A 13.8 g sample of X reacts with a sample of Y to form 68.3 g of XY. What is the mass of Y that reacted

54.5 grams of Y reacted with 13.8 g sample of X to form 68.3 g of XY.

Explanation:

In chemical reaction the mass remains conserved until the dissipation or lost is shown. In the question it is mentioned that 13.gm of X reacts with some amount of Y to form a product XY of mass 68.3 grams.

The reaction given is addition reaction in which two elements react to for a compound.

X + Y ⇒ XY

So, in the chemical reaction value of mass is put as

13.8 + Y = 68.3

Y = 68.3-13.8

Y   = 54.5 grams

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

that tool would be a compass