Please help meee! Chemistry!

Answer:

storage solution , deionized water, stabilizes

Explanation:

A pH meter is a scientific device or instrument that is used to measure the pH of a given aqueous solution thereby determining the nature of the solution whether it is acidic or basic or neutral.

While using the pH meter or taking the measurement using the pH meter --

The question is incomplete, the complete question is shown in the image attached to this answer

Answer:

1) K

2) F

3) Si

4) Br

Explanation:

If an element has a more negative value of electron affinity, then it has a greater ability to attract an electron.

In each of the following pairs of elements, one element has a more negative electron affinity for certain reasons.

Between K and Ca, the incoming electron in K goes into a 4s orbital which is lower in energy and more stable. For Ca, the electron goes into a 3d orbital which is more unstable.

Between Ne and F, Ne already has a filled outermost shell hence the incoming electron goes into the higher energy 3s level. In F, the electron goes into the 2p level and completes it. Hence F has a more negative electron affinity.

Let us recall that half filled and completely filled orbitals are exceptionally stable. Hence, the electron affinity of Si is more negative than that of P because in P, the electron goes into an exceptionally stable half filled orbital.

Recall that the more the value of Zeff, the more negative the electron affinity hence electron affinity increases across a period; hence, Br has a more negative value of electron affinity than Se.

Answer:

Explanation:

The density of pure water is 1 gram per 1 milliliter or one cubic cm. By knowing the density of water we can use it in dilution equations or to calculate the specific gravity of other solutions.

It can also help us determine what other substances are made of using the water displacement experiment. This is done by observing how much water is displaced when an object is submerged in the water. As long as you know the density of the water, the mass of the object being submerged and the volume of increase you can calculate the density of the object.

This was done by the great Archimedes in discovering what composed the kings crown.

The various factors that impact the solubility of substances in water are - nature of solute and solvent, temperature, pressure and pH.

The solubility of substances in water is influenced by several factors:

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Answer:

BF3

Explanation:

The octet rule describes atoms' preference and affinity for having eight (8) electrons in their valence shell. Whenever an atom is encircled by eight(8) electrons, it forms a stable configuration. This octet can be composed of its' own electrons as well as some shared electrons. In the periodic table, only the s-block and p-block electrons are considered for the octet rule.

However, out of the given option, only BF3 does not comply with the octet rule: This is because the Bromine contains 2 lone pairs of electrons and 3 other shared bonded pairs of electrons with Flourine making a total of 10 electrons in the valence shell and which does not conform with the octet rule.

it depends on the widths of the recesses, and if it is causing the shelf to fracture and collapse into the sea, then a massive iceberg could be called from the life she,f and the ice shelf are way more important because it holds it up

Answer:

both

Explanation:

A homolytic fission is said to have occurred when the breakage of a bond between two atoms leaves each of the bonding atoms with equal number of electrons. Homolytic fission often results in the creation of radicals.

Since homolytic fission yields two species with equal number of electrons(usually odd number of electrons), the products of such process can not be charged. They can not be nucleophiles because nucleophiles need to possess two electrons which can be shared with another chemical specie.

Answer:

E°(Ag⁺/Fe°) = 0.836 volt

Explanation:

3Ag⁺ + 3e⁻ => Ag°;            E° = +0.800 volt

Fe° => Fe⁺³ + 3e⁻ ;             E° = -0.036 volt

_________________________________

Fe°(s) + 3Ag⁺(aq) => Fe⁺³(aq) + 3Ag°(s) ...    

E°(Ag⁺/Fe°) = E°(Ag⁺) - E°(Fe°) = 0.800v - ( -0.036v) = 0.836 volt

Answer:

Lower than

Higher than

Explanation:

The vapour pressure and boiling point of liquids are inversely related. Thus, the higher the vapour pressure of a liquid, the lower it's boiling point. Lower vapour pressure implies that the liquid is easily converted into vapour phase.

If hexane has a higher vapour pressure than water then its boiling point is lower than that of water and its vapor pressure when it is boiling will be higher than water when water is boiling.

Answer:

HCN, weak acid

H⁺, Br⁻, strong acid

Explanation:

Hydrocyanic acid is a weak acid, according to the following equation.

HCN(aq) ⇄ H⁺(aq) + CN⁻(aq)

Thus, it should be written in the undissociated form (HCN).

Hydrobromic acid is a strong acid, according to the following equation.

HBr(aq) ⇒ H⁺(aq) + Br⁻(aq)

Thus, it should be written in the ionic form (H⁺, Br⁻).

Answer:

–0.09

Explanation:

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

Measured value = 5.88 g

Actual value = 5.97 g

Error =?

