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taurus [48]
3 years ago
13

Find the percentage of mass in each of the element Ca ( HCO3)2 (Ca= 40, H = 1, O = 16, C= 35)​

Chemistry
1 answer:
Alex787 [66]3 years ago
3 0

Answer:

% Ca = 24.69%

% H = 1.2%

% C = 14.8%

% O = 59.25%

Explanation:

The percentage by mass of each element can be calculated by dividing the mass of each element in the compound by the molar mass of the compound.

Molar mass of Ca(HCO3)2

Where; (Ca= 40, H = 1, O = 16, C= 12)

= 40 + {1 + 12 + 16(3)}2

= 40 + {13 + 48}2

= 40 + {61}2

= 40 + 122

= 162g/mol

- % mass of Ca = 40/162 × 100

= 0.2469 × 100

= 24.69%

- % mass of H = 2/162 × 100

= 0.012 × 100

= 1.2%

- % mass of C = 24/162 × 100

= 0.148 × 100

= 14.8%

- % mass of O = 96/162 × 100

= 0.5925 × 100

= 59.25%

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A gas contains 75.0 wt% methane, 10.0% ethane, 5.0% ethylene, and the balance water. (a) Calculate the molar composition of this
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a)  molar composition of this gas on both a wet and a dry basis are

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Let assume we have 100 g of mixture of gas:

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Mass of methane =75 g

Mass of ethane = 10 g

Mass of ethylene = 5 g

∴ Mass of the balanced water: 100 g - (75 g + 10 g + 5 g)

Their molar composition can be calculated as follows:

Molar mass of methane CH_4}= 16 g/mol

Molar mass of ethane C_2H_6= 30 g/mol

Molar mass of ethylene C_2H_4 = 28 g/mol

Molar mass of water H_2O=18g/mol

number of moles = \frac{mass}{molar mass}

Their molar composition can be calculated as follows:

n_{CH_4}= \frac{75}{16}

n_{CH_4}= 4.69 moles

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n_{C_2H_6} = 0.33 moles

n_{C_2H_4} = \frac{5}{28}

n_{C_2H_4} = 0.18 moles

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n_{H_2O}= 0.56 moles

Total moles of gases for wet basis = (4.69 + 0.33 + 0.18 + 0.56) moles

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Total moles of gas for dry basis = (5.76 - 0.56)moles

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Ratio of moles of water to the moles of dry gas = \frac{n_{H_2O}}{n_{drygas}}

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    CH_4 + 2O_2_{(g)} ------> CO_2_{(g)} +2H_2O

4.69         2× 4.69

moles       moles

   C_2H_6+ \frac{7}{2}O_2_{(g)} ------> 2CO_2_{(g)} + 3H_2O

0.33      3.5 × 0.33

moles    moles

    C_2H_4+3O_2_{(g)} ----->2CO_2+2H_2O

0.18           3× 0.18

moles        moles

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CH_4 = 4.69 k moles/h\\C_2H_6 = 0.33 k moles/h\\C_2H_4=0.18kmoles/h

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Thus, moles of air required = \frac{1}{0.21}*11.075

= 52.7 k mole

30% excess air = 0.3 × 52.7 k moles

= 15.81 k moles

Total air required = (52.7 + 15.81 ) k moles/h

= 68.51 k moles/h

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