Answer:
0.08 moles
Explanation:
Relative atomic mass of KMnO4 = K + Mn + O4 = 39 + 55 + 16 x 4 = 158
=> Moles in 13g of KMnO4 = 
= 
= 0.082278.. = 0.08 moles
Answer:
must have the same number of protons
T=20 min
m₀=200 g
t=60 min
the mass of element through time t is:
m=m₀*2^(-t/T)
m=200*2^(-60/20)=25 g
25 grams of element will be left after 60 minutes
Answer : The metal used was iron (the specific heat capacity is 
).
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.
where,
= specific heat of unknown metal = ?
= specific heat of water = 
= mass of unknown metal = 150 g
= mass of water = 200 g
= final temperature of water = 
= initial temperature of unknown metal = 
= initial temperature of water = 
Now put all the given values in the above formula, we get
Form the value of specific heat of unknown metal, we conclude that the metal used in this was iron (Fe).
Therefore, the metal used was iron (the specific heat capacity is ).
Answer: Option (E) is the correct answer.
Explanation:
Since, the conductor is hollow which means that it is opened on both the ends. Hence, when a small uncharged metal ball is passed through it with the help of a silk thread then due to the presence of this insulating thread the ball will not come directly in contact with the charged rod.
As a result, there will occur no formation of opposite charge on the metal ball. Therefore, the ball will remain uncharged in nature.
Thus, we can conclude that after the given ball is removed, it will have no appreciable charge.
