCl₃] × √2 × √[Cl₂]

New Rate = 2√2 K [CHCl₃] √[Cl₂]

Old Rate = K [CHCl₃] √[Cl₂]

New Rate = 2√2 × (Old Rate)

The reaction rate increases by a multiple of 2√2 when the reactants' concentrations are doubled.

Hope this Helps!!!!

Answer: 41.2 atm

Explanation

To calculate the final pressure of the system, we use the equation given by Gay-Lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]

where,

[tex]P_1\text{ and }T_1[/tex] are the initial pressure and temperature of the gas.

[tex]P_2\text{ and }T_2[/tex] are the final pressure and temperature of the gas.

We are given:

[tex]P_1=30.0atm\\T_1=20.3^0C=(20.3+273)=293.3K\\P_2=?\\T_2=130^0C=(130+273)K=403K[/tex]

Putting values in above equation, we get:

[tex]\frac{30.0}{293.3K}=\frac{P_2}{403}\\\\P_2=41.2atm[/tex]

The maximum pressure (in atm) that will be attained in the tank before the plug melts and releases gas is 41.2

The maximum pressure (in atm) that will be attained in the tank before the plug melts and releases gas is 41.22 atm

From the question given above, the following data were obtained:

Initial pressure (P₁) = 30 atm

Initial temperature (T₁) = 20.3 °C = 20.3 + 273 = 293.3 K

Final temperature (T₂) = 130 °C = 130 + 273 = 403 K

The final pressure can be obtained as illustrated below:

[tex]\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}\\\\\frac{30}{293.3} = \frac{P_{2}}{403}\\\\[/tex]

Cross multiply

293.3 × P₂ = 30 × 403

293.3 × P₂ = 12090

Divide both side by 293.3

[tex]P_{2} = \frac{12090}{293.3} \\\\[/tex]

Therefore, the maximum pressure (in atm) that will be attained in the tank before the plug melts and releases gas is 41.22 atm

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Answer:

58.72 mL

Explanation:

The chemical equation for the neutralization reaction is :

H₂SO₄(aq) + Na₂CO₃(s)  --------------> Na₂SO₄(aq) + H₂O(l) + CO₂(g)

where;

M₁ = Molarity of H₂SO₄

M₂= Molarity of Na₂CO₃

V₁= Volume of H₂SO₄

V₂ = Volume of Na₂CO₃

Given that :

M₁ = 18.4 M

V₁= 0.3 mL

10% Na₂CO₃ means 100 g of solution contain 10 g of Na₂CO₃

i.e. 10 g Na₂CO₃ dissolved and diluted to 100 mL water.

Molar mass of Na₂CO₃ = 106 g/mol

106 g Na₂CO₃ dissolved in 100 mL will give 0.1 M Na₂CO₃ solution.

However;

If, 106 g Na₂CO₃ ≡ 0.1 M Na₂CO₃

Then, 10 g Na₂CO₃ ≡  'A' M  of Na₂CO₃

By cross multiplying; we have:

106 × A = 10 × 0.1

106 × A = 1

A = (1/106) M/100 mL

A = 10 x (1/106)) M/L

A = (10/106) M

A = 0.094  M

Therefore,the molarity of 10% Na₂CO₃ solution is 0.094 M.

For the Neutralization equation, we have:

M₁V₁ = M₂V₂

18.4×0.3 = 0.094×V₂

Making V₂  the subject of the formula;we have:

[tex]V_2 = \frac{18.4*0.3}{0.094}[/tex]

V₂ = 58.72 mL

Answer:

pH= 13.03

Explanation:

Since dissociation of Sr(OH)2= Sr2+ + 2[OH-]

[OH-]=2×0.0538 = 0.1076M

pOH= -log[0.1076]= 0.97

pH= 14-pOH = 14-0.97= 13.03

Answer:

The empirical formula is C3H6O

Explanation:

