739 is the number of atoms of O in 92.3 moles of Cr3(PO4)2.
Explanation:
Molecular formula given is = Cr3(PO4)2
number of moles of the compound is 92.3 moles
number of 0 atoms in 92.3 moles =?
From the chemical formula 1 mole of the compound has 8 atoms of oxygen
So, it can be written as
1 mole Cr3(PO4)2 has 8 atoms of oxygen
92.3 moles of Cr3(PO4)2 has x atoms of oxygen
= 
x = 8 x 92.3
x = 738.4 atoms
There will be 739 oxygen atoms in the 92.3 moles of Cr3(PO4)2.
81. There is 1 carbon, 2 chlorine and fluorine atoms in Freon 12. To draw them it forms a cross with C in the middle and Cl and F both on the opposite side.
Cl
l
F - C- F
l
Cl
82. Freon-12 and Freon-14 are called halocarbons or just halides.
Answer: In an open system the vapor pressure is equal to the outside air pressure.
Explanation:
An open system is a system that is capable of exchanging both matter and energy with its surroundings.
For example, a hot cup of coffee is an open system as the cup is not covered with a lid. Therefore, heat energy from the coffee goes into the surroundings.
Vapor pressure is defined as the ability of a substance to change into vapor state. pressure
Therefore, we can conclude that in an open system the vapor pressure is equal to the outside air pressure.
Answer:
heat energy
Explanation:
Chemical reactions often involve changes in energy due to the breaking and formation of bonds. Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic.