The error in the student's measurement can be obtained as follow:

Error = Measured value – Actual value

Error = 5.88 – 5.97

Error = –0.09

Therefore, the error in the student's measurement is –0.09

Answer:

d.

Explanation:

H2 + Cl2 = 2HCL

From the equation 2g hydrogen combine with 71g of chlorine.

So 35.5 g Cl2 combines with 1g of H2

There are 100g of Cl2 so this will, by proportion, react with 100/35.5 g hydrogen.

This is 2.8 g hydrogen so the mass of HCl formed = 102.8 g.

The true statement is that d. between 100 and 190 g of HCl is produced.

To find mass of HCL:

H2 + Cl2 = 2HCL

From the equation, 2g of hydrogen combines with 71g of chlorine.

So 35.5 g Cl2 combines with 1g of H2

There are 100g of Cl2 so this will, by proportion, react with 100/35.5 g of hydrogen.

This is 2.8 g hydrogen so the mass of HCl formed = 102.8 g.

Hydrogen chloride may be formed by the direct combination of chlorine (Cl2) gas and hydrogen (H2) gas.

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Answer:

Draw the skeletal structure for: (E)-hept-5-en-2-one

Explanation:

The root word hept indicates that the given compound has seven carons in its longest chain.

-en- primary suffix indicates that the compound has one double bond in it.

2-one indicates that the compound has -C=O bond in the second carbon.

The prefix (E) indicates that the highest priority groups are on the opposite direction of the double bond.

The structure of the given molecule is:

Answer:

Explanation:

hope it heloed

The question is incomplete, the complete question is:

A chemist measures the amount of iodine solid produced during an experiment. He finds that 8.31 g of iodine solid is produced. Calculate the number of moles of iodine solid produced. Round your answer to the correct number of significant digits.

Answer: The number of moles of solid iodine produced is 0.0327 moles

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of solid iodine = 8.31 g

Molar mass of solid iodine = 253.8089 g/mol

Plugging values in equation 1:

[tex]\text{Moles of solid iodine}=\frac{8.31g}{253.8089g/mol}=0.0327mol[/tex]

Hence, the number of moles of solid iodine produced is 0.0327 moles

Answer:

1.17 L of H₂

Explanation:

We'll begin by calculating the number of mole in 2.3 g of Mg. This can be obtained as follow:

Mass of Mg = 2.3 g

Molar mass of Mg = 24 g/mol

Mole of Mg =?

Mole = mass /molar mass

Mole of Mg = 2.3 / 24

Mole of Mg = 0.096 mole

Next, we shall determine the number of mole of H₂ produced by the reaction of 2.3 g (i.e 0.096 mole) of Mg. This can be obtained as follow:

Mg + 2HCl —> MgCl₂ + H₂

From the balanced equation above,

1 mole of Mg reacted to 1 mole of H₂.

Therefore, 0.096 mole of Mg will also react to produce 0.096 mole of H₂.

Finally, we shall determine volume of H₂ produced from the reaction. This can be obtained as follow:

Number of mole (n) of H₂ = 0.096 mole

Pressure (P) = 2 atm

Temperature (T) = 298 K

Gas constant (R) = 0.0821 atm.L/Kmol

Volume (V) of H₂ =?

PV = nRT

2 × V = 0.096 × 0.0821 × 298

Divide both side by 2

V = (0.096 × 0.0821 × 298) /2

V = 1.17 L

Therefore, 1.17 L of H₂ were obtained from the reaction.

Answer:

1 ) Δs ( entropy change for hot block ) = - Q / th  ( -ve shows heat lost to cold block )

Δs ( entropy change for cold block ) = Q / tc

∴ Total Δs = ΔSc + ΔSh

                 = Q/tc - Q/th

2) ΔSdecomposition = Δh / Temp = ( 181.6 * 10^3 / 773 ) = 234.928 J/k

Explanation:

1) To show that heat flows spontaneously from high temperature to low temperature

example :

Pick two(2) solid metal blocks with varying temperatures ( i.e. one solid block is hot and the other solid block is cold )

Place both blocks for time (t ) in an insulated system to reduce heat loss or gain to or from the environment

Check the temperature of both blocks after time ( t ) it will be observed that both blocks will have same temperature after time t ( first law of thermodynamics )

Δs ( entropy change for hot block ) = - Q / th  ( -ve shows heat lost to cold block )

Δs ( entropy change for cold block ) = Q / tc

∴ Total Δs = ΔSc + ΔSh

                 = Q/tc - Q/th

2) Entropy change for Decomposition of mercuric oxide

2HgO (s) → 2Hg(l) + O₂ (g)

Δs = positive

there is transition from solid to liquid and the melting point of mercury ( the point at which reaction will take place ) = 500⁰C

hence ΔSdecomposition = S⁻ Hg  -  S⁻ HgO =

Δh of reaction = 181.6 KJ

Temp = 500 + 273 = 773 k

hence ΔSdecomposition = Δh / Temp = ( 181.6 * 10^3 / 773 ) = 234.928 J/k

Answer:

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1) The order of decreasing priority would allow determining E/Z or R/S is "dbca".

