Question

How many miles of carbon dioxide gas can be produced if 25 g of cr2(co3)3 are reacted with excess nitric acid hno3 ?

Answer 1

Answer:

0.264 moles of carbon dioxide are produced.

Explanation:

Limiting reagent : The reactant that is consumed in a reaction is called the limiting reagent.

Molar mass = mass of substance  in grams present in 1 mole of the compound.

before solving this question,

It is needed to know , the molar mass of  cr2(co3)3 and CO2

Molar mass of  cr2(co3)3  = 2(mass of Cr) + 3(massof C) + 9(mass of O)

                                           = 2(52) + 3(12) + 9(16)

                                          = 104 + 36 + 144

                                          = 284 g

This means 1 mole of  cr2(co3)3  = 284 g............(1)

Molar mass of CO2 = mass of C + 2(mass of O)

                                  = 12 + 2(16)

                                  = 12 + 32

                                  = 44 g

This means 1 mole of CO2 contain 44 g of it.

So, 3 mole of CO2 contain = 44x3 g

3 mole of CO2 contain = 132 g.............(2)

The balance equation for the reaction is :

$Cr_{2}(CO_{3})_{3}+6HNO_{3}\rightarrow$

$2Cr(NO_{3})_{3} +8H_{2}O+3CO_{2}$

HNO3 = excess reagent , it can't be used in for predicting the moles of CO2

$Cr_{2}(CO_{3})_{3}$= Limiting reagent = It will tell the amount of CO2 that will be produced

In the balanced equation ,

1 mole of cr2(co3)3  is giving = 3 mole of CO2

Use equation (1) and (2)

284 g of cr2(co3)3  is giving = 132 g of CO2

1 gram of cr2(co3)3  is giving =

$\frac{132}{284}$ g of CO2

25 g of cr2(co3)3 will give =

$\frac{132}{284}\times 25$ g of CO2

= 11.62 gram CO2

now , moles of CO2 can be calculated using ,

$moles=\frac{given\ mass}{Molar\ mass\ of\ CO2}$

$moles =\frac{11.6}{44}$      (molar mass of co2 = 44 g)

moles of CO2 = 0.264