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3 years ago

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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If a gas furnace releases 420 kcal of heat energy, what is the energy in kilojoules? (1 cal = 4.184 J)

Igoryamba

Answer:
The furnace releases 1757280 J

Explanation:
We will do the conversion on two steps:
1- convert the kcal to cal
2- convert the cal to J

Step 1: converting kcal to cal
1 kcal is equivalent to 1000 cal. Therefore:
420 kcal is equivalent to 420*1000 = 420000 cal

Step 2: converting cal to J
We are given that:
<span>1 cal = 4.184 J
</span>Therefore:
420000 cal is equivalent to 420000 * 4.184 = 1757280 J

Hope this helps :)

8 0

3 years ago

How does urban sprawl affect water consumption?

Vesnalui [34]

Answer:

Urban sprawl is the development in urban areas

Due to which people are migrating from rural areas to urban areas to get the jobs or their income sources due to the opportunities.

So, as population is increasing in the urban areas. The food consumption and water consumption will also increase.

So, this is how urban sprawl affect water consumption.

5 0

3 years ago

Read 2 more answers

Is sulfur dioxide a compound, mixture or element? Thanks!

horsena [70]

It is a compound because a compound is two or more different elements chemically combined.

5 0

2 years ago

Match these items.

notka56 [123]

Litmus is an indicator
Charged particles are ions
Acids contain H+ ions
Bases contain OH - ions
Hydronium ions are H3O+

Now, I have to take issue with the last one
A base of pH 14 is not a strong base, it would be a highly concentrated base. A strong base is a base that completely deionizes in water.

But technically, for the purpose of your answer strong base = pH 14

6 0

3 years ago

2. Matt went to his friend’s party. He ate a big meal and drank a keg of beer. He felt heartburn after the meal and took Tums to

evablogger [386]

Answer:

390.85mL

Explanation:

Step 1:

Data obtained from the question.

Initial pressure (P1) = 780 torr

Initial volume (V1) = 400mL

Initial temperature (T1) = 40°C = 40°C + 273 = 313K

Final temperature (T2) = 25°C = 25°C + 273 = 298K

Final pressure (P2) = 1 atm = 760torr

Final volume (V2) =?

Step 2:

Determination of the final volume i.e the volume of the gas outside Matt's body.

The volume of the gas outside Matt's body can be obtained by using the general gas equation as shown below:

P1V1/T1 = P2V2/T2

780 x 400/313 = 760 x V2 /298

Cross multiply to express in linear form

313 x 760 x V2 = 780 x 400 x 298

Divide both side by 313 x 760

V2 = (780 x 400 x 298) /(313 x 760)

V2 = 390.85mL

Therefore, the volume of the gas outside Matt's body is 390.85mL

3 0

3 years ago