Step 1: Data given

Mass of the sample =2.088 grams

The mass contains carbon, hydrogen, and oxygen

Mass of CO2 produced = 4.746 grams

Mass of H2O produced = 1.943 grams

Molar mass of CO2 = 44.01 g/mol

Molar mass of H2O = 18.02 g/mol

Atomic mass of C = 12.01 g/mol

Atomic mass of H = 1.01 g/mol

Atomic mass of O = 16.0 g/mol

Step 2: Calculate moles CO2

Moles CO2 = mass CO2 / molar mass CO2

Moles CO2 = 4.746 grams/ 44.01 g/mol

Moles CO2 = 0.1078 moles

Step 3: Calculate moles C

For 1 mol CO2 we have 1 mol C

For 0.1078 moles CO2 we'll have 0.1078 moles C

Step 4: Calculate mass C

Mass C: moles C * atomic mass C

Mass C: 0.1078 moles * 12.01 g/mol

Mass C= 1.295 grams

Step 5: Calculate moles H2O

Moles H2O = 1.943 grams / 18.02 g/mol

Moles H2O = 0.1078 moles

Step 6: Calculate moles H

For 1 mol H2O we'll have 2 moles H

For 0.1023 moles H2O we'll have 2*0.1078 = 0.2156 moles H

Step 7: Calculate mass H

Mass H = 0.2046 moles * 1.01 g/mol

Mass H = 0.218 grams

Step 8: Calculate mass O

Mass O = 2.088 grams - 1.295 grams - 0.218 grams

Mass O = 0.575 grams

Step 9: Calculate moles O

Moles O = 0.575 grams / 16.0 g/mol

Moles O = 0.0359 moles

Step 10: Calculate the mol ratio

We divide by the smallest amount of moles

C: 0.1078 moles / 0.0359 moles = 3

H: 0.2156 moles / 0.0359 moles = 6

O: 0.0359 moles / 0.0359 moles =1

The empirical formula is C3H6O

The empirical formula of the compound is C₃H₆O

We'll begin by calculating the mass of C, H and O in the compound. This can be obtained as follow:

Mass of CO₂ = 4.746 g

Molar mass of CO₂ = 44 g/mol

Molar mass of C = 12 g/mol

Mass of C = 12/44 × 4.746

Mass of H₂O = 1.943 g

Molar mass of H₂O  = 18 g/mol

Molar mass of H₂ = 1 × 2 = 2 g/mol

Mass of H = 2/18 × 1.943

Mass of C = 1.294 g

Mass of H = 0.216 g

Mass of compound = 2.088 g

Mass of O = (Mass of compound ) – (mass of C + mass of H)

Mass of O = 2.088 – (1.294 + 0.216)

C = 1.294 g

H = 0.216 g

O = 0.578 g

Divide by their molar mass

C = 1.294 / 12 = 0.108

H = 0.216 / 1 = 0.216

O = 0.578 / 16 = 0.036

Divide by the smallest

C = 0.108 / 0.036 = 3

H = 0.216 / 0.036 = 6

O = 0.036 / 0.036 = 1

Therefore, the empirical formula of the compound is C₃H₆O

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Answer:

S = 0.00014 moles /L = 1.4 * 10^-4 moles/L

Explanation:

Step 1: Data given

Temperature = 25.0 °C

Ksp = 1.1 * 10^-11

Step 2: The balanced equation

Mg(OH)2(s) ⇆ Mg^2+(aq) + 2OH-(aq)

Step 3: Define Ksp

[Mg(OH)2 = 1.11 * 10^-11 = S

[Mg^2+] = S

[OH-] = 2S

Ksp = [Mg^2+]*[OH-]²

Ksp = S * (2S)²

1.1 * 10^-11 = 4S³

S³ = 2.75 * 10^-12

S = 0.00014 moles /L

Answer:

21,976 J

Explanation:

In order to increase the temperature of a certain amount of a substance by [tex]\Delta T[/tex], the amount of heat that must be supplied to the substance must be:

[tex]Q=mC\Delta T[/tex]

where

m is the mass of the substance

C is the specific heat capacity of the substance

[tex]\Delta T[/tex] is the increase in temperature

For the sample of water in this problem we have:

[tex]m=150.0 g[/tex] is the mass

[tex]C=4.186 J/g^{\circ}C[/tex] is the specific heat capacity of water

[tex]\Delta T=60.0-25.0=35.0^{\circ}C[/tex] is the increase in temperature

Therefore, the amount of heat that must be supplied is

[tex]Q=(150.0)(4.186)(60-0-25.0)=21,976 J[/tex]

To heat 150.0 g of water from 25.0°C to 60.0°C, approximately 21885 joules of heat must be absorbed, calculated using the formula q = mcΔT with the values m = 150.0 g, c = 4.18 J/gK, and ΔT = 35.0°C.

