What does a catalyst do when added to a chemical reaction? Select all that apply.

Chemistry

2 answers:

Darina [25.2K]3 years ago

8 0

Answer:

$\boxed {\boxed {\sf It \ lowers \ the \ activation \ energy \ and \ it \ speeds \ up \ chemical \ reactions }}$

Explanation:

A catalyst is a substance that increases the rate of a chemical reaction. Some examples are enzymes and acid-base catalysts.

They can do this by lowering activation energy (the energy needed to undergo a reaction) or modifying a certain mechanism in the reaction.

Catalysts are unique because they aren't consumed or used up in a reaction. They can be reused many times.

So, based on the information above, catalysts do not increase the activation energy or get consumed in the reaction. That leaves two correct answers: they lower the activation energy and speed up chemical reactions.

Stels [109]3 years ago

7 0

Answer:

It increases the activation energy.

It speeds up chemical reactions.

Explanation:

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Atoms of arsenic (As) are often added to silicon (Si) in a process called doping to change the conductivity of the silicon. How

Basile [38]

Answer:

B.) An atom of arsenic has one more valence electron and more electron shells than an atom of silicon, so the conductivity decreases because the arsenic atom loses the electron.

Explanation:

Silicon is located in the 3rd row and 14th column in the periodic table. Arsenic is located in the 4th row and 15th column in the periodic table. This means that arsenic has one more valence electron than silicon. Since arsenic is located one row down from silicon, its valence electrons occupy higher energy orbitals.

Silicon maintains a crystal-like lattice structure. Each silicon atom is covalently connected to assume this shape. When silicon gains one extra electron from arsenic, it experiences n-type doping. This new electron is not tightly bound in the lattice structure. This allows it to move more freely and conduct more electricity. This can also be explained using band gaps. Silicon, which previously had an empty conduction band, now has one electron in this band. This lowers the band gap between the conduction and valence bands and increases conductivity.

5 0

2 years ago

Which pair of reactants will undergo aldol condensation to produce methylvinyl ketone?

xenn [34]

When formaldehyde and acetone then react with each other( aldol condensation) then it will be formed methyl vinyl ketone.

In organic chemistry, an aldol condensation would be a condensation reaction in which an enol and enolate ion combines with a carbonyl chemical to produce a -hydroxy aldehyde or -hydroxy ketone, that is then dehydrated to produce a conjugated enone.

In aldol condensation, when formaldehyde and acetone then react with each other then it will be formed methyl vinyl ketone.

It can be written as

$CH_{2} O + CH_{3} COCH_{3}$ → $HOCH_{2} -CH_{2} -CO-CH_{3}$