Why is it difficult to classify dissolving as simply a physical or a chemical change? (1 point)
O Some substances keep the same molecular structure when they break down, and others do not.
O Some substances release energy when they dissolve, and some absorb energy.
O Some substances taste the same after they dissolve, and others do not.
O Some substances keep the same color when they dissolve, and others do not.

Answers

Answer 1

Answer:

It is difficult because of C

Explanation:

Answer 2

The correct answer is:Some substances keep the same molecular structure when they break down, and others do not.

Some substances change their form when they dissolve and some do not. Dissolution can sometimes be regarded as a sort of reaction between a chemical substance and water.

Usually, we can consider dissolution of a substance in water as a sort of chemical reaction for some substances. For instance, an ionic substance interacts with water to form ions. similarly, some salts become hydrolysed in water and give acidic/basic solutions as  result of that.

However, some substances do not interact with water upon dissolution. They rather remain as molecular entities because they are not composed of ions.

We can see that some substances keep the same molecular structure when they break down, and others do not keep the same molecular structure  when they dissolve hence it is difficult to classify dissolving as a physical or a chemical change.

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Related Questions

what are the functional group
present in ch3cooh and C2h5oh​

Answers

CH3COOH - COOH carboxylic acid
C2H5OH - OH Alcohol

the -OH group cannot exhibit inductive effect? true/false, and reason for ur choice​

Answers

Answer:

false

Explanation:

The inductive effects are know as the ability of the atom or a group to create polarization and electronic density long the covalent bond and it needs a higher density. The -OH group cannot exhibit the indictive effects as it becomes --O.

Hazmat products warnings or labels allowed in fc

Answers

Answer:

The Hazmat products warnings or labels allowed in fc include:

1. Fully Regulated Aerosol Placard

2. Fully Regulated Flammable Solid Placard  

3. Fully Regulated Flammable  

4. Lithium-Ion/Metal Battery label

Explanation:

Hazmat products (including explosives, flammable liquids and solids, and gases, etc.) are classified as dangerous substances and materials that pose a risk to people during their storage, handling, or transportation.  The requirement for this Hazmat classification is to show that the identified products require diligence, carefulness, and alertness in handling, transporting, and storing them.  The reason for this is that mishaps can occur.  Some of them can also cause fire outbreaks.

Water put into a freezer compartment in the same refrigerator goes into a state of less molecular disorder when it freezes. Is this an exception to the entropy principle

Answers

Answer:

No it is not an exception to this principle

Explanation:

Work was carried out by this compressor to reduce the entropy of ice. What this means is that the ice gave out heat which is as a result  of the work that the compressor was putting in. there are violations of this principle

the entropy principle has that the entropy of the universe is always going to be more than 0 (system + surrounding). in this question, the that of the system is negative while that of the surrounding is positive.  As the refrigerator was cooling the water, the air outside was getting heated.  Outside this refrigerator, the gain in entropy is more than the entropy that was lost in the water.

the entropy of the universe once again is more than 0.

Write the structure of butanoate ion.

Answers

Answer:

Explanation:

Molecular FormulaC4H7O2

Average mass87.098 Da

Monoisotopic mass87.045151 Da

The cation of the salt is sodium ion, and the anion is aurothiosulfate ion. Based on the chemical formula of the salt, what must the charge be of the aurothiosulfate ion [Au(S2O3)2 n- ]

Answers

Answer:

3-

Explanation:

Sodium aurothiosulfate is a salt with the formula Na₃Au(S₂O₃)₂. The cation of the salt is sodium ion, and the anion is aurothiosulfate ion. We can determine the charge of the aurothiosulfate ion, considering that the sum of the positive and negative charges must be equal to the charge of the compound, which is zero.

3 × Na⁺ + 1 × Au(S₂O₃)₂ⁿ⁻ = 0

3 × +1 + 1 × Au(S₂O₃)₂ⁿ⁻ = 0

Au(S₂O₃)₂ⁿ⁻ = 3-

Hydrogen cyanide gas can be made by a two stepprocess. First, ammonia is reacted with oxygen gas to give nitrogen monoxide and water vapor. In the next step, nitrogen monoxide is reacted with methane (CH4) to give hydrogen cyanide gas. The by-products are water and hydrogen gas. A) Write the balanced equation for the two reactions.
B) When 24.2 g of ammonia and 25.1 g of methane are used, how many grams of hydrogen cyanide can be produced?

