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2 years ago

Which is an example of an exothermic process?

Chemistry

2 answers:

Diano4ka-milaya [45]2 years ago

7 0

<h3>Question 1</h3>

An example of an exothermic process is, A hot pack feels warm when chemicals in it combine.

<h2>Further Explanation;</h2><h3>Energy changes in chemical reactions</h3>

Chemical reactions are accompanied by energy changes, as energy is either absorbed to break chemical bonds or released when bonds are formed.
Chemical reactions are therefore classified as endothermic reactions or exothermic reactions.

<h3>Exothermic reactions </h3>

Exothermic reactions are types of reaction that release energy to the surrounding.
In these reactions energy is released when new bonds are formed during the reactions. More energy is released when bonds are formed in the products than is used to break bonds in the reactants.
Therefore exothermic reactions have a negative (-) enthalpy change (ΔH).

<h3>Endothermic reactions </h3>

Endothermic reactions are type of reactions that absorb energy from the surroundings.
In these type of reactions more energy is absorbed when bonds of the reactants are broken than the energy released when bonds of the products are formed.
Endothermic reactions have a positive (+) enthalpy change (ΔH).

Keywords: Chemical reactions, energy changes in chemical reactions, exothermic reactions, endothermic reactions.

<h2>Question 2</h2>

The statement that describes the reaction;

N2(g) + 3H2(g)---> 2NH3(g) + 93 kJ is

The reaction is an endothermic reaction because energy is absorbed

<h2>Further Explanation;</h2><h3>Enthalpy of a reaction (ΔH)</h3>

Enthalpy chnage of a reaction or heat change is the difference between the enthalpy of products and the enthalpy of reactants.
Enthalpy change can be used to determine whether a reaction is exothermic or endothermic.
ΔH = energy used in bond breaking of reactant + energy released in bond formation of product.

<h3>Endothermic reactions</h3>

Endothermic reactions have a positive (+) enthalpy change (ΔH) because less energy is released when the products are formed compared to the energy used to break up the bonds in reactants.

<h3>Exothermic reactions </h3>

Exothermic reactions have a negative(-) enthalpy change (ΔH) since more energy released when the products are formed compared to energy used to break bonds in reactants.

Keywords: Enthalpy change, heat change, exothermic reactions, endothermic reactions.

<h3>Learn more about</h3>

Energy changes in chemical reactions: brainly.com/question/2217125
Ethalpy change; brainly.com/question/1127247
Endothermic reactions: brainly.com/question/1127247
Exothermic reactions: brainly.com/question/1831889

Level: High school

Subject: Chemistry

Topic: Chemical reactions

Sub-topic: Energy changes in chemical reactions

Gwar [14]2 years ago

5 0

1) Answer: A hot pack feels warm when chemicals in it combine.

Explanation: Reactions or process in which heat is released(produced) are known as exothermic reactions or process and those in which the heat is absorbed are known as endothermic reactions or process.

If a beaker feels cools when chemical in it react then it means the chemicals have absorbed the heat energy from its surroundings and so it is an example of an endothermic process.

A hot pack feels warm when chemicals in it combine means the energy is released in the chemical reaction and so it is an example of an exothermic process.

Plants use the sun's energy for photosynthesis which is a process of forming food for the plants. Energy acts as a reactant in this process and so it is an example of endothermic process.

Frying an egg by heating it on a stove is an example of an endothermic process as the heat is required to fry the egg.

So, the only exothermic process is the second one, "A hot pack feels warm when chemicals in it combine."

2) In the given equation, heat is written as a product means the heat is released in the equation and so it is an example of an exothermic reaction.

So, the correct choice is the last one " It is exothermic because energy is released."

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The volume of a given mass of agas is 360cm cubic at 50 degrees and 700 milimetres Hg .find it's volume at s.t.p

saveliy_v [14]

Answer:

V₂ =279.9 cm³

Explanation:

Given data:

Initial volume = 360 cm³

Initial temperature = 50°C

Initial pressure = 700 mmHg

Final volume = ?

