27. Which of the following elements has the greatest electron affinity?
beryllium
b. neon
C fluorine
d. iridium

A student asked about the amount of nickel plated out of a Ni(NO3)2 solution when a current of 5.41 A is passed through it for 1.90 hours.

To determine this, we can use Faraday's laws of electrolysis.

First, we need to find the charge passed through the solution. Charge (Q) can be calculated using the formula Q = I × t, where I is the current and t is the time in seconds. Since 1 hour is equal to 3600 seconds, 1.90 hours is equal to 1.90 × 3600 = 6840 seconds.

Now we can calculate the charge: Q = 5.41 A × 6840 s = 36996 Coulombs.

Next, we need to determine the amount of nickel deposited. The relationship between charge and moles of substance can be described using Faraday's constant (F), which is approximately 96485 Coulombs/mol of electrons. The balanced half-reaction for the reduction of Ni(II) ions is:

Ni(II) + 2e- → Ni(s)

Thus, 2 moles of electrons are needed to deposit 1 mole of nickel. Now we can calculate the moles of nickel

Moles of Ni = (Q × (1 mole Ni / (2 moles e-))) / F = (36996 C × (1 mole Ni / (2 moles e-))) / 96485 C/mol = 0.1918 moles Ni.

Finally, we need to convert moles of nickel to grams. The molar mass of nickel is 58.69 g/mol. So, the mass of nickel deposited is

Mass of Ni = moles of Ni × molar mass = 0.1918 moles × 58.69 g/mol = 11.26 grams.

Therefore, 11.26 grams of nickel is plated out of the Ni(NO3)2 solution when a 5.41 A current is passed through it for 1.90 hours.

Know more about Faraday's laws here:

https://brainly.com/question/17012638

#SPJ11      

The D-Aldo triose is a type of sugar molecule that belongs to the family of trioses, which are three-carbon sugars. There are two possible stereoisomers of Aldo triose: D-Aldo triose and L-Aldo triose. D-Aldo triose has all three hydroxyl groups (-OH) on the same side of the carbon chain, while L-Aldo triose has them on alternating sides.

To check all D-Aldo triose, we need to consider the stereochemistry of each possible Aldo triose molecule. There are two D-Aldo triose isomers: D-glyceraldehyde and D-erythrose. D-glyceraldehyde has a -CHO group (aldehyde group) at one end of the carbon chain and a -CH2OH group (hydroxymethyl group) at the other end. The remaining carbon has a -OH group attached. This gives D-glyceraldehyde the chemical formula C3H6O3. D-erythrose has two -OH groups and one -CHO group, with the -CHO group at one end of the carbon chain and the two -OH groups at the other end. This gives D-erythrose the chemical formula C4H8O4. Therefore, to check all D-aldotriose, we need to examine the chemical structures of D-glyceraldehyde and D-erythrose and verify that they meet the criteria for being D-aldotriose isomers. Once we have confirmed their stereochemistry, we can conclude that these are the only two D-Aldo triose isomers that exist.

learn more about molecule here.

https://brainly.com/question/19556990

#SPJ11

Answer:

This is called combination reaction

A chemist can identify an oxidation-reduction reaction by analyzing whether or not there has been a change in the oxidation number of the reactants. This is done by examining how the reaction affects the movement of electrons between the different molecules involved.

Oxidation is the process by which a molecule loses electrons, while reduction is the process by which a molecule gains electrons. An oxidation-reduction reaction is a reaction that involves the transfer of electrons from one molecule to another. This can be identified by analyzing the change in the oxidation numbers of the different molecules involved.

For example, in the reaction between hydrogen and chlorine, H₂ + Cl₂ → 2HCl, hydrogen is oxidized from an oxidation state of 0 to +1, while chlorine is reduced from an oxidation state of 0 to -1. This indicates that this is an oxidation-reduction reaction.

Learn more about oxidation-reduction reaction here: https://brainly.com/question/4222605

#SPJ11

Answer: 4P + 3O2 → P4O6

Explanation: plz give brainliest

Answer:

nNaOH = 0,2 mol

Trong hỗn hợp các chất đề bài cho chỉ có phenol tác dụng với NaOH

C6H5OH + NaOH → C6H5ONa + H2O

   0,2  ←     0,2 (mol)

⟹ mphenol = 0,2.94 = 18,8 gam

⟹  

%mC6H5OH=18,8/28,9 x100%= 65,05%

Explanation:

Answer:

The capital A answer

Explanation:

Carbon has an atomic number of 12 not 14

It does not necessarily indicate that the two compounds are different from each other.

