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jolli1 [7]
3 years ago
7

Pls i need help with this

Chemistry
1 answer:
gregori [183]3 years ago
5 0

Answer:

C

Explanation:

A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.

A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.

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PLEASE HELP- CHEMISTRY QUIZ
jonny [76]

Answer:

•Li2S is at a low melting point

•NCL3 is a covalent bond

Explanation:

Just some notes to help you:))

Covalent Bonds: A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons

5 0
3 years ago
Draw the conjugate base for the Brønsted-Lowry acid-base reaction that occurs when the following acid reacts with water. Show al
DanielleElmas [232]

Answer:

The structures are shown below.

Explanation:

When the acid reacts with water, it loses one proton (H⁺) and forms a base, which is the conjugate base of its acid.

The formal charge of an atom can be calculated by:

FC = X - (Y + Z/2)

Where X is the valence electrons of the neutral atom, Y is the unshared electrons, and Z is the shared electrons in the molecule.

a) When HCl deprotonates, it forms Cl⁻ as the conjugate base. The neutral atom Cl has 7 valence electrons (X), the ion has 8 unshared electrons (Y) and none shared electrons, so FC = -1 The structure is shown below in figure a.

b) When Hbr deprotonates it forms Br- as the conjugate base. The neutral atom has 7 valence electrons (X), the ion has 8 unshared electrons (Y) and none shared electrons, so FC = -1. The structure is shown below in figure b.

c) When CH3COOH loses a proton, it forms the conjugate base CH3COO⁻. The carbon as 4 valence electrons, hydrogen has 1 valence electron and oxygen has 6 valence electrons. The first carbon make simple bonds with each hydrogen and with the second carbon, and so, all the electrons are shared, and it has FC = 4 - (0 + 8/2) = 0, as so the hydrogens have FC = 1 - (0 + 2/2) = 0.

The second carbon does 1 simple bond with the first carbon, a double bond with one oxygen, and a simple bond with the other oxygen, and so doesn't have unshared electrons, and FC = 4 - (0 + 8/2) = 0.

The first oxygen does a double bond with the carbon, and so it has 4 unshared electrons, so FC = 6 - (4 + 4/2) = 0. The second oxygen does a simple bond with the carbon, and so has 5 unshared electrons, so FC = 6 - (5 + 2/2) = 0.

The structure is shown in figure c.

7 0
3 years ago
Read 2 more answers
Acetonitrile major species present when dissolved in water
IrinaVladis [17]

Acetonitrile refers to the chemical compound exhibiting the formula CH₃CN. It is the basic organic nitrile and a colorless liquid. It is generated primarily as a byproduct of acrylonitrile production. It is used as a polar aprotic solvent in the purification of butadiene and in organic synthesis.  

The addition of water to cyanides generates amines and acids. Acetonitrile produces ammonia and acetic acid.  

CH₃CN (acetonitrile) → CH₃COOH (acetic acid) + NH₃ (ammonia)


3 0
3 years ago
If you need to measure the mass of a greeting card you are sending to a friend through the mail, what unit of measurement would
erica [24]
You would use grams to measure ot
4 0
3 years ago
A 1.3 g sample of a substance is heated from 0°C to 45°C and is found to have absorbed 45 j of heat. What is the specific heat o
wlad13 [49]

Q=mcat

45=(1.3)(c)(45)

45=58.5c

.769=c

~.77

The answer is .77

5 0
3 years ago
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