Question

what was the circumstance the narrator found strange about the signalman? Quote something that is said by narrator when he first met the signalman that foreshadowed the man's behaviour here
CLASS 8​

Answer 1

Explanation:

The reaction is MgCO

3

+CaCO

3

→MgO+CaO+2CO

2

.

1 mole of magnesium carbonate (molecular weight 84 g/mol) gives 1 mole of magnesium oxide (molecular weight is 40 g/mol).

Thus, 4.0 g of magnesium oxide is obtained from 8.4 g (0.1 mol) of magnesium carbonate.

Thus, in 18.4 g of mixture, 18.4−8.4=10 g (0.1 mol) of calcium carbonate (molecular weight =100 g/mole) is present.

A mixture of 1 mol of magnesium carbonate and 1 mole of calcium carbonate gives 2 moles of carbon dioxide.

Hence, a mixture of 0.1 mole of magnesium carbonate and 0.1 mole of calcium carbonate will give 0.2 moles of carbon dioxide.

At STP, 1 mole of carbon dioxide occupies 22.4 L.

Hence, 0.2 mole of carbon dioxide will occupy 0.2×22.4=4.48 L at STP.