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garri49 [273]
3 years ago
5

Which one of the following statements BEST describes a chemical reaction?

Chemistry
1 answer:
Natalija [7]3 years ago
8 0

Answer: The correct statement is (A new substance is formed and the process can usually NOT be undone.)

Explanation:

A chemical reaction is simply defined as the reaction between two or more elements in which a new substance is formed and the process can usually not be undone. Different types of chemical reaction includes:

-- combination reaction: this occurs when two or more reactants form a product. For example: In the burning of coal, It combines with oxygen to produce carbon dioxide. Also in the burning of wood, carbon dioxide is given off and ashes are formed. Because new substance is being formed, they often can't be undone. The ashes formed can't be changed back into wood. Other types of chemical reaction are listed below.

-- Decomposition reaction

-- Single displacement reaction

-- Double displacement reaction

-- combustion reaction

-- Redox reaction

For the product of a chemical reaction to be undone (reversed), it has to undergo another chemical process different from the one that produced it.

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A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next fe
zubka84 [21]

Answer:

The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.

Explanation:

There will be a transfer of thermal energy (heat) from the hot metal plate to the surrounding air. This transfer of energy equates to a transfer of kinetic energy in the molecules. As the plate loses heat, the molecules in the plate will lose kinetic energy and slow down. As the surrounding air gains heat, the molecules will gain kinetic energy and speed up.

8 0
2 years ago
How many molecules are in 3 moles of potassium bromide (KBr)
sattari [20]

Answer:

Your strategy here will be to use the molar mass of potassium bromide,

KBr

, as a conversion factor to help you find the mass of three moles of this compound.

So, a compound's molar mass essentially tells you the mass of one mole of said compound. Now, let's assume that you only have a periodic table to work with here.

Potassium bromide is an ionic compound that is made up of potassium cations,

K

+

, and bromide anions,

Br

−

. Essentially, one formula unit of potassium bromide contains a potassium atom and a bromine atom.

Use the periodic table to find the molar masses of these two elements. You will find

For K:

M

M

=

39.0963 g mol

−

1

For Br:

M

M

=

79.904 g mol

−

1

To get the molar mass of one formula unit of potassium bromide, add the molar masses of the two elements

M

M KBr

=

39.0963 g mol

−

1

+

79.904 g mol

−

1

≈

119 g mol

−

So, if one mole of potassium bromide has a mas of

119 g

m it follows that three moles will have a mass of

3

moles KBr

⋅

molar mass of KBr



119 g

1

mole KBr

=

357 g

You should round this off to one sig fig, since that is how many sig figs you have for the number of moles of potassium bromide, but I'll leave it rounded to two sig figs

mass of 3 moles of KBr

=

∣

∣

∣

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

a

360 g

a

a

∣

∣

−−−−−−−−−

Explanation:

<em>a</em><em>n</em><em>s</em><em>w</em><em>e</em><em>r</em><em>:</em><em> </em><em>3</em><em>6</em><em>0</em><em> </em><em>g</em><em> </em>

6 0
3 years ago
The form of heat transfer taking place in the crust of the earth would be ____
Anna [14]
The form of heat transfer taking place in the crust of the Earth would be Convection.
7 0
3 years ago
Read 2 more answers
Question 2
Thepotemich [5.8K]

Answer:

1-Pentene

Explanation:

If we look at all the options listed, we will notice that the rate of reaction of bromine with each one differs significantly.

For 1-pentene, addition of bromine across the double bond is a relatively fast process. It is usually used as a test for unsaturation. Bromine water is easily decolorized by alkenes.

Cyclohexane, heptane are alkanes. They can only react with chlorine in the presence of sunlight. This is a substitution reaction. It does not occur easily. A certain quantum of light is required for the reaction to occur.

For benzene, bromine can only react with it by electrophilic substitution in which the benzene ring is retained. A Lewis acid is often required for the reaction to occur and it doesn't occur easily.

3 0
3 years ago
Ik i already asked this but i need diff point of views
salantis [7]

Answer:

Is it prescribe to you?If so than yes if not then no need to

Explanation:

5 0
3 years ago
Read 2 more answers
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