Please help me with number 4

Which process is endothermic?a)b)c)d)The evaporation of water from the skin.The burning of candle wax.The oxidation of iron in a

BlackZzzverrR [31]

Answer:

The answer is option a. The evaporation of water from the skin

Explanation:

An endothermic reaction is any synthetic reaction that retains heat from its environment. The ingested energy gives the enactment energy to the reaction to happen.

No new bonds formed, no bonds broken in this example. water molecules go from liquid to vapour (gas ), intermolecular bond exist between polar (-OH) molecules and energy is required to break these bonds during the change from liquid to gas. So, it is endothermic .

Remaining three above examples are exothermic. combustion of gas releases energy(exothermic). burninig of the candle exothermic because the energy released from the oxygen into carbon dioxide and water.oxidation of iron also exothermic

6 0

2 years ago

Why cant h2o delirious marry me

Likurg_2 [28]

What do you mean is that a school question

7 0

3 years ago

Read 2 more answers

120 grams of calcium nitrite Ca(NO2)2 is dissolved in a 240 mL solution. What is the molarity of the solution???

expeople1 [14]

Hey there!:

Molar mass Ca(NO2)2 = 132.089 g/mol

Mass of solute = 120 g

Number of moles:

n = mass of solute / molar mass

n = 120 / 132.089

n = 0.0009084 moles of Ca(NO2)2

Volume in liters of solution :

240 mL / 1000 => 0.24 L

Therefore:

Molarity = number of moles / volume of solution

Molarity = 0.0009084 / 0.24

Molarity = 0.003785 M

Hope that helps!

5 0

3 years ago

Five gases combined in a gas cylinder have the following partial pressures: 3. 00 atm (N2), 1. 80 atm (O2), 0. 29 atm (Ar), 0. 1

Helen [10]

The total pressure of the gaseous mixture has been 5.37 atm. Thus, option D is correct.

The partial pressure has been defined as the pressure exerted by each gas in the mixture.

According to the Dalton's law of partial pressure, the total pressure of gas has been the sum of the partial pressure of the gases in the mixture.

The given partial pressure of gases in the mixture has been:

Partial pressure of Nitrogen, $P_N_2=3\;\rm atm$
Partial pressure of Oxygen, $P_O_2=1.80\;\rm atm$
Partial pressure of Argon, $P_A_r=0.29\;\rm atm$
Partial pressure of Helium, $P_H_e=0.18\;\rm atm$
Partial pressure of Hydrogen, $P_H=0.10\;\rm atm$

The total pressure of the gaseous mixture has been:

$P=P_N_2\;+\;P_O_2\;+\;P_A_R\;+\;P_H_e\;+\;P_H\\P=3\;+\;1.80\;+\;0.29\;+\;0.18\;+\;0.10\;\text {atm}\\P=5.37\;\rm atm$

The total pressure of the gaseous mixture has been 5.37 atm. Thus, option D is correct.

For more information about partial pressure, refer to the link:

brainly.com/question/14623719

7 0

1 year ago

Would you predict that the C−O bond lengths in the formate ion would be longer or shorter relative to those in CO2?

ivolga24 [154]

The Lewis structures for formate ion and carbon dioxide are shown in the attached pictures. As you can see, the formate ion consists of one C=O bond and one C-O bond, while carbon dioxide has two C=O bonds. Double bonds are weaker, hence, longer compared to single bonds. Therefore, the C-O bonds in the formate ion is shorter than those in carbon dioxide.

3 0

2 years ago