Question

how many moles of iron(III) chloride can be produced when 2.3 moles of iron atom react in the presence of 3.3 moles of chlorine gas? 2 fe(s)+3Cl2(g)-->2FeCl3(s)

1) 2 mole

2) 2.3 mole

3) 3.3 mole

4) 2.2 mole

5) 5.6 mole

2 Potassium reacts with elemental bromine in a combination reaction to form an ionic compound. how many moles of bromine are needed to react with 1.5 moles of potassium?(hint write and balance chemical equation

1)3 mol

2)1 mole

3)0.75 mol

4)4.5 mol

5)1.5 mol

3 write and balance the equation for combustion of C15H28O3. write the sum of coefficients

1)52

2)102

3)51

4)71

5)101

Answer 1

1.

2Fe +3Cl2 - - - >2FeCl3

given moles of Fe =2.3

moles of Cl2 =3.3

first we will see which is limiting reagent.

as we can see in reaction

2 moles of Fe reacts with =3 moles of Cl2

then 2.3moles of Fe will react with =(3/2)*2.3 =6.9/2 =3.45

but we are given only 3.3 moles of Cl2. Thus Cl2 is limiting reagent.

so as in reaction we have

3 moles of Cl2 react with Fe to give =2 moles of FeCl3

then 3.3 moles of Cl2 will give =(2/3)*3.3 =2.2 moles of FeCl3

thus option (4)is correct.

based on calculation, other options are incorrect.

2.

K. +Br. - - - > K⁺Br^-

as in reaction,

1 mole of Br reacts with =1 mole of potassium

so 1.5 moles of potassiumreacts with =1.5 moles of Br

so option (5)is correct.

based on calculation, other options are incorrect.

3.combustion reaction

2 C15H28O3 +41 O2 - - - - > 30 CO2 +28 H2O

now sum of coefficients =2 +41+30+28 =101

hence option(5) is correct.

based on calculation, other options are incorrect.

comment if any issue.

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