Answers

Answer:

38.34 g of HCN are produced

Explanation:

Our reactants for the first reaction are:

NH₃ and O₂

Products are: H₂O  and NO

Our reactants for the second reaction are:

NO and CH₄

Producs are: H₂, H₂O and HCN

The reactions are:

4NH₃ and 5O₂  →  6H₂O  + 4NO

2NO and 2CH₄  →  2HCN  + H₂ + 2H₂O

In the first step 4 moles of ammonia can produce 4 moles of NO, so ratio is 1:1

24.2 g . 1mol / 17 g = 1.42 moles of ammonia

We have produced 1.42 moles of NO.

25.1 g . 1 mol / 16 g = 1.57 moles of methane.

Ratio is 2:2. So, for 1.57 moles of methane, we need 1.57 moles of NO.

Moles are the same. As there is no enough NO, this is the limiting reactant.

Ratio with product is also 2:2.

Our 1.42 moles of NO have produced 1.42 moles of HCN.

We convert moles to mass: 1.42 mol . 27 g/mol = 38.34 g

If 16 grams of O2 react with excess C2H6, how many grams of CO2 will be formed? The formula mass of O2 = 32 amu and the formula mass of CO2 = 44amu. The balanced chemical equation is 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g)

Answers

Answer:5.17g of Co2

Explanation:

Precipitation of an ionic compound will occur upon mixing of desired reagents if the initial ion product is:_______
A) greater than the Ksp
B) equal to the pksp
C) equal to the Ksp
D) less than the Ksp

Answers

Answer:

A) greater than the Ksp

Explanation:

Given a solid ionic compound AB, it dissociates in water into its ions, as follows:

AB(s) → A⁺(aq) + B⁻(aq)

At equilibrium, the product of the concentrations of the ions is constant, and it is called Ksp:

AB(s) ⇄ A⁺(aq) + B⁻(aq)

Ksp = [A⁺][B⁻] ⇒ (concentrations at equilibrium)

Upon mixing the reagents for the formation of AB, the compound will precipitate if the initial ion product (Q) is greater than the Ksp. If Q is equal to Ksp, the ions are at equilibrium with the solid compound AB, and if is it less than the Ksp, the ions are soluble and no solid AB is formed yet.

Q = [A⁺][B⁻] ⇒ (initial concentrations)

Q = Ksp ⇒ saturated solution (at equilibrium)

Q< Ksp ⇒ unsaturated solution (ions are soluble)

Q> Ksp ⇒ precipitation of solid compound.

Therefore, the correct option is A) greater than the Ksp

Explain how the existence of isotopes relates to the number of neutrons within the nuclei of an element.

Answers

Answer:

because of it less attraction and its neutral position

Answer:

The existence of isotopes relates to the number of neutrons within the nuclei of an element because isotopes contain the same amount of protons (based on what element they are) but different number of neutrons in their nuclei. Because they have a different amount of neutrons, than the original element

,they also have a different atomic mass.

Explanation:

hope it helps!

Draw the structure of 2 methyl,but-3-ene

Answers

Answer:

Please find the structure attached as an image

Explanation:

Based on the characteristics ending name (-ene) of the organic compound above, it belongs to the ALKENE GROUP. Alkenes are characterized by the possession of a carbon to carbon double bond (C=C) in their structure.

- But-3-ene tells us that the organic compound has four straight carbon atoms with the C=C (double bond) located on the THIRD carbon depending on if we count from right to left or vice versa.

- 2 methyl indicates that the methyl group (-CH3) is located as an attachment on the second carbon (carbon 2).

N.B: In the structure attached below, the counting is from the left to right (→).

In Mexico, avocados are 39 pesos per kilogram. What is the cost in pesos of an
avocado that weighs 0.25 lb?
1kg = 2.201b

Answers

Answer:

The correct answer is - 4.5 pesos.

Explanation:

Given:

rate of per kg = 39 pesos

price for 0.25 lb = ?

Solution:

we know and given that,

1 kg = 2.20 lb

1 lb = 1000gm/2.20

then, the price for 0.25 lb would be:

=> (39/2.20)*0.25

= 4.4318 or 4.5 pesos

Determine the molecular formula of a compound if it is composed of 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen. The molar mass is 176.12 g/mol.
A) C3H8O3.
B) CH2O.
C) C2H3O2.
D) C3H4O3.

