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3 years ago

Which process is exothermic?

Chemistry

2 answers:

Sav [38]3 years ago

5 0

Answer: c. condensation of ethanol vapor

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.

a.boiling of water: This involves conversion of liquid to gas and thus require energy and is endothermic.

b.melting of copper: This involves conversion of solid to liquid and thus require energy and is endothermic.

c. condensation of ethanol vapor: This involves conversion of vapor to liquid and thus release energy and is exothermic.

d.sublimation of iodine: This involves conversion of solid to gas and thus require energy and is endothermic.

valkas [14]3 years ago

4 0

The exothermic process is a process or reaction that involves a release of energy from the system to its surroundings in various forms usually through heat, light, electricity or sound. In the four given choices, when melting a copper, you try to immerse the metal in heaping coals of fire. The metal will absorb the thermal energy coming from the coal, thus, once you retrieve the metal back, light will be emitted from it as well as heat.

Therefore, the answer is B. MELTING OF COPPER

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Calculate the mass of CO2 that can be produced if the reaction of 54.0 g of propane and sufficient oxygen has a 64.0% yield.

Oduvanchick [21]

Answer:

103.9 g

Explanation:

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

First we convert 54.0 g of propane (C₃H₈) into moles, using its molar mass:

54.0 g ÷ 44 g/mol = 1.23 mol C₃H₈

Then we convert 1.23 moles of C₃H₈ into moles of CO₂, using the stoichiometric coefficients:

1.23 mol C₃H₈ * $\frac{3molCO_2}{1molC_3H_8}$ = 3.69 mol CO₂

We convert 3.69 moles of CO₂ into grams, using its molar mass:

3.69 mol CO₂ * 44 g/mol = 162.36 g

And apply the given yield:

162.36 g * 64.0/100 = 103.9 g

7 0

3 years ago

A sample of a certain material has a mass of 2.03 × 10–3 g. Calculate the volume of the sample, given that the density is 9.133

liq [111]

2.22x10^-3 would be the answer to the question
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3 years ago

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Why is it important to use low flame when evaporating water from a recovered filtrate?

goldfiish [28.3K]

It is important to use low flame when evaporating water from a recovered filtrate because then the water and filtrate will not spatter and the filtrate can also be recovered after evaporating water.

If flame is not low then water as well as got spatter so it is important to use low flame so that the water and filtrate will not spatter.

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3 years ago

The first excited vibrational energy level of diatomic chlo- rine (Cl2) is 558 cm^-1 above the ground state. Wave- numbers, the

Usimov [2.4K]

Answer:

The answer is "0.0000190 and 2.7 J".

Explanation:

$\to P_4=\frac{e^{-\beta}(4+\frac{1}{2}) hev}{2vb}\\\\$

$=\frac{e^{-9(1.35)}}{0.278v}\\\\=\frac{e^{-12.5}}{0.278}\\\\=\frac{0.000005285}{0.278}\\\\=0.0000190$

Given:

$h=6.626 \times 10^{-34}\\\\c=3\times 10^{10}\\\\v=558\ cm^{-1}\\\\K=1.38 \times 10^{-23}\\\\ T=298\\\\$

$E=\frac{hcv}{KT}\\\\$

by putting the value into the above formula so, the value is 2.7 J

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3 years ago

Can a chemical reaction happen with only one substance? For example, if you select water as the first substance but you don't ad

KATRIN_1 [288]

Explanation:

Yes, a chemical reaction can happen with only one substance.

A typical example of such reaction is the radioactive decay.

Radioactive decay is the loss of elementary particles from an unstable nucleus, ultimately changing the unstable element into another more stable element. .

When radioactive elements are let alone, they decompose to form stable harmless elements.

An example of radioactive decay is attached in the image below;

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3 years ago

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