Calculate the pH of 720. mL of a 0.425-M solution of hydrocyanic acid before and after the addition of 0.249 mol of sodium cyanide.

Answer: 70 and above

Explanation:

This is a fact.

The pH of the solution will be 10.47.

The pH of a solution is mathematically given as:

 pH = - log [[tex]H^+[/tex]] of -log [[tex]H_3O^+[/tex]]

Thus, in this case, with  [[tex]H_3O^+[/tex]]  of 3.4 x 10-¹¹ M:

pH = -log 3.4 x [tex]10^-^1^1[/tex] = 10.47

Thus, the pH of the solution will be 10.47.

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Question 1

Fe(III) forms a chelate complex with salicylic acid which has purple color. therefore, when a solution is made either with salicylic acid or with aspirin having trae amount of salicylic acid in it, we see color formation in solution due to the resulting complex formed.

Question 2

The Fe(III) itself absorbs some light and gives an absorbance value for the solution. Therefore, it is necessary to blank the spectrophotometer with a Fe(III) solution prior to measurement of test solutions.

2. The new pressure, given the data is 3.0 atm

3. The new temperature in K is 361 K

4. The new temperature in K is 348 K

The new pressure of the gas can be obtained by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(3.4 × 1500) / 298 = (P₂ × 2000) / 348

Cross multiply

P₂ × 2000 × 298 = 3.4 × 1500 × 348

Divide both sides by 2000 × 298

P₂ = (3.4 × 1500 × 348) / (2000 × 298)

P₂ = 3.0 atm

The new temperature of the gas can be obtained by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(167 × 450) / 295 = (230 × 400) / T₂

Cross multiply

T₂ × 167 × 450 = 295 × 230 × 400

Divide both sides by 167 × 450

T₂ = (295 × 230 × 400) / (167 × 450)

T₂ = 361 K

The new temperature of the gas can be obtained by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(9.2 × 3.6) / 298 = (7.3 × 5.3) / T₂

Cross multiply

T₂ × 9.2 × 3.6 = 298 × 7.3 × 5.3

Divide both sides by 9.2 × 3.6

T₂ = (298 × 7.3 × 5.3) / (9.2 × 3.6)

T₂ = 348 K

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The amount of KNO₃ precipitated out of solution when you cooled the solution from 100°C to -22°C is obtained from the solubility curve

A solubility curve is a curve of the solubility of a solute against temperature.

The solubility curve shows that the solubility of different solute at different temperatures.

The solubility curve of KNO₃ is as shown. Solubility at 100 °C and  -22 °C is not shown in the curve.

However, the amount of KNO₃ precipitated out of solution when cooled the solution from 100 °C to -22 °C can be determined by subtracting the amount of solute dissolve at -22 °C from that dissolved at 100 °C.

In conclusion, the solubility curve is used to determined the amount of solute dissolved in a given volume of solvent at different temperatures.

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Answer: Anaphylaxis

Explanation:

I have a nut allergy, and this has happened to me once. The doctors also told me a lot about anaphylaxis, and I like to learn about myself.

I hope this helps!! :)

The formula of the metal oxide is FeO.

When a metal is burned in the air or oxygen the product formed is metal oxide. This is called the combustion reaction of metals.

Calculations:

It is given that the weight of iron (Fe) is 0.916 g. After the reaction, it forms iron oxide that has the weight 1.178 g. The weight of the metal before and after the reaction must have remained same, only the addition of oxygen has taken place.

The mass of oxygen is calculated as:

Mass of oxygen = 1.178 g - 0.916 g

= 0.262 g

The molar mass of oxygen is 16.00 g/mol. The number of moles of oxygen is calculated as:

Moles of O = 0.262 g/16.00 g/mol

= 0.0164 mol

The molar mass of Fe is 55.845 g/mol. The number of moles of Fe is calculated as:

Moles of Fe = 0.916 g/55.845 g/mol

= 0.0164 mol

The number of moles of Fe and O are equal. Hence, the molar ratio between Fe and O is 1:1. Therefore, the formula of the iron oxide is FeO.

