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SSSSS [86.1K]
3 years ago
10

How and why are Endothermic and Exothermic reactions chemical changes?

Chemistry
1 answer:
Olin [163]3 years ago
8 0

Answer:

Chemical reactions often involve changes in energy due to the breaking and formation of bonds. Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic.

Explanation:

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stepladder [879]
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We can see water change state, from ice to steam. This is a __________ change in matter. A) chemical B) combustion Eliminate C)
Gemiola [76]

Answer: Option (C) is the correct answer.

Explanation:

When chemical composition of a substance is not changing in a chemical reaction then it is known as a physical change.

For example, when water change state, from ice to steam then it means solid state is changing into gaseous state.

Therefore, it is a physical change.

And, a reaction which causes change in chemical composition is known as a chemical change.

For example, Li + Cl \rightarrow LiCl

Thus, we can conclude that we can see water change state, from ice to steam. This is a physical change in matter.

4 0
3 years ago
Larger charges or shorter distances result in greater electric<br> force.<br> TRUE<br> FALSE
Nimfa-mama [501]

Answer:

The strength of electric force depends on the amount of electric charge on the particles and the distance between them. Larger charges or shorter distances result in greater force.

Explanation:

5 0
3 years ago
How many atoms are in 13.97 liters of water vapor at STP
Arisa [49]
<span>Let's </span>assume that water vapor has ideal gas behavior. <span>
Then we can use ideal gas formula,
PV = nRT<span>

</span><span>Where, P is the pressure of the gas (Pa), V is the volume of the gas (m³), n is the number of moles of gas (mol), R is the universal gas constant ( 8.314 J mol</span></span>⁻¹ K⁻¹) and T is temperature in Kelvin.<span>
<span>
</span>P = 1 atm = 101325 Pa (standard pressure)
V = 13.97 L = 13.97 x 10</span>⁻³ m³<span>
n = ?
R = 8.314 J mol</span>⁻¹ K⁻¹<span>
T = 0 °C = 273 K (standard temperature)
<span>
By substitution,
</span>101325 Pa x 13.97x 10</span>⁻³ m³ = n x 8.314 J mol⁻¹ K⁻¹ x 273 K<span>
                                          n = 0.624 mol
<span>
Hence, the moles of water vapor at STP is 0.624 mol.

According to the </span></span>Avogadro's constant, 1 mole of substance has 6.022 × 10²³ particles.
<span>
Hence, number of atoms in water vapor = 0.624 mol x </span>6.022 × 10²³ mol⁻¹
<span>                                                                = 3.758 x 10</span>²³<span>

</span>
5 0
3 years ago
Hersey chocolate company makes 80 million kisses daily how many chocolate kisses are made per second
Scrat [10]

Answer:

92.5925925926

Explanation:

8 million divided by the seconds in a day witch is 86400

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