A student carries out a flame test on an unknown solid. a red flame is seen. the student concludes that the solid is lithium carbonate. explain why this conclusion is not justified​

Answer:

26.5°C

Explanation:

We can solve this question using the equation:

q = m*S*ΔT

Where Q is heat gained in joules, m is the mass of the sample, S is specific heat and ΔT change in temperature.

With the sample A we can find specific heat of cobalt in order to find, in sample B, the ΔT and the final temperature:

Sample A:

q = m*S*ΔT

6.70J = 5.00g*S*(27.9°C-25.0°C)

0.462J/g°C = Specific heat of cobalt

Sample B:

q = m*S*ΔT

5.00J = 7.00g*0.462J/g°C*ΔT

1.5°C = ΔT

As the initial temperature of sample B is 25°C, final temperature is:

25°C + 1.5°C = 26.5°C

Answer:

See explanation

Explanation:

The electrophilic substitution of aromatic compounds occurs faster in substituted aromatic compounds due to the fact that the ring becomes more or less susceptible to electrophilic attack depending on the nature of the substituent in the ring.

Electron pushing substituents such as alkyl groups stabilize the positive charge developed during electrophilic substitution hence they activate the ring towards electrophilic substitution.

The methyl group is an ortho - para directing substituent hence the product obtained by nitration of toluene is o-nitrotoluene and p-nitrotoluene.

The stepwise mechanism for obtaining these products is shown in the image attached to this answer.

Answer:

Chirality is a particularly important concept in biology, because cells are mostly composed of chiral molecules. Small chiral molecules such as amino acids and sugars (figure 1, top) are the building blocks of larger molecules, such as proteins and nucleic acids, which are also chiral

Answer:

Option B, Dynamic force

Explanation:

Cloudy water is an abiotic factor as it cannot support life and it is produced due to the impact of Dynamic Forces.

Cloudy water consists of air bubbles and is harmless.

Biotic things have life and posses characteristics of living beings such as eating, walking, reproducing etc.

Answer:

b) methanol, bp = 65°C.

Explanation:

Hello there!

In this case, it turns out necessary for us to firstly remember that the vapor pressure of a liquid is the pressure exerted by the gaseous particles in dynamic equilibrium with the present liquid and thus, the higher the vapor pressure, the weaker the liquid's intermolecular forces because they turn unstable.

In such a way, we can infer that the liquid with the highest vapor pressure, will have the lowest boiling point and therefore, the answer will be b) methanol, bp = 65°C.

Regards!

Answer:

50% ISOPROPANOL / H2O - 1

25% ISOPROPANOL / H2O - 2

Pure water - 4

ISOPROPANOL / H2O - 3

Explanation:

More Isopropanol concentration is least polar. When the isopropanol is mixed with water its polarity increases. Pure water is most polar. The polarity of a substance is dependent on its ability to bent and mold in the shape as required.

Answer:

Diethyl ether

Explanation:

The retention factor is measure of how much interaction that exists between the solvent and the solutes. A high retention factor means that the solute travels too quickly through the mobile phase.

The value of Rf shows how good a solvent is in achieving separation of the components of a mixture by TLC.

If the Rf is moderate, then the solute does not travel too quickly through the column. If the solute travels too quickly through the column(too high Rf), minimum separation is achieved. If the Rf is too low, the solute has more affinity for the stationary phase than it does for the mobile phase hence separation is not feasible.

We can see that in both cases, diethyl ether has a moderate Rf hence it achieves a better separation of compound A and B than pentane.

Answer:

A

Explanation:

The processes engineers take to build technology are outlined by the engineering process, which is defined as identifying a need, learning more about it, making a plan to meet it, putting into practice, evaluating the results, and looking for improvements. So, the correct option is B.

Process engineering is described as the interpretation and application of the basic natural laws and principles that enable people to convert energy and materials into goods that are beneficial to society on an industrial scale.

The engineering process, which is defined as identifying a need, learning more about it, creating a plan to address it, putting the plan into practice, reviewing the outcomes, and seeking for improvements, provides an overview of the procedures engineers use to create technology.

Therefore, the correct option is B.

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Answer:

A: Is constant irrespective of mass of the gases

Explanation:

Avagadro's number, denoted by nA, is a number that represents the units in one mole of any substance. The number is 6.02214076 × 10²³ and the units can be atoms, molecules, ions, formula units etc.

