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3 years ago

Based on their descriptions, classify these chemical changes as endothermic or exothermic.

Chemistry

2 answers:

Arlecino [84]3 years ago

4 0

Answer: 1) endothermic

2) exothermic

3) exothermic

4) exothermic

5) endothermic

Explanation: An endothermic reaction is a type of of chemical reaction in which energy is absorbed from the surrounding. The temperature of the surrounding decreases.

An Exothermic reaction is a type of of chemical reaction in which energy is released into the surrounding. The temperature of the surrounding increases.

1) A chemical change takes place in a container, making it feel cold to touch: When an endothermic reaction takes place in the container, the temperature of the surrounding (here the outside wall of the container) will decrease which can be felt by touching the outside of the container.

2) Burning wood: Burning of wood is an example of exothermic reaction because energy is releases into surroundings.

3) A chemical change takes place in a container, making it feel hot to touch : When an exothermic reaction takes place in the container, the temperature of the surrounding (here the outside wall of the container) will increase which can be felt by touching the outside of the container.

4) Pocket hand warmers(used by skiers) start out at room temperature. When you open the air tight packaging, a substance reacts with air, and it quickly begins to feel hot: When an exothermic reaction takes place in the container, the temperature of the surrounding (here the outside wall of the hand warmer) will increase which can be felt by touching the outside of the warmer.

5) A "cold pack" (used for sport injuries) starts out a room temperature. But when you squish the liquid around, you cause two substances to mix that were originally kept separate. Those substances react and the pack begins to feel cold: When an endothermic reaction takes place in the cold pack, the temperature of the pack will decrease which can be felt by touching the outside of the pack.

Pavlova-9 [17]3 years ago

3 0

_Award brainliest if helped!
1. Endothermic
2. Exothermic
3. Exothermic
4. Exothermic
5. Endothermic

(Endothermic absorbs energy (heat) from the surrounding making surrounding cooler, and vice versa for exothermic.)

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Study the Lewis dot diagram for nitrogen. Explain what is correct and what is incorrect about the diagram. Use details to suppor

Verdich [7]

Answer:

The Lewis dot diagram is supposed to have dots on each side. What's incorrect is that there isn't a dot on the bottom, only the left and right side and the top. What's correct about this is that there are 5 outer valence electrons, and they correctly put 5 dots, even though they're in the wrong place.

Explanation:

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3 years ago

How many molecules are in 25.8 moles of Co2

kompoz [17]

<h3>Answer:</h3>

1.55 × 10²⁵ Molecules

<h3>Explanation:</h3>

We are given;

Moles of CO₂ = 25.8 moles

We are required to calculate the molecules of CO₂

We are going to use the Avogadro's constant, 6.022× 10²³,

Such that 1 mole of a compound contains 6.022× 10²³ molecules

Thus;

1 mole of CO₂ contains 6.022× 10²³ molecules

Hence,

25.8 moles will contain;

= 25.8 moles × 6.022× 10²³ molecules/mole

= 1.5537 × 10²⁵ Molecules

= 1.55 × 10²⁵ Molecules

Thus, 25.8 moles of CO₂ contains 1.55 × 10²⁵ Molecules

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3 years ago

Is silicon a better conductor of electricity than sulfur

astra-53 [7]

Answer:

Silicon is a better conductor of electricity than sulfur. ... Silicon is a solid at room temperature, but argon is a gas. Silicon is less malleable than silver.

Explanation:

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3 years ago

Activity A moles need hlp

damaskus [11]

I would always start by balancing your carbons, and then balancing the rest from there.

1. C2H5OH + O2 —> CO2 + H2O - You have two carbons on the left and one on the right. Multiply CO2 by 2.
C2H5OH + O2 —> 2CO2 + H2O

Now balance hydrogen. You have 6 on the left and 2 on the right. Multiply H2O by 3.
C2H5OH + O2 —> 2CO2 + 3H2O

Now balance oxygen. You have 3 on the left and 7 on the right. You need 4 more on the left. Don’t multiply the C2H5OH by anything because that will change the numbers of everything else too. Multiply O2 by 3 instead.
C2H5OH + 3O2 —> 2CO2 + 3H2O

Check that all atoms are now balanced, and you’re good.

2. Same process as before.

First carbons - C3H8 + O2 —> 3CO2 + H2O
Then hydrogens - C3H8 + O2 —> 3CO2 + 4H2O
Then oxygens - C3H8 + 5O2 —> 3CO2 + 4H2O

3. Same again.

Carbons) C6H12O6 + O2 —> 6CO2 + H2O
Hydrogens) C6H12O6 + O2 —> 6CO2 + 6H2O
Oxygens) C6H12O6 + 6O2 —> 6CO2 + 6H2O

4. The general reaction for a combustion reaction is a hydrocarbon reacting with oxygen to produce carbon dioxide and water.

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3 years ago

Will give brainliest, like, 5 stars and 5 points to best answer

Oliga [24]

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3 years ago