what must occur for a change to be a chemical reaction?
​

Answer:

Precipitation

Explanation:

Let's consider the balanced chemical equation between barium acetate and sodium carbonate to form barium carbonate and sodium acetate.

Ba(C₂H₃O₂)₂(aq) + Na₂CO₃(aq) → BaCO₃(s) + 2 NaC₂H₃O₂(aq)

Both products and reactants are salts. But, among the products, barium carbonate is solid. This allows us to classify it as a precipitation reaction.

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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Answer:

The pressure of the resulting mixture of gases will be 4.89 atm.

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. The universal constant of ideal gases R has the same value for all gaseous substances. The numerical value of R will depend on the units in which the other properties are worked.

In this case:

Replacing:

P* 35 L= 7 moles* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] * 298 K

Solving:

[tex]P=\frac{ 7 moles* 0.082 \frac{atm*L}{mol*K} * 298 K}{35 L}[/tex]

P= 4.89 atm

The pressure of the resulting mixture of gases will be 4.89 atm.

The pressure (in atm) of the resulting mixture of the gases is 4.89 atm

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

Mole of N₂ = 3 moles

Mole of O₂ = 4 moles

Total mole = 3 + 4 = 7 moles

Volume (V) = 35 L

Temperature (T) = 25 °C = 25 + 273 = 298 K

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

The pressure of the resulting mixture of the gases can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

P × 35 = 7 × 0.0821 × 298

P × 35 = 171.2606

Divide both side by 35

P = 171.2606 / 35

Therefore, the pressure of the resulting mixture of the gases 4.89 atm

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Answer:

false

Explanation:

Answer:5.17g of Co2

Explanation:

Answer:

1.59 M

Explanation:

What is the concentration (M) of CH₃OH a solution prepared by dissolving 11.7 g of CH₃OH sufficient water to give exactly 230 mL of solution?

Step 1: Given data

Step 2: Calculate the moles corresponding to 11.7 g of CH₃OH

The molar mass of CH₃OH is 32.04 g/mol.

11.7 g × 1 mol/32.04 g = 0.365 mol

Step 3: Calculate the molarity of the solution

M = moles of solute / liters of solution

M = 0.365 mol / 0.230 L = 1.59 M

Answer:

because electron molecule in floirine are tightly held to the nuclei dispersion force are relatively weak and in iodine they are strong

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.

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.

Explanation:

here are the answers for your questions

I basically converted the given grams to moles, and then multiplied that by the product-to-reactant ratio in the equation, and then convert that to grams

Answer:

Explanation:

1.

The reaction can be represented by the equation: Zn + 2 HCl -> ZnCl2 + H2

From the equation, molar ratio of Zn and ZnCl2 is 1:1.

Molar mass of Zn = 65.38

Molar mass of ZnCl2 = 65.38 + 35.45*2 = 136.28

So 6.0 grams of Zn will produce 6 / 65.38 * 136.28 = 12.5 grams

2.

As the only other product is copper (II) oxide, the reaction can be represented by the equation: CuCO3 -> CuO + CO2

From the equation, molar ratio of CuCO3 and CuO is 1:1.

Molar mass of CuCO3 = 123.55

Molar mass of CuO = 79.55

So 45.0 grams of CuCO3 will produce 45 / 123.55 * 79.55 = 28.96 grams

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.

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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Answer:

the entropy change for the system when 1.58 moles of CaCO3(s) react at standard conditions is 253.748 J/K

Explanation:

Given the data in the question;

CaCO₃(s)       →     CaO(s)     +     CO₂(g)  

1.58 moles        1.58 moles     1.58 moles

Since 1 mole of CaCO₃ gives 1 mole of CaO and 1 mole of CO₂

Thus, 1.58 mole of CaCO₃ gives 1.58 moles of CaO and 1.58 moles of CO₂.

Now,

At 298 K, standard entropy values are;

ΔS° ( CaCO₃ ) = 92.9 J/mol.K

ΔS° ( CaO )     = 39.8 J/mol.K

ΔS° ( CO₂ )      = 213.7 J/mol.K

So,

ΔS°[tex]_{system[/tex] = ∑ΔS°( product ) - ∑ΔS°( reactant )

ΔS°[tex]_{system[/tex] = [ ΔS°(CaO) + ΔS°( CO₂ ) ] - ΔS°( CaCO₃ )

we substitute

ΔS°[tex]_{system[/tex] = [ 39.8 J/mol.K + 213.7 J/mol.K ] - 92.9 J/mol.K

ΔS°[tex]_{system[/tex] = 160.6 J/mol.K

i.e, for 1 mol CaCO₃, ΔS°[tex]_{system[/tex] = 160.6 J/mol.K

Now, for 1.58 mol CaCO₃,

ΔS°[tex]_{system[/tex] = 1.58 mol × 160.6 J/mol.K

ΔS°[tex]_{system[/tex] = 253.748 J/K

Therefore, the entropy change for the system when 1.58 moles of CaCO3(s) react at standard conditions is 253.748 J/K

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

Answer:

a. 7278 K

b. Kc = 4.542 × 10⁻³¹

Explanation:

a.