Answers

Answer:

No correct answer listed. See explanation for defense.

Explanation:

Given

C: 40.92% => 40.92g/100wt => (40.92/12)moles C = 3.41 moles O

H:   4.58% =>   4.58g/100wt =>      (4.58/1)moles H = 4.58 moles H

O: 54.50% => 54.5g/100wt =>     (54.5/16)moles O = 3.41 moles O

Empirical ratio => C : H: O => (3.41/3.41) : (4.58/3.41) : (3.41/3.41) => 1 : 1.34 : 1

=> C : H : O => 3(1 : 1.34 : 1) => 3 : 4 : 3 => Empirical Formula C₃H₄O₃

Molecular Weight = Empirical Formula Wt x N

         176.12          =           88  x  N

N = whole number multiple of empirical formula = 176.12/88 = 2

∴ Molecular Formula => (C₃H₄O₃)₂ => C₆H₈O₆

Note => Only ionic compounds (salts) have subscripts reduced to lowest whole number ratios. Molecular compounds as C₆H₈O₆ are not reduced to lowest whole number ratios. Therefore, there is no correct answer in the answer choice list for the 'Molecular Formula'. Doc :-)

13. What is the volume of 17.88 mol of Ar at STP?

Answers

Answer:

Explanation:

1 mol of ideal gas at STP occupies 22.4 (or 22.7 depending on the convention being used for STP) liters in volume. I will use 22.4 so 17.88*22.4 = 400.5 L

The substitution reaction of toluene with Br2 can, in principle, lead to the formation of three isomeric bromotoluene products. In practice, however, only o- and p-bromotoluene are formed in substantial amounts. The meta isomer is not formed. Draw the structures of the three possible carbocation intermediates, and explain why ortho and para products predominate over meta products.

Answers

Answer:

See explanation and image attached

Explanation:

Aromatic hydrocarbons undergo electrophillic substitution. Usually, substituted benzene is more or less reactive to electrophillic substitution compared to unsubstituted benzene.

Substituents on the benzene ring tend to direct the incoming electrophile during electrophillic substititution. The presence of the -CH3 group on toluene directs the incoming Br electrophile to the ortho/para position.

Where the incoming electrphile E is Bromine, we can see that in the ortho/ para product, the electron pushing -CH3 stabilizes the resonance structure formed and increases electron density at the ortho/para position via resonance compared to the meta product as we can see from the image attached. Hence, the ortho and para products predominate over meta products.

Image credit: Chemistry steps

When CH3NO2 burns in excess oxygen, it forms carbon dioxide, nitrogen dioxide and water. How many moles of oxygen are required to burn 17.10 mole(s) of CH3NO2

Answers

Explanation:

The given reaction is the combustion of CH3NO2.

The balanced chemical equation of the reaction is:

[tex]4CH_3NO_2+ 7O_2 ->4 CO_2+4NO_2+6H_2O[/tex]

So, from the balanced chemical equation, it is clear that:

4 moles of CH3NO2 --- 7 moles of oxygen gas is required.

then,

for 17.10 moles of CH3NO2 the following number of moles of oxygen is required.

[tex]The number of moles of O_2 required=17.10 mol. x \frac{7 mol}{4 mol} \\=29.925 mol[/tex]

Answer is :

29.9 mol of oxygen gas is required.

Please help me order these bonds urgent

Answers

Answer:

From least polar covalent to most polar covalent;

S-I< Br-Cl < N-H< Te-O

From most ionic to least ionic

Cs-F> Sr-Cl> Li- N> Al-O

Explanation:

Electro negativity refers to the ability of an atom in a bond to attract the shared electrons of the bond towards itself.

Electro negativity difference between two atoms is a key player in the nature of bond that exists between any two atoms. A large difference in electron negativity leads to an ionic bond while an intermediate difference in electro negativity leads to a polar covalent bond.

Based on electro negativity differences, the bonds in the answer have been arranged in order of increasing polar covalent nature or decreasing ionic nature.

what are the angles a and b in the actual molecule of which this is a lewis structure note for advanced students give the ideal angles and don t worry about small differences from the ideal that might be caused by the fact that different electron groups may have slightly different sizes

Answers

Answer:

The answer is "120 C  and 109.5 C".

