Answer: The volume of 0.640 grams of 
gas at Standard Temperature and Pressure (STP) is 0.449 L.
Explanation:
Given: Mass of gas = 0.640 g
Pressure = 1.0 atm
Temperature = 273 K
As number of moles is the mass of substance divided by its molar mass.
So, moles of (molar mass = 32.0 g/mol) is as follows.
Now, ideal gas equation is used to calculate the volume as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
Thus, we can conclude that the volume of 0.640 grams of gas at Standard Temperature and Pressure (STP) is 0.449 L.
The answer is b. radon-222. The alpha decay means that it will emit an alpha particle when decays. The alpha particle has two protons and two neutrons. So Radium(88) minus two protons will become Radon(86). And the atomic mass will become 226-4=222.
Answer:
the mass of the glass is 2
Answer: Structural Isomers
Explanation:
The compounds having similar molecular formula but different arrangement of atoms or groups in space are called isomers and the phenomenon is called as isomerism.
Isomers are of two types: structural isomers and stereo isomers.
Structural isomers are isomers in which molecules with the same molecular formula have different bonding patterns.
Stereoisomers are isomers in which molecules have the same molecular formula and sequence of bonded atoms but differ in the three-dimensional orientations of their atoms in space.
Thus when molecules have the same number of each element but those atoms are arranged differently they are known as Structural isomers.
Atomic weight is actually calculated by the sum of protons and neutrons of that atom. It is not equal to the number. You must add them for the result
