<span>There are only three stereoisomers of 1,2-dimethylcyclopentane. As there are only two chiral carbons, so the maximum number of stereoisomers is 4, but two are the same meso-compound which means that there are only 3.</span>
        
             
        
        
        
The mass of hydrogen gas is 1.00794 u ± 0.00001 u.  I hope this helps you out!!
        
             
        
        
        
Answer:
Q = 450 J
Explanation:
Given that,
Mass of a piece of glass, m = 45 g
The temperature changes from 10°C to 30°C. 
The specific heat is 0.5 J/g°C
We need to find heat required to raise the temperature. The formula that is used to find it is given by :

So, the required heat is 450 J. Hence, the correct option is (c).