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The solubility of the barium hydroxide after the addition of a 1M solution of barium nitrate is 0.035M

Barium nitrate is a salt that dissolves entirely in solution and is soluble. This indicates that before the salt dissolves, there will be a one molar concentration of barium ions. We may anticipate that the equilibrium will be pushed to the left and the barium hydroxide will be less soluble because we have increased the product side of the reaction. The common ion effect is the name given to this shift in equilibrium.

To ascertain the salt's solubility, we shall use an ICE table.

I. There is a one molar concentration of barium ions (from the barium nitrate) in the solution before the salt starts to dissolve, but there are no hydroxide ions present.

C. The unknown increases in each ion can be referred to as 1+ and 2x, respectively, because every dissolved molecule of barium hydroxide will produce one barium ion and two hydroxide ions. Observe how the previously added one molar concentration in the solution will be combined with the increased barium ion concentration.

E. At this point, we set the solubility equation to the constant representing the solubility product.

[tex]Ba(OH)_{2}[/tex] ⇔ [tex]Ba^{2+} + 2OH^{-}[/tex]

Ksp is defined as:

Ksp = [tex][Ba^{2+}] + [OH^{-}]^{2}[/tex]

5 x [tex]10^{-3}[/tex] = [tex][Ba^{2+}] [OH^{-}]^{2}[/tex]

It added a solution of 1M of [tex]Ba^{2+}[/tex]

5 x [tex]10^{-3}[/tex] = [tex][1M][/tex] [tex][OH^{-}]^{2}[/tex]

The addition of barium hydroxide [tex]Ba(OH)_{2}[/tex] gives:

[tex][Ba^{2+}] = 1M + x[/tex]

[tex][OH^{-}]^{2}[/tex] [tex]= 2x[/tex]

Replacing:

5x[tex]10^{-3}[/tex] = [tex][1+x][/tex] [tex][2x]^{2}[/tex]

[tex]10^{-3} = 4x^{2} + 4x^{3}[/tex]

[tex]x = 0.035 M[/tex]

Your question is incomplete, but most probably your full question was to consider the following balanced equation for the dissociation of barium hydroxide in an aqueous solution.

[tex]Ba(OH)_{2} (s) = Ba^{2+} (aq) + 2OH (aq)\\Ksp = 5* 10^{-3}[/tex]

A 1M solution of barium nitrate is added to the solution. What is the solubility of barium hydroxide after this addition?

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Answer:

[tex]\huge\boxed{\sf Single \ displacement \ reaction}[/tex]

Explanation:

There are 2 types:

[tex]\rule[225]{225}{2}[/tex]

Greenhouse gases act to increase temperatures by absorbing thermal infrared radiation.

We have already learned that Earth's atmosphere is composed often of nitrogen and oxygen. Those gases are transparent to incoming solar radiation. they may be also transparent to outgoing infrared radiation, which means that they do not take in or emit sun or infrared radiation.

The multiplied quantities of greenhouse gases human sports are adding to the environment have dissatisfied the balance that has been in location for the reason that ceases of the closing ice age, including greater greenhouse gases decreases the amount of infrared radiation energy leaving the atmosphere.

Greenhouse gases inside the ecosystem time and again absorb and re-radiate infrared radiation (warmth). strength radiated from Earth's surface as warmth, or infrared radiation is absorbed and re-radiated by using greenhouse gases, impeding the loss of warmth from our surroundings to area.

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The percent by mass of nitric acid in the mixture is 3.36 %

2 HNO3 + Ba(OH)2 --->Ba(NO3)2 + 2H2O

so 1 mole Ba(OH)2 neutralizes 2 mol HNO3

moles of Ba(OH)2 present = molarity of base* volume of base

= 0.229 M * 15.6 ml

= 3.5724 milli mols

mols of HNO3 neutralized = 2* mols of Ca(OH)2 used

= 2* 3.5724 milli mols = 7.1448 x10^-3 mols

molar mass of HNO3 = 63.01 g/mol

mass of HNO3 present = molar mass * mols of HNO3

= 63.01 g/mol * 7.1448 x10^-3 mols

=0.4502 g

mass of sample = 13.4 g

mass % = mass of HNO3/mass of sample * 100

= 0.4502/13.4 *100

= 3.36 %

Nitric acid is a colorless, fuming, and distinctly corrosive liquid that could be a not unusual laboratory reagent and an important commercial chemical for the manufacture of fertilizers and explosives.

