Answer:
A supersaturated solution made out of sugar and oil is crystallized on a surface suitable for crystal nucleation such as a stick.
I hope this helps.
Sound is made when air molecules. Vibrate and move in a wave pattern, so sound moves in waves of compressions and refractions (expansion).
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<u>Answer:</u> The formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.
<u>Explanation:</u>
To calculate the number of moles, we use the equation:

Given mass of oxygen gas = 83 g
Molar mass of oxygen gas = 32 g/mol
Putting values in above equation, we get:

For the given chemical equation:

<u>Sign convention of heat:</u>
When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.
By Stoichiometry of the reaction:
When 3 moles of oxygen gas is formed, the amount of heat absorbed is 824.2 kJ
So, when 2.594 moles of oxygen gas is formed, the amount of heat absorbed will be = 
Hence, the formation of given amount of oxygen gas results in the absorption of 713 kJ of heat.
I believe it would be the last one because you can use the molar mass of HCl to find the number of moles, then use Avogadro’s number to find the number of atoms
Hope this helps!
Sugar burns and turns black. A completely new substance was formed, which is the main pointer for it being a chemical reaction. More evidence would be change of color, odor, and the fact that flammability is a chemical property so setting something on fire would be a chemical change.