Final temperature = 273 k

Final pressure = 1 atm

Solution:

According to general gas equation:

P₁V₁/T₁ = P₂V₂/T₂

Solution:

<em>We will convert the mmHg to atm.</em>

700/760 = 0.92 atm

<em>and °C to kelvin.</em>

50+273 = 323 K

P₁V₁/T₁ = P₂V₂/T₂

V₂ = P₁V₁ T₂/ T₁ P₂

V₂ = 0.92 atm × 360 cm³ × 273 K / 323 K ×1 atm

V₂ = 290417.6 atm .cm³. K / 323 k. atm

V₂ =279.9 cm³

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3 years ago

Which is true about the dissolving process in water?

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Water molecules move througout the solute

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3 years ago

Read 2 more answers

a 25.0-ml volume of a sodium hydroxide solution requires 19.6 ml of a 0.189 m hydrochloric acid for neutralization. a 10.0- ml v

Rashid [163]

<u>Concentration of NaOH = 0.148 molar, M</u>

<u>Concentration of H3PO4 = 0.172 molar, M</u>

<u></u>

Concentration x Volume will give the number of moles of solute in that volume. C*V = moles

Concentration has a unit of (moles/liter). When multiplied by the liters of solution used, the result is the number of moles.

Original HCl solution: (0.189 moles/L)*(0.0196 L)= 0.00370 moles of HCl

The neutralization of 25.0 ml of sodium hydroxide, NaOH, requires 0.00370 moles of HCl. The reaction is:

NaOH + HCl > NaCl and H2O

This balanced equation tells us that neutralization of NaOH with HCl requires the same number of moles of each. We just determined that the moles of HCl used was 0.00370 moles. Therefore, the 25.0 ml solution of NaOH had the same number of moles: 0.00370 moles NaOH.

The 0.00370 moles of NaOH was contained in 25.0 ml (0.025 liters). The concentration of NaOH is therefore:

<u>(0.00370 moles of NaOH)/(0.025 L) = 0.148 moles/liter or Molar, M</u>

====

The phosphoric acid problem is handled the same way, but with an added twist. Phosphoric acid is H3PO4. We learn the 34.9 ml of the same NaOH solution (0.148M) is needed to neutralize the H3PO4. But now the acid has three hydrogens that will react. The balanced equation for this reaction is:

H3PO4 + 3NaOH = Na3PO4 + 3H2O

Now we need <u><em>three times</em></u> the moles of NaOH to neutralize 1 mole of H3PO4.

The moles of NaOH that were used is:

(0.148M)*(0.0349 liters) = 0.00517 moles of NaOH

Since the molar ratio of NaOH to H3PO4 is 3 for neutralization, the NaOH only neutralized (0.00517)*(1/3)moles of H3PO4 = 0.00172 moles of H3PO4.

The 0.00172 moles of H3PO4 was contained in 10.0 ml. The concentration is therefore:

(0.00172 moles H3PO4)/(0.010 liters H3PO4)

<u>Concentration of H3PO4 = 0.172 molar, M</u>

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9 months ago

The jet stream is one of the key winds that moves air masses. in which direction does the jet stream in the united state general

OleMash [197]

The jet stream is one of the key winds that moves air masses at the direction from west to east it moves.

<h3>What are jet streams?</h3>

Jet streams are strong winds which are flow in the form of narrow bands in the upper part of the atmosphere. On the earth these winds are flows near the altitude of the tropopause. These winds carries weather systems and blows toward the colder northern air and due to the rotation of earth, its direction is from west to east.

Hence jet streams move winds from west to east direction.

To know more about jet streams, visit the below link:
brainly.com/question/791542

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2 years ago

The pH of a 1.0M solution of butanoic acid HC4H7O2 is measured to be 2.41. Calculate the acid dissociation constant Ka of butano

Lubov Fominskaja [6]

Answer:

Ka = 1.52 E-5

Explanation:

CH3-(CH2)2-COOH ↔ CH3(CH2)2COO- + H3O+

⇒ Ka = [H3O+][CH3)CH2)2COO-] / [CH3(CH2)2COOH]

mass balance:

⇒<em> C</em> CH3(CH2)2COOH = [CH3(CH2)2COO-] + [CH3(CH2)2COOH] = 1.0 M

charge balance:

⇒ [H3O+] = [CH3(CH2)2COO-]

⇒ Ka = [H3O+]²/(1 - [H3O+])

∴ pH = 2.41 = - Log [H3O+]

⇒ [H3O+] = 3.89 E-3 M

⇒ Ka = (3.89 E-3)² / ( 1 - 3.89 E-3 )

⇒ Ka = 1.519 E-5

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3 years ago