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2 years ago

The activation energy of an endothermic reaction _____.

Chemistry

2 answers:

amm18122 years ago

8 0

Answer:

must be greater than the required ΔH

Explanation:

The activation energy is the minimum extra amount of energy required by reactant molecules to undergo a reaction.

For both exothermic and endothermic reactions we need activation energy.

Enthalpy is the energy difference between products and reactants.

For endothermic reactions, enthalpy is positive as the energy of products is more than the energy of reactants.

As activation energy will be greater than the energy of both the reactants and products, so it must be greater than the enthalpy of reaction.

Explanation:

Anon25 [30]2 years ago

3 0

Endothermic reactions are reactions that require heat in the course of the process. The heat of reaction in this case is positive which means the energy of the products is greater than the energy of the reactants. In this case, the answer to this problem would have to be 1. must be greater than the required ΔH

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A silver cube with an edge length of 2.38 cm and a gold cube with an edge length of 2.79 cm are both heated to 81.9 ∘C and place

never [62]

Answer:

The final temperature of the water when thermal equilibrium is reached is 23.54 ⁰C

Explanation:

Given data;

edge length of silver, a = 2.38 cm = 0.0238 m

edge length of gold, a = 2.79 cm = 0.0279 m

final temperature of silver, t = 81.9 ° C

final temperature of Gold, t = 81.9 ° C

initial temperature of water, t = 19.6 ° C

volume of water, v = 109.5 mL = 0.0001095 m³

Known data:

density gold 19300 kg/m³

density silver 10490 kg/m³

density water 1000 kg/m³

specific heat gold is 129 J/kgC

specific heat silver is 240 J/kgC

specific heat water is 4200 J/kgC

Calculated data

Apply Pythagoras theorem to determine the side of each cube;

Silver cube;

let L be the side of the silver cube

Taking the cross section of the cube (form a right angled triangle), the edge length forms the hypotenuse side.

L² + L² = 0.0238²

2L² = 0.0238²

L² = 0.0238² / 2

L² = 0.00028322

L = √0.00028322

L = 0.0168

Volume of cube = L³

Volume of the silver cube = (0.0168)³ = 4.742 x 10⁻⁶ m³

Gold cube;

let L be the side of the gold cube

L² + L² = 0.0279²

2L² = 0.0279²

L² = 0.0279² / 2

L² = 0.0003892

L = √0.0003892

L = 0.0197

Volume of cube = L³

Volume of the silver cube = (0.0197)³ = 7.645 x 10⁻⁶ m³

Mass of silver cube;

density = mass / volume

mass = density x volume

mass of silver cube = 10490 (kg/m³) x 4.742 x 10⁻⁶ (m³) = 0.0497 kg

Mass of Gold cube

mass of gold cube = 19300 (kg/m³) x 7.645 x 10⁻⁶ (m³) = 0.148 kg

Mass of water

mass of water = 1000 (kg/m³) x 0.0001095 (m³) = 0.1095 kg

Let the heat gained by cold water be Q₁

Let the heat lost by silver cube = Q₂

Let the heat lost by gold cube = Q₃

Let the final temperature of water = T

Q₁ = 0.1095 kg x 4200 J/kgC x (T–19.6)

Q₂ = 0.0497 kg x 240 J/kgC x (81.9–T)

Q₃ = 0.148 kg x 129 J/kgC x (81.9–T)

At thermal equilibrium;

Q₁ = Q₂ + Q₃

0.1095 x 4200 (T–19.6) = 0.0497 x 240 x (81.9–T) + 0.148 x 129 x (81.9–T)

459.9 (T–19.6) = 11.928 (81.9–T) + 19.092(81.9–T)

459.9T - 9014.04 = 976.9032 - 11.928T + 1563.6348 - 19.092T

459.9T + 11.928T + 19.092T = 9014.04 + 976.9032 + 1563.6348

490.92T = 11554.578

T = 11554.578 / 490.92

T = 23.54 ⁰C

Therefore, the final temperature of the water when thermal equilibrium is reached is 23.54 ⁰C

6 0

3 years ago

Describe several main ideas in chemistry

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Matter.

A force of attraction that holds atom together
When atoms react they form a chemical bond which is defined as a force of attraction that holds atom together. A force of attraction is defined as a kind of force that draws two or more objects together regardless of distance. There are two major categories of forces of attraction, one is intramolecular and intermolecular. Intramolecular forces is the presence of forces in atoms internally. While intermolecular is the force by which the force that is existent in two or more elements.

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3 years ago

What is the definition of bond?

JulijaS [17]

Join or be joined securely to something else, typically by means of an adhesive substance, heat, or pressure.

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2 years ago

7.) Regarding molecular formula and empirical formula for a particular compound... (A) the subscripts in the empirical formula m

S_A_V [24]

Answer:

Explanation:

i think the anwer would be that its elliptical orbit and the tilt an its axis.

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2 years ago

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The reaction of glucose, c6h12o6, with oxygen produces carbon dioxide and water. what is the sum of the coefficients in the bala

Misha Larkins [42]

The balanced equation for the given reaction:

C₆H₁₂O₆ (glucose) + 6O₂→ 6CO₂ + 6H₂O

So in the balanced equation the coefficients before glucose, oxygen, water and carbon dioxide are 1, 6, 6 and 6 respectively.

Therefore, the sum of the coefficients in the balanced equation

= 1 + 6 + 6 + 6

= 19

The correct answer is 19.

8 0

2 years ago