The amount of heat required to raise the temperature of 150.0 g of water from 25.0°C to 60.0°C can be calculated using the formula q = mcΔT, where q is the heat absorbed, m is the mass of the water, c is the specific heat capacity of water, and ΔT is the change in temperature.

Using the given values, the mass m = 150.0 g, specific heat capacity c = 4.18 J/gK, and the temperature change ΔT = (60.0 - 25.0)°C = 35.0°C, we get:

q = (150.0 g)(4.18 J/gK)(35.0 K)

q = 150.0 g * 4.18 J/g°C * 35.0°C

q = 21885 J

Therefore, the water must absorb approximately 21885 joules of heat for the temperature to increase from 25.0°C to 60.0°C.

Answer: Number of balloons that can be filled with He are 1397.

Explanation:

The given data is as follows.

      V = 25 L He ,          P = 131 atm

      T = [tex]19^{o}C[/tex] = (19 + 273) K

          = 292 K

According to ideal gas equation,

            PV = nRT

where,     n = [tex]\frac{PV}{RT}[/tex]

                   = [tex]\frac{131 \times 25}{0.082 \times 292}[/tex]

                   = 136.76 mol of He

The data for small balloons is given as follows.

        T = [tex]27^{o}C[/tex] = (27 + 273) K

                   = 300 K

        P = 732 = 0.963 atm

        V = 2.50 L

Now, we will calculate the number of moles as follows.

       n = [tex]\frac{PV}{RT}[/tex]

          = [tex]\frac{0.963 \times 2.50}{0.082 \times 300}[/tex]

         = 0.098 mol

So, number of balloons that can be filled with He are calculated as follows.

         n = [tex]\frac{N_{1}}{N_{2}}[/tex]

            = [tex]\frac{136.76}{0.098}[/tex]

            = 1397.60 balloons

or,        = 1397 balloons (approx)

Thus, we can conclude that number of balloons that can be filled with He are 1397.

Answer:

Explanation:

Hydroponics is the process of growing crops using only water and liquid fertilizer. This process is great when your in the big city.

Hydroponics is a method of growing plants in a nutrient-rich water solution rather than soil, which allows precise control of nutrients and is used in research and commercial greenhouses for robust crop production.

Hydroponics is a highly efficient farming technique where plants are grown in a water-nutrient solution, rather than in soil. This method allows for precise control over the nutritional environment of the plants, which is why it is favored in scientific research for studying plant nutrient deficiencies and for producing robust, healthy crops.

In hydroponic systems, the need for soil is eliminated, and plants are given the exact nutrients they require directly. Because of this, hydroponics is used not only in laboratories but also in commercial greenhouse environments to cultivate flowers, vegetables, and other crops.

These crops are often resilient to pests and harsh conditions, contributing to sustainable food production and agricultural development.

Greenhouse management and hydroponics go hand in hand, as many plants grown hydroponically are also cultivated under controlled climates within greenhouses. The elimination of soil in hydroponics also helps mitigate the ecological, economic, and health concerns associated with excessive pesticide use in traditional agriculture.

Answer:

Explanation:

Using Dalton's law of partial pressure

P total pressure = Pressure of helium + Pressure of neon + Vapor pressure of water

P = 28.3 mmHg, Pressure of helium = 381 mmHg, Vapor pressure of water at 28°C

791 mmHg - 381 mmHg - 28.3 mmHg = Pressure of neon

Pressure of neon = 381.7 mmHg

Answer:

group

Explanation:

elements in the same group have the same number of valence electrons

There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Therefore, the correct option is option C.

Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.

Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.

Within each group in the periodic table, elements have similar properties because they have the same number of valence electrons.

Therefore, within each group in the periodic table, elements have similar properties because they have the same number of valence electrons. The correct option is option C.

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Answer:

28.58 g of NaOH

Explanation:

The question is incomplete. The missing part is:

"Calculate the mass of sodium hydroxide that the chemist must weigh out in the second step"

To do this, we need to know how much of the base we have to weight to prepare this solution.

