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3 years ago

In an exothermic chemical reaction:____.

Chemistry

1 answer:

erica [24]3 years ago

3 0

Answer:

Explanation:

Think of 'exo' as exit and 'thermic' as relating to thermal energy/ heat. Thus, an exothermic release thermal energy as the reaction proceeds.

In an exothermic reaction, the total energy of the products is lesser than that of the reactants and ΔH (change in energy) is less than zero.

When heat is absorbed as the reaction proceeds, the chemical reaction is an endothermic reaction.

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BRAINLIESTTT ASAP!! PLEASE HELP ME :) Draw and label all parts of a wave.

Airida [17]

Answer: see the photo attached. (:

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3 years ago

How many different sets of equivalent protons are there for para-xylene (1,4-dimethylbenzene)? only 1 two three four?

ELEN [110]

Answer:

Two

Step-by-step explanation:

There are two ways to determine the number sets of equivalent protons in a compound.

(a) By substitution

Replace each H with a different group and see if you get a different compound

For example, the six CH₃ H atoms are an equivalent set, because, if I replace any one of them, I will always get the same compound: 1-chloromethyl-4-methylbenzene (Fig. 1).

Similarly, the four aromatic H atoms are an equivalent set. If I replace any one of them, I will always get the same compound: 2-chloro-1,4-dimethylbenzene (Fig. 2).

Thus, there are two sets of equivalent protons in p-xylene.

(b) By symmetry

Two atoms are equivalent if one can be converted into the other by a symmetry operation on the molecule.

The methyl hydrogens can be interconverted by a combination of reflections about the AB and CD mirror planes and by rotations about the C-C bonds to the ring (Fig. 3).

Similarly, the four aromatic H atoms can be interconverted by a combination of reflections about the AB and CD mirror planes.

Again, we find two sets of equivalent protons.

7 0

3 years ago

Below is a list of terms used in characterizing solutions. Enter the correct term for each sentence. Note that not all of the te

AlladinOne [14]

Answer:

molality, mole fraction, solvent, solute, molarity.

Explanation:

The expression of concentration that provides the moles of solute per kilograms of solvent is molality.

$b=\frac{n_{solute}}{m_{solvent}(kg)}$

If you place 5 moles of sodium chloride and 4 moles of sucrose into 11 moles of water, the mole fraction of sodium chloride would be 0.25

$X(NaCl)=\frac{molesNaCl}{moles_{solution}} =\frac{5mol}{20mol} =0.25$

A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the solvent is water.

The solvent is the component in major proportion and the one that defines the state of the solution.

A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the solute is sodium chloride.

The solute is the component in minor proportion.

A way to express concentration that provides the moles of solute per liter of solution is molarity.

$M=\frac{n_{solute}}{V_{solution}(L)}$

3 0

3 years ago

An atom of lithium loses an electron. What is the effect of this event? Group of answer choices

Shalnov [3]

Answer:

option C= The atom of lithium becomes positively charged ion

Explanation:

When metals loses the electrons positive ions are formed. The nonmetals accept these electrons and form negative ions. These positive and negative ions attract each other through electrostatic force and form the bond called ionic bond.

Ionic bond:

Ionic bond is formed when oppositely charged ions attract each others i.e negative and positive ions.

We know that a neutral atom consist of equal number of proton and electron, cancel the charge of each other that is equal in magnitude and make the atom neutral or we can say that net charge is zero.

But when the atom lose or gain the electron, imbalance of neutron electron occur so charge will not remain zero and atom is no more to be said neutral.

Example:

Take the example of sodium that can lose one electron and form Na+. This Na+ ion is called cation because it carry positive charge by losing the one electron. This cation now contain eleven proton and ten electron.

Now consider the example of Chlorine atom. It consist of 17 proton and 17 electron. But in order to attain the noble gas configuration or to complete the octet it gain one electron and form anion (Cl-). The chlorine anion consist of 17 proton and 18 electron.

Now consider the compound formed by sodium and chlorine ions. Sodium chloride is an ionic compound. It is formed by the complete transfer of electron from sodium to chlorine atom and form ionic bond. In this ionic compound sodium carry positive charge and chlorine carry negative charge there is attraction between these oppositely charged atoms.

Na+ (cation)

Cl- (anion)

NaCl

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4 years ago

Why is water (H2O) considered the "universal solvent"?

Dmitriy789 [7]

It is considered as a universal solvent since most substances dissolve in water. And comparing it to other liquids, it is the one who dissolves a wide range of substances. Also, it is an important substance for every living thing.

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4 years ago