That is;

1 mole of a substance = 6.022 × 10²³atoms, molecules, ions, electrons etc.

It is important to note that the Avagyadro's number is constant irrespective of mass of the gases that are involved.

Answer:

A

Explanation:

frequency is the product of time and wave length

Answer:

(B) 0.2Hz

Explanation:

took the test and it for sure was not 2.0Hz

Answer:

a. Alkene

b. Alkyne

c. Alkane

d. Alkyne

Explanation:

Hydrocarbons can be:

a. C₈H₁₆

Alkene. n = 8 and 2n = 2.8 = 16,

​b. C₄H₆

Alkyne. n = 4 and 2n-2 = 2.4-2 = 6.

​c. C₇H₁₆

Alkane. n = 7 and 2n+2 = 2.7+2 = 16.

​d. C₂H₂

Alkyne. n = 2 and 2n-2 = 2.2-2 = 2.

Answer:

[tex]MnO_4^-+8H^++5e^-\rightarrow Mn^{2+}+4H_2O[/tex]

Explanation:

Hello there!

In this case, since redox reactions are characterized by the presence of a reduction reaction, whereby the oxidation of the element decreases, and an oxidation reaction whereby the oxidation of the element increases.

In such a way, for the given chemical equation, we can see Fe is increasing its oxidation state from 2+ to 3+, which means it is oxidized. On the flip side, Mn is being reduced from 7+ (MnO₄⁻) to 2+ and this, the reduction half-reaction is:

[tex]MnO_4^-+8H^++5e^-\rightarrow Mn^{2+}+4H_2O[/tex]

Whereas five electrons are carried.

Regards!

Answer:

0.1

Explanation:

I know that because of the law of conservation of mass

Answer:9.6g

Explanation: thats the right answer

Answer:

See explanation

Explanation:

In TLC, the plate is spotted at a point above the solvent front and the solvent moves up the plate by capillary action leading to the separation of the various components of the mixture spotted on the plate.

However, if the TLC plate is allowed to remain in the developing chamber for too long such that the solvent front reaches the top of the plate, the components of the mixture will recombine at the top of the plate and cancel out any separation which may have occurred on the plate.

Explanation:

hope this helps you to understand :)

The theoretical yield of urea (CN, O, H,) for this reaction is = 9.88 g of urea

The percent yield for this equation is 176%

A chemical reaction is a procedure in which one or more materials are transformed into one or extra unique materials. inside the response, the atoms of the beginning materials are rearranged, forming new substances which have specific residences.

calculation:-

2 NH3, (g) + Co2, (g) → CN2,OH4, (s) + H20 (l)

2*17 g of ammonia produces 60g of urea.

5.6 g of ammonia produces = (60/34)*5.6

                                               = 9.88 g of urea

60g of urea produced by 34 g of ammonia

  13.74 g of urea produced by =34/60*13.74

                                         = 7.78 g

percentage yield =  13.74 g of urea are produced/7.78

                            =1.76*100

                          ⇒ 176%

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Answer:

Ketones and ketoacids are alternative fuels for the body that are made when glucose is in short supply. They are made in the liver from the breakdown of fats. Ketones are formed when there is not enough sugar or glucose to supply the body's fuel needs. This occurs overnight, and during dieting or fasting.

Explanation:

Answer:

The law is observed in the given equation.

Explanation:

CaCO₃ + 2HCI → CaCI₂ +H₂O + CO₂

In order to find out if the law of conservative mass is followed, we need to count how many atoms of each element are there in both sides of the equation:

As the numbers for all elements involved are the same, the law is observed in the given equation.

Answer: The balanced molecular equation for the precipitation reaction is [tex]K_2CO_3(aq)+2CuF(aq)\rightarrow Cu_2CO_3(s)+2KF(aq)[/tex]

Explanation:

A precipitation reaction is defined as the reaction where a solid precipitate (solid substance) is formed at the end of the reaction. It is insoluble in water.

When potassium carbonate reacts with copper (I) fluoride, it leads to the formation of solid copper (I) carbonate and potassium fluoride solution.