First we know that is a sodium hydroxide aqueous solution so, this will dissociate in the ions:

NaOH -------> Na⁺ + OH⁻

As NaOH is a strong base, it will dissociate completely in solution, so, starting with the pH we need to calculate the concentration of OH⁻.

This can be done with the following expression:

14 = pH + pOH

and pOH = -log[OH⁻]

So all we have to do is solve for pOH and then, [OH⁻]. To get the pOH:

pOH = 14 - 13.9 = 0.10

[OH⁻] = 10⁽⁻⁰°¹⁰⁾

[OH⁻] = 0.794 M

Now that we have the concentration, let's calculate the moles that needs to be in the 900 mL:

n = M * V

n = 0.794 * 0.9

n = 0.7146 moles

Finally, to get the mass that need to be weighted, we need to molecular mass of NaOH which is 39.997 g/mol so the mass:

m = 39.997 * 0.7146

Answer:

5:22 am

Explanation:

The gas X decays following a first-order reaction.

The half-life ([tex]t_{1/2}[/tex]) is 25 min. We can find the rate constant (k) using the following expression.

[tex]k = \frac{ln2}{t_{1/2}} =\frac{ln2}{25min} = 0.028 min^{-1}[/tex]

We can find the concentration of X at a certain time ([tex][X][/tex]) using the following expression.

[tex][X] = [X]_0 \times e^{-k \times t}[/tex]

where,

[tex][X]_0[/tex]: initial concentration of X

t: time elapsed

[tex]\frac{[X]}{[X]_0}= e^{-k \times t}\\\frac{1/10[X]_0}{[X]_0}= e^{-0.028min^{-1} \times t}\\t=82min[/tex]

The earliest time Professor Utonium can come back to do experiments in the lab is:

4:00 + 82 = 5:22 am

Final answer:

The earliest Professor Utonium can return to the lab after a radioactive release is approximately 5:15 am, based on the half-life of 25 minutes and the requirement for the concentration of the gas to drop by a factor of 10, corresponding to just over 3 half-lives.

Explanation:

The question asks for the earliest time Professor Utonium can return to the lab after a release of a radioactive gas, X, which has a half-life of 25 minutes, and the lab is considered safe when its concentration drops by a factor of 10. Understanding that the decay of the radioactive element follows first-order kinetics, we can calculate the time required for the concentration to drop by this factor.

First-order decay implies that the time it takes for a substance to decay to half its initial amount is constant, known as the half-life. To reduce the concentration of a substance by a factor of 10, we need to go through a certain number of half-lives. The formula for calculating the amount of substance remaining after a given time is N = N0,[tex](1/2)^{(t/t1/2)}[/tex] where N is the remaining amount, N0 is the initial amount, t is time, and t1/2 is the half-life.

To reduce the concentration by a factor of 10, we effectively need the substance to go through just over 3 half-lives (since (1/2)³ = 1/8, which is just a bit more than one-tenth). Therefore, the calculation is 3 * 25 = 75 minutes after the initial release. Since the accident happened at around 4:00 am, adding 75 minutes means the earliest Professor Utonium can return to the lab is approximately 5:15 am.

Answer:

27.60 g urea

Explanation:

The freezing-point depression is expressed by the formula:

In this case,

m is the molality of the urea solution in X (mol urea/kg of X)

First we calculate the molality:

Now we calculate the moles of urea that were dissolved:

550 g X ⇒ 550 / 1000 = 0.550 kg X

Finally we calculate the mass of urea, using its molecular weight:

Answer:

A. Kinetic energies of molecules increase.

B. Speeds of molecules increase.

C. Number of collisions per second increase.

Final answer:

Pressure changes according to Le Chatelier's principle and can be influenced by mechanical and thermal mechanisms, as well as by the kinetic activity of gas molecules.

Explanation:

Pressure changes can be understood in terms of Le Chatelier's principle, which states that when a change is imposed on a system at equilibrium, the system adjusts to counteract that change.

In the case of gases, increasing the pressure (by decreasing volume) leads to a shift in the equilibrium to reduce the number of gas particles, if possible, thereby reducing the pressure. Conversely, decreasing the pressure (by increasing volume) would have the opposite effect.

Pressure also varies due to thermal and mechanical mechanisms. Heating air causes it to rise and reduce surface air pressure, while cooling air causes it to descend, increasing pressure.

Mechanical changes occur when airflow is blocked, causing a build-up of air and increased pressure. Additionally, the kinetic theory of gases suggests that gases exert pressure because of the continuous motion of their particles, colliding with container walls and exerting force.

Furthermore, variations in pressure at different points of a fluid are important for driving the phenomena of buoyancy, as well as affecting divers and airplane passengers through changes in ambient pressure.

Answer:

All of the choices.

Explanation:

As the reaction is involving with a mixture of H₂O and CH₃OH, these two reagents can work as nucleophyle of the reaction. Both of them, are polar and promoves a Sn1/E1 reaction. When it reacts with water it will produce product B); it will form product C) when it reacts with methanol, and product A) will be formed when the reaction undergoes an E1 reaction.

In this case, the only way to show you this, it's doing the mechanism of reaction for each product. Picture attached show the mechanism for the formation of all these products.

Treating (CH3)3C-Cl with H2O and CH3OH usually results in the formation of tert-butyl alcohol, (CH3)3COH, through a nucleophilic substitution reaction, making option B the correct answer.

Treating (CH3)3C-Cl with a mixture of H2O and CH3OH at room temperature typically involves a nucleophilic substitution reaction where the chloride ion (Cl-) is replaced by the nucleophile. In this case, the nucleophiles are water (H2O) and methanol (CH3OH). The product of this reaction would be (CH3)3COH, also known as tert-butyl alcohol, as both water and methanol could act as nucleophiles to perform the substitution, but water is generally a better nucleophile than methanol. Hence, option B is the correct answer.

Answer:

The one that will begin to precipitate first will be the lead chromate (PbCrO₄)

Explanation:

First of all, let's determine the equations involved:

Pb(NO₃)₂ →   Pb²⁺  +   2NO₃⁻

0.001          0.001       0.002

Ba(NO₃)₂  →  Ba²⁺  +  2NO₃⁻

0.100          0.100      0.200  

Sodium chromate as a soluble salt, can be also dissociated in:

Na₂CrO₄ →  2Na⁺ +  CrO₄²⁻

As the chromate can react to both cations of the aqueous solution, there will be formed 2 precipitates. When the saturation point is reached, which is determined by the Kps, everything that cannot be dissolved will precipitate.

The first to saturate the solution will precipitate first.

CrO₄²⁻ + Pb²⁺  ⇄  PbCrO₄

  s            s             s²  = Kps

 Kps = s² ⇒ [CrO₄²⁻] . [Pb²⁺] =  2.80×10⁻¹³

[CrO₄²⁻] . 0.001 = 2.80×10⁻¹³

[CrO₄²⁻] = 2.80×10⁻¹³ / 0.001 = 2.80×10⁻¹⁰

This is the concentration for the chromate when the lead chromate starts to precpitate.

CrO₄²⁻ + Ba²⁺  ⇄  BaCrO₄

  s            s             s²  = Kps  

Kps = [CrO₄²⁻] . [Ba²⁺]

1.17×10⁻¹⁰ = [CrO₄²⁻] . 0.100

[CrO₄²⁻] = 1.17×10⁻¹⁰ / 0.100 =  1.17×10⁻⁹

The first one that precipitates needs less chromate ion to start precipitating, in conclusion the one that will begin to precipitate first will be lead chromate.

The solid that will precipitate first is PbCrO₄.

To determine which solid will precipitate first, we need to compare the solubility product constants [tex](\( K_{\text{sp}} \))[/tex] for each possible precipitate. The compound with the lower [tex]\( K_{\text{sp}} \)[/tex] will precipitate first because it has lower solubility in water.

The solubility products given are:

- [tex]\( K_{\text{sp}} \) of BaCrO\(_4\) = \( 1.17 \times 10^{-10} \)[/tex]

- [tex]\( K_{\text{sp}} \) of PbCrO\(_4\) = \( 2.80 \times 10^{-13} \)[/tex]

We need to find the concentration of [tex]\(\text{CrO}_4^{2-}\) (\([ \text{CrO}_4^{2-} ]\))[/tex] at which each compound will begin to precipitate.

