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2 years ago

11

Which of the following is a chemical change? A. soil drying as water evaporates B. a rock eroding as the wind removes particles

from it C. a solution of salt water being diluted as water is added to it D. silver tarnishing as the silver metal reacts with sulfur

2 answers:

Colt1911 [192]2 years ago

7 0

Answer:

D

Explanation:

IT IS REACTING

maxonik [38]2 years ago

5 0

Answer:

Its D

Explanation:

I took the quiz

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When chemists convert ethene (C2H2) to ethanol (CH3CH2OH), they have a mixture of the two gaseous substances. Why do chemists th

emmainna [20.7K]

Answer:

to collect liquid ethanol and leave ethene as a gas because ethanol has hydrogen bonds

Explanation:

The chemist would be lesser than the temperature of the mixture as to collect the liquid ethanol and then leave ethene as a gas since the ethanol is a bond that should be hydrogen. Also -OH that available in the ethanol would be responsible for the hydrogen bonds also it is the main and significant molecular forice

So as per the given situation the above represent the answer

3 0

2 years ago

Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation. The reaction is C2H2(g) + 2H2(g) ⇌ C2H6(

sukhopar [10]

Answer:

-255.4 kJ

Explanation:

The free energy of a reversible reaction can be calculated by:

ΔG = (ΔG° + RTlnQ)*n

Where R is the gas constant (8.314x10⁻³ kJ/mol.K), T is the temperature in K, n is the number of moles of the products (n =1), and Q is the reaction quotient, which is calculated based on the multiplication of partial pressures by the partial pressure of the products elevated by their coefficient divide by the multiplication of the partial pressure of the reactants elevated by their coefficients.

C₂H₂(g) + 2H₂(g) ⇄ C₂H₆(g)

Q = pC₂H₆/[pC₂H₂ * (pH₂)²]

Q = 0.261/[8.58*(3.06)²]

Q = 3.2487x10⁻³

ΔG = -241.2 + 8.314x10⁻³x298*ln(3.2487x10⁻³)

ΔG = -255.4 kJ

4 0

3 years ago

In one step in the synthesis of the insecticide Sevin, naphthol reacts with phosgene as shown.

Serhud [2]

Answer:

Explanation:

Chemical equation:

C₁₀H₈O + COCl₂ → C₁₁H₇O₂Cl + HCl

A. How many kilograms of C₁₁H₇O₂Cl form from 2.5×10*2 kg of naphthol?

Given data:

Mass of naphthol = 2.5 ×10² kg ( 250×1000 = 250000 g)

Mass of C₁₁H₇O₂Cl = ?

Solution:

Number of moles of naphthol = mass/ molar mass

Number of moles of naphthol = 250000 g/ 144.17 g/mol

Number of moles of naphthol = 1734.1 mol

Now we will compare the moles of naphthol with C₁₁H₇O₂Cl.

C₁₀H₈O : C₁₁H₇O₂Cl

1 : 1

1734.1 : 1734.1

Mass of C₁₁H₇O₂Cl:

Mass = number of moles × molar mass

Mass = 1734.1 mol × 206.5 g/mol

Mass = 358091.65 g

Gram to kilogram:

1 kg×358091.65 g/ 1000 g = 358.1 kg

B. If 100. g of naphthol and 100. g of phosgene react, what is the theoretical yield of C11H7O2Cl?

Given data:

Mass of naphthol = 100 g

Mass of COCl₂ = 100 g

Theoretical yield of C₁₁H₇O₂Cl = ?

Solution:

Number of moles of naphthol:

Number of moles of naphthol = mass/ molar mass

Number of moles of naphthol = 100 g/ 144.17 g/mol

Number of moles of naphthol = 0.694 mol

Number of moles of phosgene:

Number of moles = mass/ molar mass

Number of moles = 100 g/ 99 g/mol

Number of moles = 1.0 mol

Now we will compare the moles of naphthol and phosgene with C₁₁H₇O₂Cl.

C₁₀H₈O : C₁₁H₇O₂Cl

1 : 1

0.694 : 0.694

COCl₂ : C₁₁H₇O₂Cl

1 : 1

1.0 : 1.0

The number of moles of C₁₁H₇O₂Cl produced by C₁₀H₈O are less so it will limiting reactant and limit the yield of C₁₁H₇O₂Cl.

Mass of C₁₁H₇O₂Cl:

Mass = number of moles × molar mass

Mass = 0.694 mol × 206.5 g/mol

Mass = 143.3 g

Theoretical yield = 143.3 g

C. If the actual yield of C11H7O2Cl in part b is 118 g, what is the percent yield?

Given data:

Actual yield of C₁₁H₇O₂Cl = 118 g

Theoretical yield = 143.3 g

Percent yield = ?

Solution:

Formula :

Percent yield = actual yield / theoretical yield × 100

Now we will put the values in formula.

Percent yield = 118 g/ 143.3 g × 100

Percent yield = 0.82 × 100

Percent yield = 82%

5 0

2 years ago

What is the best conclusion according to the energy diagram of the chemical reaction?

Mariulka [41]

"The reaction will absorb energy" is the best conclusion according to the energy diagram of the chemical reaction.

<u>Option: B</u>

<u>Explanation:</u>

The chemical bonds in the reactions are broken and formed as per process and contributed by three major steps: reactants, transition phase and product formation. Here transition phase is in equilibrium stage drived by activation energy, where bond is partially formed and partially broken, located at higher energy level then the starters.

The reactant's energy level is less relative to the products as seen in the endothermic reactions' energy diagram, which depicts that the products are less balanced than reactants. Here when the reaction is forced to the forward direction, then it direct towards the more unbalance entities. As energy is absorbed in the endothermic reaction from surrounding, thus the enthalpy change (ΔH) for the reaction is positive.

5 0

3 years ago

Concentration and ion moles are equal only when volume is what ?

siniylev [52]

Concentration and ion moles are equal only when volume is 1. Of 1.0 x 10-6 and 1.0 x 10-4, the larger number is 1.

3 0

2 years ago