The balanced chemical equation follows:

[tex]K_2CO_3(aq)+2CuF(aq)\rightarrow Cu_2CO_3(s)+2KF(aq)[/tex]

The precipitate formed is copper (I) carbonate

Answer:

the relative height of M⁺ : M+1 is; 0.7418 : 0.2228

The relative heights are; In order of increasing mass 100 : 30

Explanation:

Given the data in the question;

The M⁺ peak comes from all ¹²₆C atoms

so, the probability in cholesterol, C₂₇H₄₈O is ( 98.9% )²⁷ = ( 0.989 )²⁷ = 0.7418

The M+1 peak comes from the isotopic carbon ¹³₆C.

so, the probability in cholesterol is ⇒ 1.10% × ( 98.9% )²⁶ = 0.011 × ( 0.989)²⁶

The probability for 27 carbons is ⇒  27 × 0.011 × ( 0.989)²⁶ = 0.2228

Therefore, the relative height of M⁺ : M+1 is; 0.7418 : 0.2228

The relative heights are; In order of increasing mass 100 : 30  

Answer:

See explanation and image attached

Explanation:

The compound SF4 is sulphur tetraflouride. It has a zero formal charge and has a total of 34 valence electrons.

The central atom in the molecule is sulphur in an sp3d hybridization state hence the molecule has a trigonal bipyramidal electron geometry. Since it is a molecule of the sort AX4E; it gives a see-saw molecular shape.

The structure of the molecule is shown in the image attached to this answer.

In the Lewis structure of SF₄ , sulfur (S) is the central atom bonded to four fluorine (F) atoms. Lewis structure for SF₄ is attached to the image below.

Each bond is represented by a line, indicating a pair of shared electrons between the bonded atoms. The fluorine atoms are placed around the sulfur atom, and each fluorine atom has a lone pair of electrons that are not involved in bonding.

Sulfur (S) is in Group 16 of the periodic table, so it has 6 valence electrons. Fluorine (F) is in Group 17 and has 7 valence electrons each.

Since we have 4 fluorine atoms, add 4 times the number of valence electrons for fluorine (4 × 7 = 28). The total number of valence electrons in SF₄ is 6 + 28 = 34.

Since each fluorine atom requires 8 electrons (octet rule), each F atom will have 6 lone pairs (12 electrons) around it.

The sulfur atom (S) has a formal charge of +2 (6 valence electrons - 4 bonds - 0 lone pairs), while the fluorine atoms (F) have a formal charge of -1 (7 valence electrons - 0 bonds - 6 lone pairs).

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Answer:

2NaCl + CuCO3

FeCl2 + BaSO4

CuCO3 + Ca(NO3)2

Explanation:

Presumably this is a double replacement reaction.

A+B + C+D → A+D + C+B

It seems I may be wrong so please try to work out the problem yourself to double check, keeping in mind the charges of each compound.

Answer:

english pls so i can answer

Explanation:

C4H10 + 13/2O2 ---------> 4CO2 + 5H2O

so u can work out the amount of moles by doing

moles=mass/mr

mr of C4H10 is 12 × 4 + 10 =58

=7.269/58

= 0.125moles

Then u can use the molar ratio which is

6.5:4

0.125 ÷6.5 × 4 = 0.0769moles

hope this helps:)

Answer:

density = d = 19.3g/cm^3

Mass of gold = m= 20g

now

we know,

density = mass / volume

or volume = mass/ density

volume = 20/19.3 = 1.036cm^3

Explanation:

Answer:

The specific heat of the metal is 0.106 [tex]\frac{cal}{g*C}[/tex]

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

There is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case:

Replacing:

26.5 cal= c* 50 g* 5 C

Solving:

[tex]c=\frac{26.5 cal}{50g*5 C}[/tex]

c= 0.106 [tex]\frac{cal}{g*C}[/tex]

The specific heat of the metal is 0.106 [tex]\frac{cal}{g*C}[/tex]

Answer:

a) 320: two significant figures.

b) 2,366: four significant figures.

c) 73.0: three significant figures.

d. 532.5: four significant figures.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to write each number by knowing we move the decimal places to the right as much as the exponent is, and also, we count every figure, even zeros, because they are to the right of the first nonzero digit:

a) 320: two significant figures because the rightmost zero is not preceded o followed by a decimal place.

b) 2,366: four significant figures.

c) 73.0: three significant figures, because the zero is followed by the decimal place.

d. 532.5: four significant figures.

Regards!

Answer:

Well, they are very durable unlike other packaging food materials, they can be recycled. But, the internet says allumninum cans are much better. and it could be better because you can keep the canned milk cool (cold) for a long lasting time. (keep it in the fridge if you want it to stay cold even longer)

Answer:

A. True

Explanation: