This problem is providing us with the chemical equation for the decomposition of water to hydrogen and oxygen, the involved bond energies and asks for the total energy of the reaction as well as whether it is endothermic or exothermic. At the end, one comes to the conclusion that it is exothermic because the total energy is -425 kJ.
<h3>Bond energy:</h3>
In chemistry, bond energies are defined as the necessary energy to break a bond between two atoms. In this case, we see that water, H2O has two H-O bonds and hydrogen and oxygen have two H-H and one O=O bonds, respectively.
Thus, we write the following heat equation, which comprises the aforementioned bond energies and the stoichiometric coefficients in the reaction:
Hence, we plug in the given bond energies to obtain:
Where the negative suggests this is an exothermic reaction as it releases energy (negative enthalpy).
Learn more about bond energies: brainly.com/question/26141360
A low pressure system has lower pressure at its center than the areas around it. Winds blow towards the low pressure, and the air rises in the atmosphere where they meet. As the air rises, the water vapor within it condenses, forming clouds and often precipitation.
<u>Explanation</u>:
- Wind flow towards the low pressure and the air rises in the atmosphere. As the air increases, the water vapor within it solidifies, forming clouds and undergo precipitation. Low pressure formed in the center areas.
- The atmospheric circulations of air up and down in a low-pressure area remove a small amount of atmosphere. This usually happens between warm and cold air masses by flowing air which tries to reduce the contrast of temperature.
Answer:
<u>7.44 grams CaCl2 will produce 10.0 grams KCl.</u>
Explanation:
The equation is balanced:
I've repeated it here, with the elements corrected for their initial capital letter.
CaCl2( aq) K2CO3( aq) → 2KCl( aq) CaCO3( aq)
This equation tells us that 1 mole of CaCl2 will produce 2 moles of KCl.
If we want 10.0g of KCl, we need to convert that mass into moles KCl by dividing by the molar mass of KCl, which is 74.55 grams/mole.
(10.0 grams KCl)/(74.55 grams/mole) = 0.1341 moles of KCl.
We know that we'll need half that amount of moles CaCl2, since the balanced equation says we'll get twice the moles KCl for every one mole CaCl2.
So we'll need (0.1341 moles KCl)*(1 mole CaCl2/2moles KCl) = 0.0671 moles CaCl2.
The molar mass of CaCl2 is 110.98 grams/mole.
(0.0671 moles CaCl2)*(110.98 grams/mole) = 7.44 grams CaCl2
<u>7.44 grams CaCl2 will produce 10.0 grams KCl.</u>