Explanation:

The carbon atom is hybridized by sp2. This angle of connection thus is 120 degrees. Alkene, specifically both carbons which are in the C=C, are an instance of carbon with sp2 hybridized atom's nucleus. Those three hybridized orbits were linked to certain other atoms forming sigma connections. Its remaining 2p orbital makes a pi link with 2p orbit by the side-overlap of all the other carbon. O is hybridized inside the [-OH] Group. The optimal bond angle therefore is [tex]109.5^{\circ}[/tex].

[tex]a= 120 \ C\\\\b= 109.5 \ C[/tex]

balanced equation of sulphur dioxide ​

Answers

Answer:

SO₂

Here you go :)

Have a wonderful day :D

how are aqi and aqhi similar

Answers

The AQI reports the current quality of the air relative to the measured amount of pollutant. AQHI on the other hand is a report on how the air quality affects human health.

In a first order reaction 40% of reactant gets converted into product in 30 minutes. What time would it require to convert 75% into product? ​

Answers

56 minutes and 15 seconds I believe

In a first order reaction 40% of reactant gets converted into product in 30 minutes. The time would it require to convert 75%  into product is 81.57 minutes.

What is first order reaction?

First order reaction is defined as a chemical reaction in which the concentration of just one ingredient directly affects the pace of the reaction. If the first-order reactant concentration is doubled in these reactions, the reaction rate will likewise double. Chemical reactions classified as first order kinetics have rates of reaction that depend on the molar concentration of one component.

First order reaction = 2.303 / t log a / (a-x)

k = 2.303 / 30 log 100 (100 - 40)

k = 0.0767 log 1.66

k = 0.017 min⁻¹

The time required to convert 75 % product

t = 2.303 / 0.017 log 100 (100 - 75)    

t = 135.5 log 4

t = 135.5 x 0.602

t = 81.57 minutes

Thus, in a first order reaction 40% of reactant gets converted into product in 30 minutes. The time would it require to convert 75%  into product is 81.57 minutes.

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Approximately how much energy (in kJ) would be released during the formation of the bonds in 2.00 mol of acetone molecules

Answers

Answer:

7822 kJ

Explanation:

The formula for acetone is: CH3COCH3

From the standard bond energy(enthalpy):

C - H bond = 412

C - C bond = 348

C = O bond = 743

From the structure of an acetone

C is bonded to H in six places;

so, for  C- H bond = 6 × 412 = 2472

C is only bonded to two other carbon atoms

For C - C bond = 2 × 348 = 696

Carbon is only doubly bonded to an oxygen atom

For C = O bond = 1 × 743 = 743

The total net energy bond in a mole = (2472 + 696 + 743) kJ/mol

= 3911 kJ/mol

Finally, in 2 moles of acetone, the required amount of energy will be:

= 3911 kJ/moles × 2 moles

= 7822 kJ


The burning of paper is an example of which type of change?
A. An atomic change
B. A chemical change
C. A physical change
D. A phase change

Answers

Answer: B. A chemical Change

Explanation:

The Burning of paper changes the paper into a new substance (ash). So the ashes cannot be reversed into paper, therefore it is a chemical change.

Which of the following is an example of matter?
a) Hydrogen atom
b) Water molecule
c) Oxygen gas
d) All of the above

Answers

Answer:

All of the above

Explanation:

Molecules make up matter so they are considered matter as well.

Hope it helps c:

Name the functional group in the
following molecule:

Answers

Answer:

B. Aromatic

Explanation:

Functional groups are groups that differentiate a specific organic compound from others. A functional group determines the chemical property of the compound that possesses it.

For example, just like alkene and alcohol functional groups have characteristics double bond (=) and hydroxyl (OH) group respectively, the image in the attachment of this question has a BENZENE RING at the core of its structure, hence, the organic compound can be regarded to have an AROMATIC FUNCTIONAL GROUP.

Answer:

(B) aromatic

Explanation:

A step by step explanation

In Experiment 1, salicylic acid was treated with an excess of acetic anhydride to synthesize aspirin. Once the reaction went to completion, water was added to the flask and the solution was heated. What was the primary reason for adding water

Answers

Answer:

See explanation

Explanation:

Aspirin is a very important pain killer. The production of aspirin involves a reaction between salicylic acid and excess acetic anhydride.

Usually, a small amount of a mineral acid is added as a catalyst.

