Question

(a)Write the molecular formula of calcium phosphate and magnesium nitride (1) (b) What are polyatomic ions? Write one example of a positively charged polyatomic ion (1) (c )When 3gms of carbon is burnt in 8 gm oxygen . 11gm of carbon dioxide is formed. What mass of carbon dioxide will be formed when 3 gm of carbon is burnt in 50gm of oxygen? (1)
​

Answer 1

Answer:

(a)molecular formula for calcium phosphate is Ca3(PO4)2.

magnesium nitride-Mg₃N₂.

1)b. A polyatomic ion is an ion composed of more than one atom.Ammonium is a polyatomic ion that has a positive charge.

(1)c This is governed by the law of definite proportion. Carbon and oxygen combine in 3:8 ratio. So 11 g of carbon dioxide is formed.

Hence, in the latter case too, only 8 g of O2 will be reacted with 3g of carbon (because carbon is the limiting reagent here ) to form 11g of CO2 and 42 g of oxygen will remain unreacted.

Thus the answer becomes 11g of Carbon!!