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Answer:

Answer: 6.5 moles of silver metal is formed in the given chemical reaction. The moles of excess reagent left are 0.55 moles.

Explanation:

To calculate the moles of silver formed and the moles of excess reagent left after the reaction, we need to balance the equation first and need to find the limiting and excess reagent.

The balanced chemical equation is:

Zn + 2AgNO3 ---> Zn (NO3)2 +2Ag

By Stoichiometry:

2 moles of Silver nitrate reacts with 1 mole of Zinc metal

So, 6.5 moles of silver nitrate will react with = 1/2 x 6.5 = 3.25 moles of zinc metal

The required amount of zinc metal is less than the given amount of zinc metal,  hence, it is considered as an excess reagent.

Therefore, silver nitrate is the limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

2 moles of silver nitrate produces 2 moles of silver metal

So, 6.5 moles of silver nitrate will produce = 2/2 x 6.5 = 6.5moles of silver metal.

Number of moles of excess reagent left after the completion of reaction = (3.8 - 3.25)moles = 0.55 moles

Hence, 6.5 moles of silver metal is formed in the given chemical reaction. The moles of excess reagent left are 0.55 moles.

All of the following molecules except CH₃CH₂CH₃ make up a homologous series.

A homologous series is a series of compound having same general formula and same functional group.

The general formula of alkane is CₙH₂ₙ₊₂

The general formula of alkene is CₙH₂ₙ

CH₃CH₂CH₃ (Propane) is the third homologous series of alkane which satisfies the general formula of alkane.

Thus from the above conclusion we can say that All of the following molecules except CH₃CH₂CH₃ make up a homologous series.

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The total number of :

(a) p electrons in n (z=7) is 3

(b) s electrons in si (z=14) is 6

(c) 3d electrons in s (z=16) is 0

Electronic configuration:

The distribution of electrons in an element's atomic orbitals is described by the element's electron configuration. Atomic electron configurations adhere to a standard nomenclature in which all atomic subshells that contain electrons are arranged in a sequence with the number of electrons they each hold expressed in superscript.

The electronic configuration of z=7 (nitrogen) is 1s²2s²2p³

Total number of p electrons = 3

The electronic configuration of z=14 (silicon) is 1s²2s²2p⁶3s²3p²

Total number of s electrons = 2+2+2=6

The electronic configuration of z=16 (sulphur) is 1s²2s²2p⁶3s²3p⁴

Total number of 3d electrons = 0

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Answer:

3, 6, 0

Explanation:

Correct option:

The elements form ions with multiple charges is given by option B and D, i.e., Iron and Cobalt

The electronic configurations of elements(assumed):

[tex]A. \,Zinc\,-[Ar]\,3d^{10}4s^{2}\\\\B.\,Iron\,-[Ar]3d^64s^2\\\\C.\, Sodium\, [Ne]3s^1\\\\D.\,Cobalt\,[Ar]3d^74s^2\\\\E.\,Silver\,[Kr]4d^{10}5s^1[/tex]

These electronic configurations are based many factors-

1. (n+l) energy rule which states higher the value of (n+l), higher will be the energy of the orbital.

2. Fully filled and half filled orbitals are more stable than partially filled orbitals.

Now,

Elements of d-block have multiple oxidation states. Zinc has fully filled d-orbitals. It is not considered as d-block metal as it has only 1 oxidation state, i.e, +2.

Sodium exists only in +1 oxidation state.

Also Silver exists in +1 oxidation state.

So, the correct answer is Iron and Cobalt which can form ions with multiple charges.

Correct options are B and D.

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The flotation process used in metallurgy involves the separation of gangue from ore.

