Question

CaCo3 decomposes to give Co2 gas according to the equation CaCo3(s) gives CaO(s)+Co2(g).calculate the mass of CaO(s)produced on complete decomposition of 5.0g of CaCo3.given molar masses of CaO=56g,Co2=44g.

Answer 1

The decomposition of CaCO3 is as follows:
    
 
        CaCO3(s) ---------> CaO(s) + CO2(g) 

     The mole ratio of the equation is 1:1:1....this 1 mole of CaCO3 yields 1 mole of CaO and 1 mole of CO2.

Calculate the moles of CaCO3:
moles = mass/molar mass
 moles = 5/100
    = 0.05 moles
This means that the moles of the CaO produced is also 0.05 moles since the mole ratio is 1:1:1

mass = moles × molar mass
         =  0.05 × 56
  2.8 grams 

Mass of CO2:
 mass = moles × molar mass

                  0.05 × 44
                  = 2.2 grams of CO2

Answer 2

AnswerCaCO3 decomposition:

CaCO3 -> CaO + CO2

The first thing to do here is to calculate the relative formula mass of CaCO3 and CO2.

RFM of CaCO3 = 40 g + 12 g + (16 g x 3) = 100 g

RFM of CO2 = 12 g + (16 g x 2) = 44 g

The decomposition equation shows 1 CaCO3 goes to 1 CaO and 1 CO2.

We have 50 g of CaCO3, effectively we have half a CaCO3.

50 g / 100 g = 0.5

In order to get the mass of CO2 we need to times the RFM of CO2 by 0.5 (or divide by 2) because of the ratio of CaCO3 to CO2:

44 g x 0.5 = 22 g

22 g of CO2 are obtained from decomposition of 50 g of CaCO3.:

Explanation: