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Name Date Consider the following Reaction. A chemist allows 23.2g of CH4 and 78.

ID: 559779 • Letter: N

Question

Name Date Consider the following Reaction. A chemist allows 23.2g of CH4 and 78.3g O2 to react. When the reaction is finished, the chemist collects 52.7g CO2. Determine the limiting reagent, theoretical yield, and percent yield for the reaction. [Hint: first step balance the Chemical Reaction] Consider the following Reaction. A chemist allows 30.6g of Mg(OH)2 and 63.6g H3PO4 to react. When the reaction is finished, the chemist collects 34.7g Mgs(PO)2 Determine the limiting reagent, theoretical yield, and percent yield for the reaction. [Hint: first step balance the Chemical Reaction]

Explanation / Answer

1)

a)

Molar mass of CH4 = 1*MM(C) + 4*MM(H)

= 1*12.01 + 4*1.008

= 16.042 g/mol

mass of CH4 = 23.2 g

we have below equation to be used:

number of mol of CH4,

n = mass of CH4/molar mass of CH4

=(23.2 g)/(16.042 g/mol)

= 1.446 mol

Molar mass of O2 = 32 g/mol

mass of O2 = 78.3 g

we have below equation to be used:

number of mol of O2,

n = mass of O2/molar mass of O2

=(78.3 g)/(32 g/mol)

= 2.447 mol

we have the Balanced chemical equation as:

CH4 + 2 O2 ---> CO2 + 2 H2O

1 mol of CH4 reacts with 2 mol of O2

for 1.4462 mol of CH4, 2.8924 mol of O2 is required

But we have 2.4469 mol of O2

so, O2 is limiting reagent

b)

we will use O2 in further calculation

Molar mass of CO2 = 1*MM(C) + 2*MM(O)

= 1*12.01 + 2*16.0

= 44.01 g/mol

From balanced chemical reaction, we see that

when 2 mol of O2 reacts, 1 mol of CO2 is formed

mol of CO2 formed = (1/2)* moles of O2

= (1/2)*2.4469

= 1.223 mol

we have below equation to be used:

mass of CO2 = number of mol * molar mass

= 1.223*44.01

= 53.84 g

Answer: theoretical yield = 53.8 g

% yield = actual mass*100/theoretical mass

= 52.7*100/53.84

= 97.9 %

Answer: 97.9 %

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