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marysya [2.9K]
3 years ago
11

A compact disc has a diameter of 11.8 cm. What is the surface area of the disk in square centimeters? In square meters?

Chemistry
1 answer:
Leona [35]3 years ago
5 0
A disc is a circle so the formula for the area is pie r^2. So plugging in the numbers bring in the answer of 18.53
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Compared to the sun , all of the stars that can be observed in the night sky are?
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How many moles of magnesium oxide are there in 2.50* 10^25 formula units of MgO?
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I wanted known how many of the reaction below is energy released
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The given reaction is formation of water. In this reaction oxygen and hydrogen react to form water and 486 kj/mol is also released.

The reaction in which heat is released is called exothermic reaction.

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

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it can be written as,

C + O₂   →  CO₂ + 393 Kj/mol

Endothermic reactions:

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In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O   →  CO  + H₂

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it can be written as,

C +  H₂O  + 131 kj/mol  →  CO  + H₂

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