Calculation for BaCrO₄:

The reaction for the precipitation of BaCrO₄ is:

[tex]\[ \text{Ba}^{2+} (aq) + \text{CrO}_4^{2-} (aq) \rightarrow \text{BaCrO}_4 (s) \][/tex]

The [tex]\( K_{\text{sp}} \)[/tex] expression is:

[tex]\[ K_{\text{sp}} = [\text{Ba}^{2+}] [\text{CrO}_4^{2-}] \][/tex]

Given:

[tex]\[ K_{\text{sp}} (\text{BaCrO}_4) = 1.17 \times 10^{-10} \][/tex]

[tex]\[ [\text{Ba}^{2+}] = 0.100 \, \text{M} \][/tex]

We can solve for [tex]\([ \text{CrO}_4^{2-} ]\)[/tex]:

[tex]\[ 1.17 \times 10^{-10} = (0.100) [\text{CrO}_4^{2-}] \][/tex]

[tex]\[ [\text{CrO}_4^{2-}] = \frac{1.17 \times 10^{-10}}{0.100} \][/tex]

[tex]\[ [\text{CrO}_4^{2-}] = 1.17 \times 10^{-9} \, \text{M} \][/tex]

Calculation for PbCrO₄:

The reaction for the precipitation of PbCrO₄ is:

[tex]\[ \text{Pb}^{2+} (aq) + \text{CrO}_4^{2-} (aq) \rightarrow \text{PbCrO}_4 (s) \][/tex]

The [tex]\( K_{\text{sp}} \)[/tex] expression is:

[tex]\[ K_{\text{sp}} = [\text{Pb}^{2+}] [\text{CrO}_4^{2-}] \][/tex]

Given:

[tex]\[ K_{\text{sp}} (\text{PbCrO}_4) = 2.80 \times 10^{-13} \][/tex]

[tex]\[ [\text{Pb}^{2+}] = 0.001 \, \text{M} \][/tex]

We can solve for [tex]\([ \text{CrO}_4^{2-} ]\)[/tex]:

[tex]\[ 2.80 \times 10^{-13} = (0.001) [\text{CrO}_4^{2-}] \][/tex]

[tex]\[ [\text{CrO}_4^{2-}] = \frac{2.80 \times 10^{-13}}{0.001} \][/tex]

[tex]\[ [\text{CrO}_4^{2-}] = 2.80 \times 10^{-10} \, \text{M} \][/tex]

Comparison:

- The concentration of [tex]\(\text{CrO}_4^{2-}\)[/tex] needed to precipitate BaCrO₄ is [tex]\( 1.17 \times 10^{-9} \, \text{M} \)[/tex].

- The concentration of [tex]\(\text{CrO}_4^{2-}\)[/tex] needed to precipitate PbCrO₄ is [tex]\( 2.80 \times 10^{-10} \, \text{M} \)[/tex].

Since [tex]\( 2.80 \times 10^{-10} \, \text{M} \)[/tex] is smaller than[tex]\( 1.17 \times 10^{-9} \, \text{M} \), PbCrO\(_4\)[/tex] will precipitate first.

Answer:

-- 5.8×10⁻⁹ of the H is in 2P states at T=5900 K, a typical Sun surface temperature.

-- 3.3×10⁻¹² of the H is in 2P states at T=4300 K, a typical Sunspot temperature.

Explanation:

Answer:

Explanation:

your question seems to be  uncompleted , but however i have a solution to a similar question, check the attachment and follow the format to evaluate your question.

check the attachement

Answer:

Ice and water on the ground affect incoming solar radiation by reflecting 4 percent of solar radiation that reaches the surface.

Explanation:

Answer:

ice and water on the ground affect incoming solar radiation by reflecting 4 percent of solar radiation that reaches the surface. the state of water and the sun angle are vital in determining the amount of reflection that take place. at low sun angle and at times when the surface is ice, more reflection occurs.

Explanation:

None

Answer:

Ni^2+ is most likely

Ti^3+ is very unlikely

Explanation:

The Crystal Field Stabilization Energy almost always favors octahedral over tetrahedral in very many cases, but the degree of this favorability varies with the electronic configuration. In other words, for d1 there is only a small gap between the octahedral and tetrahedral lines, whereas at d3 and d8 is a very big gap. However, for d0, d5 high spin and d10, there is no crystal field stabilization energy difference between octahedral and tetrahedral. The ordering of favorability of octahedral over tetrahedral is:

d3, d8 > d4, d9> d2, d7 > d1, d6 > d0, d5, d10. This explains the answer choices above.