2)  The order of decreasing priority would allow determining E/Z or R/S is "acbd".

Absolute configuration can be described as to the spatial arrangement of atoms within a chiral molecular entity. Absolute configuration in organic molecules, where carbon is bonded to four different substituents.

The absolute configuration has used a set of rules to describe the relative positions around the chiral center atom. The most common labeling method is the descriptors R or S where R and S refer to Rectus and Sinister.

The group with the highest atomic number will get the highest priority and the group with the lowest atomic number substituents will get the lowest priority. Therefore, the order of priority is -CH₂Br > -CH₂OH > -CH₂NH₂ > -CH₃.

Therefore, the order of priority for the second part is -F > -CHO > -CH₂OH > -CH₃.

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Answer:

For (1): The correct option is (a)

For (2): The correct option is (a) and 333.6 kJ of heat will be absorbed when 70.9 g of ammonia reacts.

Explanation:

There are 2 types of reactions that are classified based on enthalpy change:

Endothermic reactions: These are the reactions where heat is absorbed by the reaction. The change in enthalpy of the reaction, [tex]\Delta H_{rxn}[/tex] is positive for these reactions.

Exothermic reactions: These are the reactions where heat is released by the reaction. The change in enthalpy of the reaction, [tex]\Delta H_{rxn}[/tex] is negative for these reactions.

For the given chemical reaction:

[tex]2NH_3(g)\rightarrow N_2(g)+3H_2(g);Delta H=160kJ[/tex]

As the change in enthalpy or heat of the reaction is positive. Thus, the reaction is an endothermic reaction because heat is absorbed by the reaction.

When ammonia reacts, some amount of heat will be absorbed by the reaction. Thus, we can say the heat will be absorbed.

The number of moles is calculated by using the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of ammonia = 70.9 g

Molar mass of ammonia = 17 g/mol

Using equation 1:

[tex]\text{Moles of ammonia}=\frac{70.9g}{17g/mol}=4.17mol[/tex]

By stoichiometry of the reaction:

If 2 mole of ammonia reacts, the heat absorbed is 160 kJ

So, if 4.17 moles of ammonia reacts, the heat absorbed will be = [tex]\frac{160kJ}{2mol}\times 4.17mol=333.6kJ[/tex]

Hence, 333.6 kJ of heat will be absorbed when 70.9 g of ammonia reacts

Answer:

6.023*10^23........ .......

Answer:

Mg3N2

Explanation:

it would be magnesium as it would loss to electron so it would have 10 electron. you can see in the picture above .

hope this helps :)

Answer:

Explanation:

From the given reaction:

[tex]6Cl_{2(g)}+2Fe_2O_{3(s)} \to 4FeCl_{3(s)}+3O_2[/tex]

From the Gibbs Free Energy table at standard conditions, the value of each compound is as follows:

[tex]G_f^0 \ of \ Cl_2 = 0 \ KJ/mol[/tex]                       [tex]G_f^0 \ of \ Fe_2O_3 = -742.24 \ KJ/mol[/tex]

[tex]G_f^0 \ of \ Fe_2Cl_3 = -334.05 \ KJ/mol[/tex]      [tex]G_f^0 \ of \ O_2 = 0 \ KJ/mol[/tex]

Now, the standard Gibb's Free energy for the given reaction can be estimated as follows:

[tex]\mathtt{\Delta G^0 = (4 *G_f^0(FeCl_3) +3*G_f^0(O_2)) - (6*G_f^0 (Cl_2) +2*G_f^0(Fe_2O_3))}[/tex]

[tex]\mathtt{\Delta G^0 = (4 *(-334.05) +3*(0)) - (6(0) +2(-742.24))}[/tex]

[tex]\mathtt{\Delta G^0 = 148.28 \ kJ/mol}[/tex]

using the following formula:

[tex]\mathtt{\Delta G^0 =-RTIn K_{eq}}[/tex]

the equilibrium constant can  be determined as:

[tex]\mathtt{ In K_{eq} =\dfrac{\Delta G^0 }{-RT}}[/tex]

[tex]\mathtt{ In K_{eq} =\dfrac{148.28*10^3 J/mol }{-(8.314 \ J/k mol )*298 \ K}}[/tex]

[tex]\mathtt{ In K_{eq} =-59.85}[/tex]

[tex]\mathtt{ K_{eq} =e^{-59.85}}[/tex]

[tex]\mathtt{ K_{eq} =1.0*10^{-26}}[/tex] to 2 significant figures.