a. False. An impurity does not always lower the melting point of an organic compound. In some cases, impurities can raise the melting point of a substance. The effect of an impurity on the melting point depends on the specific interactions between the impurity and the compound. Impurities can disrupt the crystal lattice structure of the compound, which can either hinder or facilitate the melting process.

b. False. While a sharp melting point is typically associated with a pure single compound, it does not guarantee it. A sharp melting point indicates that the substance undergoes a phase transition over a narrow temperature range. However, it is possible for mixtures of compounds to exhibit sharp melting points if the components have similar melting points and form eutectic mixtures. Therefore, a sharp melting point does not necessarily imply purity.

c. False. The lack of a decrease in the melting point of compound X upon addition of compound A does not necessarily mean that X is identical to A. It is possible that compound A and X do not form a solid solution or do not have a significant impact on each other's melting points. The melting point depression depends on the solubility of A in X and the extent of the molecular interactions between the two compounds.

d. False. The lowering of the melting point of compound X upon addition of compound A does not exclude the possibility that X and A are identical. The depression of the melting point can occur due to the formation of a solid solution between X and A or due to a decrease in the overall crystallinity of X. It does not necessarily indicate that the two compounds are different from each other.

To learn more about compounds visit;

https://brainly.com/question/14117795

#SPJ11

The volume of the air bubble that will form if the pressure outside the submarine breaks it will be approximately 13.95 liters.

What is the volume?

Assuming that the temperature remains constant, we can use Boyle's law to determine the volume of the air bubble that will form if the pressure outside the submarine breaks it. Boyle's law states that the pressure of a gas is inversely proportional to its volume when temperature is held constant.

Let V1 be the initial volume of the air in the submarine, P1 be the initial pressure inside the submarine (1.01 atm), P2 be the pressure outside the submarine (1086 atm), and V2 be the final volume of the air bubble.

According to Boyle's law, we have:

P1 x V1 = P2 x V2

Substituting the given values, we get:

1.01 atm x 15,000 L = 1086 atm x V2

Solving for V2, we get:

V2 = (1.01 atm x 15,000 L) / 1086 atm = 13.95 L

Therefore, the volume of the air bubble that will form if the pressure outside the submarine breaks it will be approximately 13.95 liters.

To know more about volume, visit:

https://brainly.com/question/11066220

#SPJ1

Complete question is: Submarines need to be extremely strong to withstand the extremely high pressure of water pushing down on them. An experimental research submarine with a volume of 15,000 liters has an internal pressure of 1.01 atm. If the pressure of the ocean breaks the submarine, 13.95 liters the bubble of air in the submarine be if the pressure outside the sub is 1086 atm.

If the unknown solution tested positive in both test 44 and test #7, it indicates a potential error in the experiment. Test 44 and test #7 are designed to detect different properties or components of the solution.

A positive result in both tests suggests a discrepancy or inconsistency in the results, which may be due to contamination, experimental errors, or improper technique.

While a positive result in both tests indicates a problem with the experimental procedure, it does not provide clear information about the nature or identity of the unknown solution. It could be a false positive due to an experimental error or a genuine indication of the presence of certain components. Further investigation and additional tests may be required to determine the true nature of the solution.

On the other hand, if the unknown solution tested negative in both test 44 and test #7, it suggests that the solution does not possess the expected properties or components that the tests were designed to detect. This result could indicate that the solution does not contain certain substances or is not consistent with the expected composition.

In terms of the impact of these outcomes, it would depend on the specific context and objectives of the experiment. However, generally speaking, if the unknown solution tested positive in both tests, it raises concerns about the reliability and accuracy of the experimental procedure. It highlights the need for further investigation and analysis to determine the true nature of the solution. Conversely, if the unknown solution tested negative in both tests, it provides clearer information regarding the absence of expected components or properties, although additional tests may still be required to draw definitive conclusions.

Overall, the scenario where the unknown solution tests positive in both tests is generally considered worse because it introduces more uncertainty and questions the reliability of the experimental results.

learn more about solution here

https://brainly.com/question/1616939

#SPJ11

Answer:

Q = 143,921 J = 143.9 kJ.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the absorbed heat by considering this is a process involving sensible heat associated to the vaporization of water, which is isothermic and isobaric; and thus, the heat of vaporization of water, with a value of about 2259.36 J/g, is used as shown below:

\(Q=m*\Delta _{vap}H\)

Thus, we plug in the mass and the aforementioned heat of vaporization of water to obtain the following:

\(Q=63.7g*2259.36J/g\\\\Q=143,921J=143.9kJ\)

Regards!