Ti^3+ being a d1 specie is least likely to exist in octahedral shape while Ni2+ a d8 specie is more likely to exist in octahedral shape.

Answer:

Approximately [tex]0.47\; \rm mol \cdot L^{-1}[/tex] (note that [tex]1\; \rm M = 1 \; \rm mol \cdot L^{-1}[/tex].)

Explanation:

The molarity of a solution gives the number of moles of solute in each unit volume of the solution. In this [tex]\rm NaNO_3[/tex] solution in water,

Let [tex]n[/tex] be the number of moles of the solute in the whole solution. Let [tex]V[/tex] represent the volume of that solution. The formula for the molarity [tex]c[/tex] of that solution is:

[tex]\displaystyle c = \frac{n}{V}[/tex].

In this question, the volume of the solution is known to be [tex]1250\; \rm mL[/tex]. That's [tex]1.250\; \rm L[/tex] in standard units. What needs to be found is [tex]n[/tex], the number of moles of [tex]\rm NaNO_3[/tex] in that solution.

The molar mass (formula mass) of a compound gives the mass of each mole of units of this compound. For example, the molar mass of [tex]\rm NaNO_3[/tex] is [tex]85\; \rm g \cdot mol^{-1}[/tex] means that the mass of one mole of

[tex]\displaystyle n = \frac{m}{M}[/tex].

For this question,

[tex]\begin{aligned}&n\left(\mathrm{NaNO_3}\right) \\ &= \frac{m\left(\mathrm{NaNO_3}\right)}{M\left(\mathrm{NaNO_3}\right)}\\&= \frac{50\; \rm g}{85\; \rm g \cdot mol^{-1}} \\& \approx 0.588235\; \rm mol\end{aligned}[/tex].

Calculate the molarity of this solution:

[tex]\begin{aligned}c &= \frac{n}{V} \\&= \frac{0.588235\; \rm mol}{1.250\; \rm L} \\&\approx 0.47\;\rm mol \cdot L^{-1}\end{aligned}[/tex].

Note that [tex]1\; \rm mol \cdot L^{-1}[/tex] (one mole per liter solution) is the same as [tex]1\; \rm M[/tex].

Answer:

.47

Explanation:

just did it on CK-12

Answer:

1.52V

Explanation:

Oxidation half equation:

2Al(s)−→2Al^3+(aq) + 6e

Reduction half equation

3Sn2^+(aq) + 6e−→3Sn(s)

E°cell= E°cathode - E°anode

E°cathode= −0.140 V

E°anode= −1.66 V

E°cell=-0.140-(-1.66)

E°cell= 1.52V

Final answer:

The overall cell potential for the redox reaction between tin and aluminum in a galvanic cell is calculated as +1.52 V, indicating a spontaneous reaction with tin being oxidized at the anode and aluminum reduced at the cathode.

Explanation:

To calculate the standard cell potential for a redox reaction involving tin (Sn) and aluminum (Al), we apply the reduction potentials of their respective half-reactions. The half-reaction for tin is as follows: Sn(s) ightarrow Sn2+(aq) + 2 e - , with an associated standard reduction potential (E & Ocirc ;) of - 0.140 V, however, its oxidation potential is actually +0.140 V.

For aluminum, the half-reaction is: Al3+(aq) + 3 e - ightarrow Al(s), with an E & Ocirc ; of - 1.66 V. In a galvanic cell, the aluminum will oxidize, and since it’s a reduction potential, for oxidation, we take the negative of this value, which would make it +1.66 V.

To find the overall cell potential, we use the equation Ecell = Ecathode - Eanode. In this reaction, Sn(s) is our anode, and Al(s) is our cathode. However, since aluminum's E & Ocirc ; is already negative (signifying oxidation), we reverse its sign for use in the cell potential equation.

Ecell = Ecathode - Eanode = (+1.66 V) - (+0.14 V) = +1.66 V - 0.14 V = +1.52 V

The standard cell potential is positive, indicating that the redox reaction is spontaneous. Tin is oxidized at the anode, and aluminum is reduced at the cathode, forming the basis for electric current flow in the cell.