Aspirin is actually acetyl salicylic acid. When this substance is formed, the substance is not really soluble in water. Addition of water leads to the precipitation of the aspirin product.

Hence, the addition of water is mostly to precipitate the pure aspirin product after reaction.

What is the pH of a solution prepared by mixing 100.00 mL of 0.020 M Ca(OH)2 with 50.00 mL of 0.100 M NaOH? Assume that the volumes are additive?a. 12.78.b. 13.25.c. 12.67.d. 12.95.

Answers

Answer:

The pH of the solution is 12.78.

Explanation:

The pOH (or potential OH) is a measure of the basicity or alkalinity of a solution. The pOH is defined as the negative logarithm of the activity of the hydroxide ions. That is, the concentration of OH- ions:

pOH= - log [OH-]

On the other side, Molarity or Molar Concentration is the number of moles of solute that are dissolved in a certain volume. Molarity is calculated as:

[tex]Molarity= \frac{number of moles}{volume}[/tex]

Molarity is expressed in units: [tex]\frac{moles}{liter}[/tex]

In this case, the solution is prepared by mixing 100 ml (equal to 0.1 L, where 1000 mL = 1 L) of Ca(OH)₂ 0.020 M with 50 ml (equal to 0.05 L) of 0.100 M NaOH. Then, Ca(OH)₂ and NaOH are strong bases, so they dissociate completely. In the case of the first hydroxide, for each mole of Ca(OH)₂,

form two moles of OH-. In the case of sodium hydroxide, for each mole of hydroxide, one mole of OH- is formed. So, taking into account the definition of molarity, the number of moles of OH- that each hydroxide contributes to the solution is calculated as:

From Ca(OH)₂: 0.1 L* 0.02 M*2 = 0.004 moles

From NaOH: 0.05 L* 0.1 M= 0.005 moles

So, the amount of total moles of OH- is the sum that each hydroxide contributes to the solution: 0.004 moles + 0.005 moles= 0.009 moles

On the other hand, volumes are additive. Then: 0.1 L +  0.05 L= 0.15 L

Replacing in the definition of molarity the number of moles and the volume:

[tex][OH-]=\frac{0.009 moles}{0.15 L}[/tex]

Solving:

[OH-]= 0.06 [tex]\frac{moles}{liter}[/tex]

Replacing in the definition of pOH:

pOH= - log 0.06

pOH= 1.22

The following relationship can be established between pH and pOH:

pH + pOH= 14

Being pOH= 1.22 and replacing:

pH + 1.22= 14

pH= 14 - 1.22

pH= 12.78

The pH of the solution is 12.78.

What is the fourth quantum number of the 3p electron in aluminum,
1s^2 2s^2 2p^6 3s^2 3p^1?
A. ms = -1
B. ms = +1/2
C. ms=0
D. ms = +1​

Answers

Explanation:

here's the answer to your question

The quantum numbers are defined as the set of four numbers with the help of which we can get complete information about the electrons in an atom. The fourth quantum number is the spin quantum number. Here ms for 3p electron in 'Al' is ms = + 1/2. The correct option is B.

The quantum number which describes the spin orientation of the electron is defined as the spin quantum number. Since the electron can spin only in two ways, clockwise and anti-clockwise, the spin quantum number can have either the value +1/2 or -1/2 depending upon the direction of spin.

Thus for 3p electron in 'Al' ,ms is option B.

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Caffeine is a bitter stimulant drug and is found in varying quantities in seeds, leaves, and so on.

a. True
b. False

Answers

Answer:

The answer Is B.....False

B is. the correct answer

Please help me I am so loss

Answers

Answer:

19.25g of C4H10

Explanation:

2C4H10

2×12×4+2×1×10

=116g

8CO2

=8×12+8×16×2

=352 g

116g of C4H10 produces 352 g of CO2

So, x g of C4H10 produces 58.4g of CO2

(cross multiply)

352 x=116×58.4

x=116×58.4÷352

x=19.25g of C4H10

Answer:

19.25g of C4H10

2C4H10

2×12×4+2×1×10

=116g

8CO2

=8×12+8×16×2

=352 g

116g of C4H10 produces 352 g of CO2

So, t g of C4H10 produces 58.4g of CO2

(cross multiply)

352 t=116×58.4

t=116×58.4÷352

t=19.25g of C4H10

Explanation:

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