The answer would be A) Physical Change. When the silver tarnishes it is still remnants of silver. If it were B, the silver would change into a different substance.
To determine the amount of oxygen that is present in the compound, we have to assume that the given compound contains carbon, hydrogen and oxygen only or else we will not be able to determine the answer. We need to convert the moles of the elements given to units of grams by using the atomic mass of these elements. Then, from the total amount of the compound we subtract the masses of the elements. We do as follows:
mass
0.117 mol C ( 12.01 g / 1 mol ) = 1.41 g
0.233 mol H ( 1.01 g / 1 mol ) = 0.24 g
Mass O = 3.50 g - 1.41 g - 0.24 g = 1.85 g O
Moles O = 1.85 g O ( 1 mol / 16 g ) = 0.116 moles O
Answer:
d is the right one. aaßriadjcjfjfjfdjfjf
polyethylene contains HC=CH units.
mass of this is 26 gram/mol
number of such units =13500/26