Answer:

neon

Explanation:

it comes in different colours

The temperature needed for 41 grams of O₂ to expand to a volume of 2L under a pressure of 1 atm is approximately 19.023 Kelvin.

We know that the ideal gas equation is:

PV = nRT ......(i)

where P ⇒ pressure

V ⇒ volume of the gas

n ⇒ number of moles of the gas

T ⇒ temperature in Kelvin

R ⇒ ideal gas constant = 0.082057 (L·atm/(mol·K))

Now, as per the question:

Mass of O₂ = 41 grams

The volume of expanded gas, V = 2 L

Pressure, P = 1 atm

We need to determine the temperature needed for the gas to expand to 2 L.

For that, we need to calculate the number of moles of O₂ gas first.

Since,

no. of moles = mass of the gas / molar mass of the gas

(∵ molar mass of O₂ = 32 g)

moles = 41 g / 32 g/mol

moles ≈ 1.28125 mol

Now,  to solve for temperature (T),

The ideal gas equation can be written as:

\(T=\frac{PV}{nR}\)  ......(ii)

Now, substituting the given values in the equation (ii):

\(T = \frac{(1)*(2)}{(1.28125)*(0.082057)} \frac{(atm).(L)}{(mole).(L.atm/mol.K)}\)

\(T = \frac{2}{0.105136} \frac{atm.L}{(L.atm)/K}\)

T ≈ 19.023 K

Thus, the temperature needed for 41 grams of O₂ to expand to a volume of 2 L under a pressure of 1 atm is approximately 19.023 Kelvin.

Click here to learn more about ideal gas law:

brainly.com/question/27009857

The balloon must be cooled to 39.69°C to reduce its volume to 3.96 l (at constant pressure).

According to Charles's law when the amount of gas and pressure are kept constant, the quotient that exist between the volume and the temperature will always have the same value.

                                 \(\frac{V}{T}=k\)

Comparing an initial state 1 and a final state, it satisfied

                                 \(\frac{V_{1} }{T_{1} } =\frac{V_{2} }{T_{2} }\)

Given information:

Initial volume:          \(V_{1} =4.39l\)

Initial temperature: \(T_{1}=44\) °C

Final volume:          \(V_{2} =3.96l\)

Final temperature: \(T_{2}=?\)

By applying Charles's law, we can find at which temperature the balloon must cooled to reduce its volume to 3.96L.

                               \(\frac{V_{1} }{T_{1} }=\frac{V_{2} }{T_{2} }\)

                              \(\frac{4.39}{44}=\frac{3.96}{T_{2} }\)

                              \(T_{2}=39.69\)°С

Hence, the balloon must cool to 39.69°C to reduce its volume to 3.96L.

Learn more about Charles's law visit:

brainly.com/question/3491421

#SPJ4

The balloon must be cooled to 39.69°C to reduce its volume to 3.96 l (at constant pressure).

According to Charles's law when the amount of gas and pressure are kept constant, the quotient that exist between the volume and the temperature will always have the same value.

                        \(\frac{V}{T}=K\)

Comparing an initial state 1 and a final state, it satisfied

                      \(\frac{V_{1} }{T_{1} } =\frac{V_{2} }{T_{2} }\)

Given information:

Initial volume: \(V_{1} =4.38l\)        

Initial temperature: \(T_{1} =44\)°C

Final volume:  \(V_{2}=3.96l\)        

Final temperature: \(T_{2} =?\)

By applying Charles's law, we can find at which temperature the balloon must cooled to reduce its volume to 3.96L.

                              \(\frac{V_{1} }{t_{1} } =\frac{V_{2} }{T_{2} }\)

                              \(\frac{4.39}{44} =\frac{3.96}{T_{2} }\)

                               \(T_{2} =39.69\)°С

Hence, the balloon must cool to 39.69°C to reduce its volume to 3.96L.

Learn more about Charles's law visit:

brainly.com/question/3491421

#SPJ4

Explanation:

The balanced equation is 2SO2+O2→2SO3

Answer:

25.56066

Explanation:

hope this helps !!!!!!! and sorry if it doesn't help

Answer: From top to bottom, 1 3 4 5 6

Explanation: The empirical formula is the most reduced whole number ratio of elements. N2O4 is the only compound that can be further reduced, making the empirical formula NO2, and thus is different from the molecular formula.

According to thermal energy,the change in energy ΔE is equal to 17 kJ of heat.

Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.

Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.

ΔE=20.8-3.8=17 kJ

Thus, the change in energy ΔE is equal to 17 kJ of heat.

