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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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Step2247 [10]

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8 0

3 years ago

A sodium hydroxide solution is made by mixing 8.70 g NaOH with 100 g of water. The resulting solution has a density of 1.087 g/m

Ahat [919]

Answer:

Mass fraction = 0.08004

Mole fraction = 0.0377

Explanation:

Given, Mass of NaOH = 8.70 g

Mass of solution = 8.70 + 100 g = 108.70 g

$Mass\ fraction\ of\ NaOH=\frac {8.70}{108.70}$ = 0.08004

Molar mass of NaOH = 39.997 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{8.70\ g}{39.997\ g/mol}$

$Moles\ of\ NaOH= 0.2175\ mol$

Given, Mass of water = 100 g

Molar mass of water = 18.0153 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{100\ g}{18.0153\ g/mol}$

$Moles\ of\ water= 5.5508\ mol$

So, according to definition of mole fraction:

$Mole\ fraction\ of\ NaOH=\frac {n_{NaOH}}{n_{NaOH}+n_{water}}$

$Mole\ fraction\ of\ NaOH=\frac {0.2175}{0.2175+5.5508}=0.0377$

3 0

3 years ago

Hydrophobic compounds dissolve in

Anastaziya [24]

Hydrophobic molecules tend to be nonpolar molecules that group together to form micelles rather than be exposed to water. Hydrophobic molecules typically dissolve in nonpolar solvents (e.g., organic solvents).

4 0

3 years ago

This substance consists of two or more different elements chemically combined

kow [346]

The substance would be referred to as a compound substance.

8 0

3 years ago

Which models of the atom include a structure that is mostly made of empty space?RutherfordThomsonBohrQuantum mechanical

Luba_88 [7]

<h2>Answer:</h2>

Rutherford's models

<h2>Explanations:</h2><h2>What is the electron cloud model?</h2>

There are known as the region where electrons are found especially in the nucleus.

According to the five basic atomic models which have contributed to the structure of the atom itself, the Rutherford's models of the atom include a structure that is mostly made of empty space compared to thomson that proposed the plum pudding model of the atom

4 0

1 year ago