The various wettability qualities of a material's surface are the foundation of flotation operations. The basic principles of flotation are quite similar to those of a sink and float process, where the materials' relative densities to the medium in which they are deposited determine the basis of the separation.

Mineral processing, mineral dressing, or ore dressing are all terms for the process of separating minerals from gangue. It is an important and frequently necessary part of mining. Depending on the type of minerals used, the process may be difficult.

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[tex]\\ \tt\leadsto pH=-log[H^+][/tex]

[tex]\\ \tt\leadsto -log[H^+]=13.2[/tex]

[tex]\\ \tt\leadsto log[H^+]=-13.2[/tex]

[tex]\\ \tt\leadsto [H^+]=antilog(-13.2)=6.3\times 10^{-14}M[/tex]

The  concentration of [H3O+] will be 6.3 x [tex]10^{-14}[/tex] M

Mathematically, pH = -log [H+] or -log [H3O+]

With a pH of 13.2:

      -log [H3O+] = 13.2

                     log [H3O+] = -13.2

                         [H3O+] = 6.3 x [tex]10^{-14}[/tex] M

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The number of formula units in 116 g of NaCl is 1.204×10²⁴ formula units

1 mole of NaCl = 6.02×10²³ formula units

But

1 mole of NaCl = 58 g

Thus,

58 g of NaCl = 6.02×10²³ formula units

58 g of NaCl = 6.02×10²³ formula units

Therefore,

116 g of NaCl = (116 × 6.02×10²³) / 58

116 g of NaCl = 1.204×10²⁴ formula units

Thus, 1.204×10²⁴ formula units are present in 116 g of NaCl

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Fission nuclear reactions differ from fusion nuclear reactions because fission reactions involve the conversion of matter into energy (option 1).

Nuclear fission is a nuclear reaction in which a large nucleus splits into smaller ones with the simultaneous release of energy.

On the other hand, nuclear fusion is the combining of the nuclei of small atoms to form the nuclei of larger ones, with a resulting release of large quantities of energy.

Therefore, fission nuclear reactions differ from fusion nuclear reactions because fission reactions involve the conversion of matter into energy.

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Answer:

C

Explanation:

If the products have a higher energy level than the reactants then the reaction is endothermic.

In an endothermic reaction, the reaction mixture absorbs heat from the surroundings. Therefore, the products will have a higher energy than the reactants and ΔH will be positive.

In an exothermic reaction, the reaction mixture releases heat to the surroundings. Therefore, the products will have a lower energy than the reactants and ΔH will be negative.

Answer:

This description needs a unit describing the system of measurement.

The metal cationic (+) atom to nonmetal anionic (-) atom ratio in the compound formed between Potassium and Chlorine is 1:1.

A compound is made up of two or more atoms that are chemically combined together. In this case, we have the atoms; Potassium and Chlorine.

The electronic configuration of the atoms is not shown here but the metal cationic (+) atom to nonmetal anionic (-) atom ratio in the compound formed between Potassium and Chlorine is 1:1.

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Answer:

instructed 20 students to do what

Explanation:

Answer:

49.41° C

Explanation:

DeltaQ = m c T

  3044  = 1320  *  .16   *  T         where T is the temperature change

     T = 14.41

35 + 14.41 =  49.41 C

The three components of an expressway entrance are the Entrance ramp, acceleration lane, and merging area.

An expressway is a road that is specifically designed for high-speed traffic. These roads often have few crossings, few places of access or departure, and a divider between lanes for opposing-direction traffic.

It was mainly designed to make it easier for traffic to move at high speeds and in huge volumes.

Freeways, parkways, and turnpikes are examples of expressways. A highway is a primary route, but an expressway is a multilane highway.

Its principal objective was to facilitate the movement of heavy, fast-moving vehicles.

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The mass of CaCl2 is 0.076gram.

