Answer:
The reaction is exothermic (option 4)
Explanation:
P4 + 5O2 → P4O10 + 712 kcal
In chemical reactions heat can be absorbed or released:
⇒in the first case, when heat is absorbed, this is called an endothermic reaction. The products have more energy than the reactants. The reaction requires or absorbs energy from it's surroundings. That means that in this reaction energy , in the form of heat, will be absorbed by the reactants.
⇒ when heat is released, this is called an exothermic reaction. The reactants have more energy than the products. The reaction gives or releases energy to it's surroundings. That means that in this reaction energy , in the form of heat, will be released by the reactants.
in the case of P4 + 5O2 → P4O10 + 712 kcal
We notice that on the right side, which is the product side, there is a positive amount of energy. This means that the energy is released by the the reactants, in this reaction. <u>The reaction is exothermic.</u>
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First, we apply the law of conservation of mass which states that the total mass in a system remains constant.
Therefore, there must be 5.00 g of sulfur and 4.99 g of oxygen in the product. Now, we determine the mass percentage using:
Mass % = (mass of sulfur x 100) / total mass of compound
Mass % = (5 * 100) / (5 + 4.99)
Mass % = 50.05%
The product contains 50.05% sulfur by mass.
Answer:
Explanation:
C + O2 → CO2
Mole of C = 24 g/(12 g/mole)
Mole of C = 2 mole
Mole of molecular O2 = 74 g/(32 g/mole)
Mole of molecular O2 = 2.3125 mole
Since mole of C < mole of O2, then C being the limiting reagent.
From the reaction, it shows that mole ratio between C and O2 = 1 : 1.
So, 2 moles of C will stoichiometrically react with 2 moles of O2 to generate 2 moles of CO2.
Avogadro's law states that :"equal volumes of all gases, at the same temperature and pressure, have the same number of molecules i.e. 6.02 x 10^23 molecules/mole.
Therefore, 2 moles of CO2 contain 2 moles x 6.02 x 10^23 molecules/mole = 1.204 x 10^24 molecules of CO2 is formed.