4 g of calcium is burnt with 2.4 g O2 in a closed vessel. Which reacta

1.	4 g of calcium is burnt with 2.4 g O2 in a closed vessel. Which reactant is left and how much?
Answer» Answer: oxygen is left by 0.8 grams Explanation: in reaction of calcium and oxygen 2Ca + O2 ----> 2CaO for 80 grams of calcium ( 2 mole mass of calcium = 80) it requires 32 GM of oxygen now for 4 grams it requires just 1.6 gm of oxygen (since 4 = 80/20 1.6 = 32/20) but here is oxygen is PRESENT in excess( i.e more than 1.6) hence after TOTAL reaction 2.4-1.6 gm of oxygen is left . . . 0.8 gm of oxygen is left

4 g of calcium is burnt with 2.4 g O2 in a closed vessel. Which reactant is left and how much?

Answer»

Answer:

oxygen is left by 0.8 grams

Explanation:

in reaction of calcium and oxygen

2Ca + O2 ----> 2CaO

for 80 grams of calcium ( 2 mole mass of calcium = 80) it requires 32 GM of oxygen

now for 4 grams it requires just 1.6 gm of oxygen (since 4 = 80/20 1.6 = 32/20)

but here is oxygen is PRESENT in excess( i.e more than 1.6)

hence after TOTAL reaction 2.4-1.6 gm of oxygen is left

. . 0.8 gm of oxygen is left