The molar mass of a compound is just the molar hundreds of every detail inside the compound brought up. Since the molar mass of Calcium is 40.08 g and the molar mass of Chlorine is 35.45, it might be 40g.08g+35.45g+35.45g (with 2 Chlorines in step with the subscript.) That leaves you with 110.98 g

Calcium and chlorine are the 2 factors in our instance. The molar loads of Ca (forty.08g/mol) and Cl (35.45g/mol) need to then be determined. Now that we have the masses of calcium and each chlorine atom, we are able to truly place them together to get the whole compound's molar mass, which is a hundred and 10.98 g/mol.

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The original temperature of the copper sample, assuming that all the heat lost by the copper is gained by the water is 147.08°C.

The temperature in a calorimetry experiment can be calculated using the following formula:

Q = mc∆T

Where;

For a calorimetry;

Q(water) = -Q(metal)

mc∆T (water) = -(mc∆T) (metal)

100 × 4.18 × 4.6 = - (80 × 0.20 × {26.9 - x}

1922.8 = -430.4 + 16x

16x = 2353.2

x = 147.08°C

Therefore, the original temperature of the copper sample, assuming that all the heat lost by the copper is gained by the water is 147.08°C.

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Diagnosis of Mrs. Smith:

Diagnosis for Mrs. Smith for having CK: moderately increased LD: moderately increased LD-1: increased symptoms is "Myocardial infarction".      

Myocardial infarction:

A myocardial infarction, commonly known as a heart attack, occurs when the blood supply to a portion of the heart muscle is inadequate or the cardiac muscle isn't getting enough oxygen in one or more places. The more time that goes by without receiving care to improve blood flow, the more damage the heart muscle sustains.

The majority of myocardial infarctions are brought on by underlying coronary artery disease, which deprives the myocardium of oxygen when coronary arteries are blocked. Myocardial necrosis and cell death can occur if the myocardium is continuously deprived of oxygen.

Signs of myocardial infarction:

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What is the legal limit?

The lowest concentration that can officially be reported for any constituent in drinking water is known as the "Legal Limit".

Contamination of water:

The level that safeguards human health and that water systems can attain with the finest technology is reflected in the regulatory limit for a contaminant.

How does it occur:

In order to control corrosion, the system must take a variety of additional measures if lead concentrations reach an action threshold of 15 ppb or copper concentrations exceed an action level of 1.3 ppm in more than 10% of measured customer taps.

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Correct option:

The molecular structure of NCl3 is a. pyramidal

Molecular structure of NCl3:

The molecular geometry of NCl3 can also be ascertained using the AXN approach.

The center atom in the NCl3 lewis dot structure is nitrogen, which possesses three pairs of bound electrons as well as one single electron.

Consequently, the NCl3 formula becomes AX3N1.

Therefore, if a molecule has the formula AX3N1, its shape is trigonal pyramidal, and its electron geometry is tetrahedral, according to the VSEPR chart and it undergoes [tex]sp^{3}[/tex] hybridization.

Reasons for incorrect options:

b. None of these: As pyramidal is one of the options given in the question. So, none of these is incorrect.

c. Octahedral: Electron geometry takes into account both bond pairs and lone pairs of electrons, whereas molecular geometry solely takes into account electrons' bonds when determining the structure of any molecule. As NCl3 has three bound pairs and one unpaired pair. Therefore, NCl3's electron geometry is tetrahedral while its molecular geometry is trigonal pyramidal, as seen by the VSEPR chart. Hence, octahedral is an incorrect option.

d. trigonal planar: If a molecule has three atoms or groups bound to a central atom and no lone electron pairs, it is said to be trigonal planar. But here in NCl3, it has three atoms and one lone electron pair. So, trigonal planar is not the correct option for NCl3.

e. bent: The lone pair on nitrogen generates repulsion between bond pairs and the lone pair, which causes the bond angle of NCl3 to slightly decreasing, making it 107.1°. Because of the lone pair on the nitrogen, which causes electrons to repel one another and bent the structure overall, NCl3 has a slight polarity. This permanent dipole moment is caused by the unequal charge distribution within the structure. But trigonal pyramidal is best to describe the molecular structure of NCl3. Hence is an incorrect option.

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