The reaction is spontaneous when ΔG° < 0. We can calculate ΔG° using the following expression.

ΔG° = ΔH° - T × ΔS°

Then, the reaction will be spontaneous when,

ΔH° - T × ΔS° < 0

T > ΔH°/ΔS

T > (180.5 × 10³ J/mol)/(24.80J/mol⋅K)

T > 7278 K

b.

First, we will calculate ΔG° at 25 °C (298 K)

ΔG° = ΔH° - T × ΔS°

ΔG° = (180.5 × 10³ J/mol) - 298 K × (24.80J/mol⋅K) = 1.731 × 10⁵ J/mol

Then, we will calculate the equilibrium constant (Kc) using the following expression.

ΔG° = - R × T × ln Kc

-ΔG°/R × T =  ln Kc

-(1.731 × 10⁵ J/mol)/(8.314 J/mol.K) × 298 K =  ln Kc

Kc = 4.542 × 10⁻³¹

Answer:

C3H8 + 502+3CO2 + 4H20

Explanation:

In order to get this answer you would have to would balance out the carbons on the products side by multiplying CO2 by 3. The new equation will be 

C3H8 + 02 ----> 3CO2 + H20

Now, that the carbons are balanced, we will look at the hydrogens. We can multiply the number of waters on the product side by 4, to make 4 H20 molecules. This gives both sides of the equation 8 hydrogens. Next we can check our oxygens. There will be 10 oxygens on the products side and 2 on the reactants so to balance these out, we multiply the 02 on the reactants side by 5. 

````````````````````

Answer:

+5

Explanation:

Answer:

Explanation:

2Fe(s) + 3Pb(NO₃)₂(aq) = 3Pb(s) + 2Fe(NO₃)₃(aq)

Half ionic reactions

2Fe(s) = 2Fe⁺³ + 6e

3Pb⁺² + 6e = 3 Pb(s)

In the first reaction Fe is oxidised to Fe⁺³ because its oxidation number increases from zero to + 3 .

In the second reaction , Pb⁺² is reduced to Pb (s) because its oxidation number is reduced from + 2 to zero.

Answer:

The answer Is B.....False

Answer:

If you contact water with a gas at a certain temperature and (partial) pressure, the concentration of the gas in the water will reach an equilibrium ('saturation') according to Henry's law.

Explanation:

This means: if you increase the pressure (e.g. by keeping the vial closed), the CO2 concentration will increase. So it simply depends what concentration you need for your assay: 'CO2-saturated' water at low pressure or 'CO2-saturated' water at high pressure.

Answer:

See explanation

Explanation:

Given Einstein's theory of relativity, we have that;

E= mc^2

m= mass of the substance

c= speed of light

For one gram of the substance,

E= 1 ×10^-3 × (3 × 10^8)^2

E = 9 × 10^13 J

For 8.7 g of matter;

E = 8.7 × 10^-3× (3 × 10^8)

E= 7.83 ×10^ 14 J

Answer:

C) Both will require the same amount because the concentrations are equal.

Explanation:

The pH of a solution is defined as:

pH = -log [H+]

This H+ is the ion that reacts with OH- (From NaOH) as follows:

H+ + OH- → H2O

When all H+ reacts, we can say the solution was neutralized.

Now, as both, the solution with the weak acid and the solution with strong acid have the same pH, we can say that their [H+] is the same. Assuming the volume of both solutions is the same:

Both will require the same amount because the concentrations are equal.

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

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 :-)

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!

Answer:

ATP hydrolase

Explanation:

Enzymes are biological catalysts which perform diverse functions in the body. Enzymes are specific in their mode of action because an enzyme fits into its substrate as a key fits into a lock.

The particular enzyme that catalyzes the breakdown of ATP to ADP is ATP hydrolase. The phosphate released by the action of this enzyme is used in the phosphorylation of other compounds thereby making them more reactive.

Explanation:

Normality is one of the concentration terms.

It is expressed as:

[tex]N=\frac{mass of the substance}{equivalent mass}* \frac{1}{volume of solution in L.}[/tex]

The volume of the solution is 425 mL.

Mass of sulfuric acid given is:

[tex]mass=volume * purity* density\\ = 75 mL * 0.966 * 1.83 g/mL\\\\=132.5 grams\\[/tex]

The equivalent mass of sulfuric acid is 49.0g/equivalents

Hence, the normality of the given solution is:

[tex]N=\frac{132.5g}{49.0g/equi.} *\frac{1000}{425mL} \\Normality=6.36N[/tex]

Answer is: 6.36N.

Answer:

γ−Hydrogen is easily replacable during bromination reaction in presence of light , because Allylic substitution is being preferred.

Explanation:

that's all

γ−Hydrogen is easily replacable during bromination reaction in presence of light , because Allylic substitution is being preferred.

Explanation:

I have no idea about this