Question

Calcium combines with oxygen to form calcium oxide. How many litres of oxygen (at STP) are required to make of CaO ?

Answer 1

Answer:

[{ First, you are might to be informed how much CaO is to be made at stp.}]. [ but if 1 gm of CaO is to be made then follow the following....}]

2Ca + O2 = 2CaO

molar mass of CaO is 56 gm

so 2x56 = 112 gm of CaO is formed from 22.4 lit( volume of 1 lit O2 at stp) of O2.

then volume of O2 to make 1 gm of CaO is [ (22.4/56) x 1 ] = 0.4 lit.( at stp).

......

[{ if 1 mole of CaO is to be made then the answer is following.... }]

and to make 1 mole of CaO , O2 needed [ (22.4/112) x 56 ] lit = 11.2 lit.

Explanation:

hope this will help you

Answer 2

The number of liters of oxygen (at STP) that is required to make CaO is 11.2 L of oxygen.

Given: Calcium combines with oxygen to form calcium oxide.

To Find:

The number of liters of oxygen (at STP) that is required to make CaO

Solution:

1. In this question, the amount of CaO formed is not given. So, we assume it to be 1 mole.

2. Calcium combines with oxygen to form calcium oxide according to,

    2 Ca + O2 → 2 CaO

      Molar mass of CaO = 56 gm

      So, according to stoichiometry, we get;

       2 moles of CaO is formed from = 1 mole of O2

   ⇒ 1 mole of CaO is formed from = ( 1/2 ) mole of O2

                                                            = ( 22.4 / 2 ) L of O2

                                                            = 11.2 L of oxygen

Hence, the number of liters of oxygen (at STP) that is required to make CaO is 11.2 L of oxygen.

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