1

IIT-JEE 1994

Fill in the Blanks
The compound YBa2Cu3O7, which shows superconductivity, has copper in oxidation state ______ assume that the rare earth element yttrium is in its usual +3 oxidation state.

Answer

$$ + {7 \over 3}$$
2

IIT-JEE 1991

Fill in the Blanks
The weight of $$1 \times 10^{22}$$ molecules of CuSO4.5H2O is ____.

Answer

4.14 g
3

IIT-JEE 1983

Fill in the Blanks
3 g of a salt of molecular weight 30 is dissolved in 250 g of water. The molality if the solution is _____.

Answer

0.4m
4

IIT-JEE 1980

Fill in the Blanks
The total no of electron present in 18 ml of water is ______.

Answer

$$6.02 \times 10^{24}$$

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