Answer: option A.
A physical change occurred in which the iron remained iron, but lost one of its physical properties
Explanation: magnetization and demagnetization is a physical change as no new substance is form and it is easily reversed. When an iron rod is magnetized, it can loss it magnetic property by hitting it. So when an iron rod which is magnetized falls from a height it can also loss its magnetic property
Answer:
0.21mol Ar (g)
Explanation:
To convert from litres to moles at STP we must divide the amount of litres by 22.4.
4.7 / 22.4 = 0.21mol Ar (g)
The number of moles in monochloro pentaborane (9)
is 0.37056.
We know that ,
Number of moles = Given mass/ Molar mass
Given mass of monochloro pentaborane (9) is 20.1 g
The molar mass of monochloro pentaborane (9) is
= 
= 
= 54.241
Thus number of moles = 20.1/54.241
= 0.37056
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Answer:
I believe the answer is C