Learn more about thermal energy,here:

https://brainly.com/question/3022807

#SPJ1

Answer:

Sure, with what?

Ps- Just to increase word count

Time taken for the partial pressure of that gas to drop to 0.25atm is 60.

What is half-life of 1st order reaction?

A reaction's half-life is the amount of time needed for the reactant concentration to drop to half its initial value.

Rate constant value

t1/2 = 0.693/k

     k= 0.693÷20

        =0.03465

ln {0.25} ÷2= -0.0346 t

t=60

To learn more about half-life of 1st order reaction

https://brainly.com/question/13043571

#SPJ4

To confirm the presence of \(\(Pb^2^+\)\) ions, the substance that can be used is potassium thiocyanate (KSCN). Therefore, the correct answer is: e. Potassium thiocyanate

When potassium thiocyanate is added to a solution containing \(Pb^2^+\) ions, it forms a reddish-brown precipitate called lead(II) thiocyanate \((Pb(SCN)^2)\). This reaction is a common test for the presence of \(Pb^2^+\) ions.

The reaction can be represented by the following equation:

\(Pb^2^+\) (aq) + 2 \(SCN^-[/tex} (aq) → \(Pb(SCN)^2\) (s)

In this reaction, the Pb2+ ions from the solution react with the thiocyanate ions (SCN-) to form a reddish-brown precipitate of lead(II) thiocyanate. The formation of the precipitate confirms the presence of \(Pb^2^+\) ions in the solution.

To know more about Potassium Thiocyantae:

https://brainly.com/question/28300500

#SPJ11

Answer:

People with a nasal voice can sound as though they're speaking through a clogged-up or runny nose, which are both possible causes. Your speaking voice is created when air leaves your lungs and flows upward through your vocal cords and throat into your mouth. The resulting sound quality is called resonance. (i hope i helped ya )

Explanation:

The p-value is greater than the significance level of 0.05, we do not reject the null hypothesis and conclude that all proportions are equal.

Firstly, let us conduct a Chi-square test of independence of categorical variables based on the information given above. We have three different cases of hypothesis testing that we have to solve one by one.

Case 1: HD​:pSun ​=rhoMan ​=pTue ​=pWed ​=pThu ​=pFri ​=pSat ​=71​
Ha​ : Not all proportions are equal.

Test Statistic
For this hypothesis, we need to compute the test statistic that is given as:
\($$\chi^2=\sum_{i=1}^{k}\frac{(O_i-E_i)^2}{E_i}$$\)  where k is the number of groups/categories. Since we have 7 days of the week, \(k = 7. $O_i$ and $E_i$\) are the observed and expected frequencies respectively.  
Here, we have equal proportions of 71 for each day of the week.
Therefore, the expected frequencies are also equal to 71.
\($$E_i = 71, i=1,2,3,4,5,6,7.$$\)

We also have to use the given information to compute the observed frequencies,
\($O_i$.$$O_1 = 90, O_2 = 99, O_3 = 122, O_4 = 123, O_5 = 130, O_6 = 160, O_7 = 126$$\)

Therefore, the test statistic can be computed as \($$\chi^2=\frac{(90-71)^2}{71} + \frac{(99-71)^2}{71} + \frac{(122-71)^2}{71} + \frac{(123-71)^2}{71} + \frac{(130-71)^2}{71} + \frac{(160-71)^2}{71} + \frac{(126-71)^2}{71}$$$$\chi^2=180.14\)

Now we have to find the p-value of this test. Since the number of degrees of freedom is k - 1 = 7 - 1 = 6, the p-value can be found using the chi-square distribution table with 6 degrees of freedom at the 0.05 significance level. The p-value is 0.000014. ConclusionSince the p-value is less than the significance level of 0.05, we reject the null hypothesis and conclude that not all proportions are equal.

The total number of accidents is \($$90+99+122+123+130+160+126=850$$\)

The percentage of accidents occurring on each day of the week can be found as follows:
\($$Sunday: $$\frac{90}{850}\times 100 = 10.59\%$$Monday: $$\frac{99}{850}\times 100 = 11.65\%$$Tuesday: $$\frac{122}{850}\times 100 = 14.35\%$$Wednesday: $$\frac{123}{850}\times 100 = 14.47\%$$Thursday: $$\frac{130}{850}\times 100 = 15.29\%$$Friday: $$\frac{160}{850}\times 100 = 18.82\%$$Saturday: $$\frac{126}{850}\times 100 = 14.82\%$$\)

From the above percentages, we can see that Friday has the highest percentage of traffic accidents.