Answer: A bromine radical is more stable than chlorine radical, so it is less reactive and more choosy.

Explanation:

A chlorine atom being more electronegative in nature is able to attract a hydrogen atom more readily towards itself as compared to a bromine atom.

Since bromine is less electronegative in nature so bromine will be more selective as a hydrogen abstracting agent. As a result, bromine radical is more stable in nature than chlorine radical.

Thus, we can conclude that bromine radical is more stable than chlorine radical, so it is less reactive and more choosy.

Answer:

Higher than the actual value

Explanation:

Titration is a volumetric process in which a known volume of solution is dispensed from a burette to react with a known volume of solution in a conical flask.

When acid-base titration is carried out in such a way that the base is in the burette and the acid is in the conical flask and drops of the base adhere to the inner walls of the flask, but do not actually mix with the solution, the calculated acid concentration would be higher than the actual value.

This is because;

From CA= CBVBnA/VAnB

When VB(volume of base) that reacted is lower than the actual volume recorded, then the calculated volume of CA(concentration of acid) is much higher than the actual value since drops of the base adhere to the inner walls of the flask.

Answer:

2.89x10⁻⁵M = [HPO₄²⁻]

Explanation:

The equilibrium of H3PO4 in water occurs H2PO4-:

H3PO4(aq) + H2O(l) ⇄ H3O⁺(aq) + H2PO4⁻(aq)

pKa = 2.16. And as pKa = -log Ka; Ka = 10^-2.16

Ka = 6.9183x10⁻³ = [H3O⁺] [H2PO4⁻] / [H3PO4]

As both [H3O⁺] and [H2PO4⁻] comes from the same equilibrium,

[H3O⁺]=[H2PO4⁻] :

[H3O⁺] = X

[H2PO4⁻] = X

[H3PO4] = 0.042 - X

Where X is reaction coordinate

Replacing:

6.9183x10⁻³ = [X] [X] / [0.042 - X]

6.9183x10⁻³ = X² / 0.042 - X

2.905686x10⁻⁴ - 6.9183x10⁻³X - X² = 0

Solving for X:

X = -0.02M. False solution. There is no negative concentration.

X = 0.014M. Right solution

[H2PO4⁻] = 0.014M

In the second equilibrium:

H2PO4⁻(aq) + H2O(l) ⇄ HPO4-(aq) + H3O+(aq)

Based on the same principles of the last equilibrium:

pKa2 = 7.21

Ka2 = 6.166x10⁻⁸ = [HPO4-] [H3O+] / [H2PO4⁻]

[HPO4-] = X

[H3O+] = X

[H2PO4⁻] = 0.014M - X

6.166x10⁻⁸ = X² / [0.014M - X]

8.3623x10⁻¹⁰ - 6.166x10⁻⁸X - X² = 0

Solving for X:

X = -0.0000289485. False solution.

X =

Answer:

The answer is Iron.

Explanation:

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Answer:

oshfjidgshsjdh

Explanation:

918474828

Answer:

43.0 L

Explanation:

Step 1: Given and required data

Step 2: Calculate the volume of the flask (V)

We will use the ideal gas equation.

P × V = n × R × T

V = n × R × T / P

V = 1.99 mol × (0.0821 atm.L/mol.K) × 313 K / 1.19 atm = 43.0 L

The answer is 4.30 L

The electronegativity increases across the period and decreases down the group. Thus, option B is correct.

Electronegativity can be defined as the tendency of an atom to gain or attract an electron. The electronegativity has been dependent on the size of the atom, as well as the atomic number and valence electrons.

The atom with the requirement of a less number of atoms to complete its octet can easily gain the electron and thereby have high electronegativity. The atomic size also plays a role in the electronegativity of the atom.

The atom with a bigger size has the lesser force of attraction from the nucleus and thus has difficulty attracting the electron, however, the smaller size atom can easily attract the electron with the attraction force from the nucleus.

Thus, the elements with smaller sizes and a high number of valence electrons are more electronegative. In the periodic table, on moving from left to right the valence electrons increase, thus the electronegativity increases.

On moving down the group, the element size increase, thus the electronegativity decreases down the group.

The electronegativity increases across the period and decreases down the group. Thus, option B is correct.

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