What's the name of a wave moving along a line?

How to draw Hess' Cycle for this question ?

NISA [10]

Answer : The standard enthalpy of formation of ethylene is, 51.8 kJ/mole

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The formation reaction of $C_2H_4$ will be,

$2C(s)+2H_2(g)\rightarrow C_2H_4(g)$ $\Delta H_{formation}=?$

The intermediate balanced chemical reaction will be,

(1) $C_2H_4(g)+3O_2(g)\rightarrow 2CO_2(g)+2H_2O(l)$ $\Delta H_1=-1411kJ/mole$

(2) $C(s)+O_2(g)\rightarrow CO_2(g)$ $\Delta H_2=-393.7kJ/mole$

(3) $H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(l)$ $\Delta H_3=-285.9kJ/mole$

Now we will reverse the reaction 1, multiply reaction 2 and 3 by 2 then adding all the equations, we get :

(1) $2CO_2(g)+2H_2O(l)\rightarrow C_2H_4(g)+3O_2(g)$ $\Delta H_1=+1411kJ/mole$

(2) $2C(s)+2O_2(g)\rightarrow 2CO_2(g)$ $\Delta H_2=2\times (-393.7kJ/mole)=-787.4kJ/mole$

(3) $2H_2(g)+2O_2(g)\rightarrow 2H_2O(l)$ $\Delta H_3=2\times (-285.9kJ/mole)=-571.8kJ/mole$

The expression for enthalpy of formation of $C_2H_4$ will be,

$\Delta H_{formation}=\Delta H_1+\Delta H_2+\Delta H_3$

$\Delta H=(+1411kJ/mole)+(-787.4kJ/mole)+(-571.8kJ/mole)$

$\Delta H=51.8kJ/mole$

Therefore, the standard enthalpy of formation of ethylene is, 51.8 kJ/mole

7 0

2 years ago

All of the following methods would increase the solubility of a solid solute, except for

cricket20 [7]

May i please have a(n) answer choices please because it would be a lot better if it was like that and then ill answer it

8 0

3 years ago

Dalton hypothesesized that atoms are indivisible and that all atoms of an element are identical. it is now known that

Katena32 [7]

i don't understand but atoms are made of electrons an protons and neutrons..

6 0

3 years ago

What property of water molecules allows water to dissolve many substances

hodyreva [135]

Answer:

Its high polarity

Explanation:

Solvent is the that part of solution which is present in large proportion and have ability to dissolve the solute. In simplest form it is something in which other substance get dissolve. The most widely used solvent is water, other examples are toluene, acetone, ethanol, chloroform etc.

Water is called universal solvent because of high polarity all polar substance are dissolve in it. Hydrogen is less electronegative while oxygen is more electronegative and because of difference in electronegativity hydrogen carry the partial positive charge while oxygen carry partial negative charge.

Water create electrostatic interaction with other polar molecules. The negative end of water attract the positive end of polar molecules and positive end of water attract negative end of polar substance and in this way polar substance get dissolve in it.

Example:

when we stir the sodium chloride into water the cation Na⁺ ions are surrounded by the negative end of water i.e oxygen and anion Cl⁻ is surrounded by the positive end of water i.e hydrogen and in this way all salt is get dissolved.

5 0

3 years ago

7th grade science help me plsssss

tigry1 [53]

1. Organism: (description) an individual animal, plant, or single-celled life form.

(example) Humans, squids, mushrooms, and vascular plants

2. Population: (description) A population is all the inhabitants of a particular

place

(example) All institutionalized elderly with Alzheimer's

All people with AIDS

3. Community: (description) A community is a social unit with commonality such as norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area or in virtual space through communication platforms.

(example) a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi

4. Ecosystem: (description) An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.

(example) agroecosystem, aquatic ecosystem, coral reef etc.

5. Biosphere: (description) The biosphere is the worldwide sum of all ecosystem

(example) An example of the biosphere is where live occurs on, above and below the surface of Earth.

mark me brainliestttt :)))

5 0

3 years ago