What amount of the excess reagent remains after the reaction is complete? grams

Question

What amount of the excess reagent remains after the reaction is complete?  grams

What mass of the excess reagent remains after the reaction is complete?   grams

What amount of the excess reagent remains after the reaction is complete?  grams

4)

For the following reaction,  6.35 grams of  carbon monoxide are mixed with excess  oxygen gas . The reaction yields  8.12 grams of carbon dioxide .

What is the percent yield for this reaction ?

5) For the following reaction,  3.43 grams of  iron are mixed with excess  oxygen gas . The reaction yields  3.02 grams of  iron(II) oxide .

Pls do all or as much as possible, tysm in advance

%

Explanation / Answer

1. Al2O3 + 3H2SO4 --> Al2(SO4)3 + 3H2O

Molecular weight of Al2O3=> 2*molar mass of aluminum+3*molar mass of Oxygen=> 2*27+3*16=> 54+48 => 102 g/mol

so, moles of aluminum oxide=> 35.9 g/ 102 g/mol=> 0.35 moles

Molecular weight of H2SO4=> 2* molar mass of hydrogen + 4 * Molar mass of Oxygen+1*molar mass of sulphur=> 2*1+4*16+1*32=> 2+64+32=> 98 g/mol

number of moles of sulphuric acid=> 93.9 g/ 98 g/mol=> 0.96 mol

as 3 moles of H2SO4 reacts with 1 mole of Al2O3 to form Al2(SO4)3 , 0.35 moles of Al2O3 will require 1.05 moles, hence H2SO4 is the limiting reagent.

Aluminium sulfate molecular weight=> 2*molar mass of aluminum+ 3* molar mass of sulphur + 12* molar mass of Oxygen=> 2*27+3*32+12*16=> 54+96+192=> 342 g/mol

so, aluminum sulfate formed=> 0.35 moles* 342 g/mol=> 119.7 grams

2. 2Co+ O2 ---> 2Co2

Molecular weight of carbon monoxide=> molar mass of carbon+ molar mass of Oxygen

=> 12+16=> 28 g/mol

Molecular weight of carbon dioxide=> molar mass of carbon+ 2*molar mass of Oxygen=> 12+2*16=> 12+32= 44 g/mol

Oxygen=> 32 g/mol

so, number of moles of oxygen=> 6.14 g/ 32 g/mol=> 0.19 mol

number of moles of carbon monoxide=> 14.3 grams / 28 g/mol=> 0.51 moles

so, Oxygen is the limiting reagent even when 2 moles of Co react with 1 mole of O2.

Maximum carbon dioxide formed=> 2*0.19 moles=> 0.38 moles

=> 0.38 moles * 44 g/mol=> 16.72 grams of Co2 formed.

3. S + 2Co --> SO2 + 2C

molecular weights given in previous parts.

number of moles of carbon monoxide=> 20.6 g/ 28 g/mol=> 0.74 moles

number of moles of S => 9.97 g/32 g/mol=> 0.31 moles

From reaction, one mole of S reacts with 2 moles of carbon monoxide.

In this case sulphur is the limiting reagent.

SO2 formed=> 0.31 moles => 0.31 moles* 64 g/mol=> 19.84 grams

4. 2Co + O2 --> 2CO2

Number of moles of CO=> 6.35 g/ 28 g/moles=> 0.23 moles

number of moles of CO2 produced=> 8.12 g/ 44 g/mol=> 0.18 moles

so, theoretical yield of carbon dioxide=> 0.18/0.23=> 78.26%

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