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3 years ago

How does the A Hreaction relate to the A He of molecules involved in a reaction?

Chemistry

1 answer:

igor_vitrenko [27]3 years ago

8 0

Answer:

B. ΔHreaction = ΔH°f reactants- ΔH°f products

Explanation:

Using Hess's law, it is possible to sum ΔH of several related reactions to find ΔH of a particular reaction.

Having in mind Hess's law, ΔH°f is defined as the change in enthalpy during the formation of 1 mole of substance from its constituent elements (That is, pure elements, mono or diatomics, that have a ΔH° = 0).

For example, in ΔH°f of H₂O, the equation is:

H₂(g) + 1/2O₂(g) → H₂O(g)

The constituent elements with ΔH°f = 0 are H₂(g) and O₂(g).

Now, using Hess's law, you can sum the ΔH°f of substance in a reaction as, for example:

NaOH + HCl → H₂O + NaCl. ΔHr

The ΔH°f for each substance in the reaction is:

NaOH: Na + 1/2H₂ + 1/2O₂ → NaOH (1)

HCl: 1/2H₂ + 1/2Cl₂ → HCl (2)

H₂O: H₂ + 1/2O₂ → H₂O (3)

NaCl: Na + 1/2Cl₂ → NaCl (4)

The algebraic sum of (3) + (4) is -(ΔH°f reactants):

H₂ + 1/2O₂ + Na + 1/2Cl₂ → NaCl + H₂O ΔH°f reactants

This reaction - {(1)+(2)} ΔH°f products

NaOH + HCl → H₂O + NaCl.

ΔHr = ΔH°f reactants- ΔH°f products

In the example, we obtain this relationship that can be expanded for all reactions. Thus, right answer is:

<h3>B. ΔHreaction = ΔH°f reactants- ΔH°f products</h3>

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Why can't methanol, CH3OH, be used as a solvent for sodium amide, NaNH2? Sodium amide is nonpolar and methanol is polar. Sodium

Elodia [21]

Answer: sodium amide undergoes an acid -base reaction

Explanation:

sodium amide is a ionic compound and basically exists as sodium cation and amide anion. Amide anion is highly basic in nature and hence as soon as there is amide anion generated in the solution , Due to its very pronounced acidity it very quickly abstracts the slightly acidic proton available on methanol.

This leads to formation of ammonia and sodium methoxide.

Hence sodium amide reacts with methanol and abstracts its only acidic proton and form ammonia and sodium Methoxide.

Hence the 3rd statement is a corrects statement.

So we cannot use methanol for sodium amide because sodium amide itself would react with methanol and the inherent molecular natur of sodium amide would then change.

The 1st and 2nd statements both are incorrect because both the compounds methanol as well as sodium amide have dipole moments and hence are polar molecules.

The 4th statement is also incorrect as both the molecules have dipole moment and hence there would be ion-dipole forces operating between them.

The following reaction occurs:

NaNH₂+CH₃OH→NH₃+CH₃ONa

4 0

3 years ago

3. Fill in: Name the organelle or organelles that perform each of the following functions.

Mekhanik [1.2K]

A. Chloroplasts

B. The cell wall and the vacuole

C. Vacuoles

D. The mitochondrion

8 0

3 years ago

Does anyone know how to do this?

o-na [289]

Answer:

nop sorry

Explanation:

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2 years ago

Kipish [7]

Answer:

11 proton and 12 neutron

11 electrons

Explanation:

3 0

4 years ago

Please answer both questions.

Deffense [45]

Answer:

1)Krypton

2)11H

Explanation:

electrons=protons

protons=atomic number

mass number=protons+neutrons

mass number is the superscript

atomic number is the subscript.

1)The answer is Krypton because its atomic number= number of protons=number of electrons is 36.

mass number is 46+36=82.

2)subscript=atomic number=number of protons=number of electrons

i. H = electrons=1

=neutrons=0

ii. Cl=electrons=17

=neutrons=35-17=18

iii. Na=electrons=11

=neutrons=23-11= 12

so the answer is Hydrogen because it has 1 electron and 0 neutron.

I hope this helps.

6 0

3 years ago