Case 2:
HD​: Not all proportions are equal.

Ha​:pSun ​=pMon ​=pTue ​=rhoWed ​=pThu ​=rhoFri ​=rhoSat ​=71

Test Statistic

\($$E_1 = 78.57, E_2 = 86.57, E_3 = 106.86, E_4 = 107.43, E_5 = 113.57, E_6 = 139.43, E_7 = 109.14$$\)

We already know the observed frequencies,
\($$O_1 = 90, O_2 = 99, O_3 = 122, O_4 = 123, O_5 = 130, O_6 = 160, O_7 = 126.$$\)

The test statistic can be computed as:

\($$\chi^2=\frac{(90-78.57)^2}{78.57} + \frac{(99-86.57)^2}{86.57} + \frac{(122-106.86)^2}{106.86}+ \frac{(123-107.43)^2}{107.43} + \frac{(130-113.57)^2}{113.57} + \frac{(160-139.43)^2}{139.43} + \frac{(126-109.14)^2}{109.14} $$$$ \implies \chi^2=34.98$$\)
The p-value is 0.000001.
Conclusion- Since the p-value is less than the significance level of 0.05, we reject the null hypothesis and conclude that not all proportions are equal.

Case 3:

All proportions are equal.
Test Statistic
The expected frequency for each group is
\(E = \frac{850}{7} = 121.43\)
We already know the observed frequencies,
\($$O_1 = 90, O_2 = 99, O_3 = 122, O_4 = 123, O_5 = 130, O_6 = 160, O_7 = 126.$$\)

The test statistic is,

\($$\chi^2=\frac{(90-121.43)^2}{121.43} + \frac{(99-121.43)^2}{121.43} + \frac{(122-121.43)^2}{121.43} + \frac{(123-121.43)^2}{121.43} + \frac{(130-121.43)^2}{121.43} + \frac{(160-121.43)^2}{121.43} + \frac{(126-121.43)^2}{121.43}} \\\implies \chi^2=9.17$$\)

The p-value is 0.1664.

Since the p-value is greater than the significance level of 0.05, we do not reject the null hypothesis and conclude that all proportions are equal.

To know more about p-value visit:

https://brainly.com/question/30761573

#SPJ11

Answer:

The correct answer is - option 1. the solution is acidic.

Explanation:

The pH is a scale to measure or check the acidity or basicity of an aqueous solution. The lower values on the pH scale indicate the acidity of the solution as on the pH bar 0 indicating the highest acidic value and the higher value indicates the alkaline or basic value of the solution and 14 indicating the highest alkaline. The pH of water is 7 which is a neutral condition.

Therefore, the pH of a solution with 5.5 on pH solution represents the acidic property of the solution, however, it is slightly acidic as it is near the neutral value.

Answer:

The solution is acidic

Explanation:

The lower the number, the more acidic the solution is

Intraspecific competition has a beneficial affect due to factors such as predators, disease and overpopulation. Thus option A is correct since all the above are beneficial factors.

Competition is described as an interaction between two or more individuals from the same or two or more populations wherein one negatively impacts the other in access to a limited resource (or resources) (food, water, nesting places, shelter, mates, etc.). Intraspecific competition occurs when individuals from the same species (cospecifics) compete. The impact of competition on each individual within the species is determined by the sort of competition that occurs.  When a species competes for a finite resource, all individuals eat equal quantities until the supply is gone, all members of that population may die of starvation.  On the other hand, when one individual competes and wins over a resource, and that resource is exploited, it continues to exist.

Learn more about intraspecific competition here:

https://brainly.com/question/31066889

#SPJ1

Answer:

[(x-37.5)/x]*100%

62.5%  (assuming the original sample weighs 100.0g)

Explanation:

Let's say that the original sample is x

Mass of I-125 which has decayed: x-37.5

Percentage of decayed mass: [(x-37.5)/x]*100%

Please recheck, for this may not be the correct answer

In order for a titration to be effective, the reaction must produce a precipitate. The correct answer is option B, "reaction must produce a precipitate."

For a titration to be effective, the reaction must be stoichiometric, quantitative, and rapid. A stoichiometric reaction is one in which the amount of reactants is proportional to the amount of products.

A quantitative reaction is one in which all the reactants are consumed, leaving no excess. A rapid reaction is one that occurs quickly and does not take a long time to complete.

However, a reaction producing a precipitate is not necessary for the titration to be effective. Hence option B is correct.

Learn more about titration here:

brainly.com/question/2728613

#SPJ11