Chemistry, 08.10.2019 03:10 robert7248

Amixture of methane and air is capable of being ignited only if the mole percent of methane is between 5% and 15%. a mixture containing 9.00 mole% methane in air flowing at a rate of 700.0 kg/h is to be diluted with pure air to reduce the methane concentration to the lower flammability limit. calculate the required flow rate of air in mol/h and the percent by mass of oxygen in the product gas. (note: air may be taken to consist of 21.0 mole% o2 and 79.0 mole% n2 and hence to have an average molecular weight of 29.0).

Answers: 3

Show answers

Answers

Answer from: ty1090

The required flow rate of air in mol/h is 20144 and the percent by mass of oxygen in the product gas is 23,1%.

Explanation:

The air of 9 mole% methane have an average molecular weight of:

0,09*16,04g/mol + 0,91*29g/mol = 27,8g/mol

And a flow of 700'000g/h÷27,8g/mol = 25180 mol/h

In the reactor where methane solution and air are mixed:

In = Out

Air balance:

91% air×25180 mol/h + 100% air×X = 95%air×(X+25180)

Where X is the flow rate of air in mol/h.

Solving, X = 20144 mol air/h

The air in the product gas is:

95%×(20144 + 25180) mol/h = 43058 mol air× 21%O₂ = 9042 mol O₂ ×32g/mol = 289 kg O₂

43058 mol air×29g/mol 1249 kg air

Percent mass of oxygen in the product gas is: =0,231 kg O₂/ kg air* 100 = 23,1%

I hope it helps!

Answer from: Quest

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

Answer from: Quest

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = $25^oc$ = 298 k $)0^oc=273kelvins$

$o_3+3no\rightarrow 3no_2,\delta h_{reaction}=? [/)</p><p>[tex]\delta h_{no}=90.4kj/mol$

$\delta h_{no_2}=33.85kj/mol$

$\delta h_{o_3}=142.2kj/mol$

$\delta h_{reaction}=\sum \delta h_{products}-\sum\delta h_{reactants}=3\times\delta h_{no_2}-(3\times \delta h_{no}+\delta h_{o_3})$

$\delta h_{reaction}=33.85-(90.4+142.2)=-311.85kj/mol$

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

$v_{no}=12.00 l,v_{o_3}=8.50 l$

$pv_{no}=n_{no}rt=1atm \times 12.00 l=n_{no}\times 0.0821 atml/k mol \times 298 k$

$n_{no}=0.49 moles$

$pv_{o_3}=n_{o_3}rt=1atm \times 8.50 l=n_{o_3}\times 0.0821 atml/k mol \times 298 k$

$n_{o_3}=0.34 moles$

according to reaction 3 moles no are reacting with 1 mol of $o_3$ ,then 0.49 mol of no will react with $\frac{1}{3}\times 0.49$ moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and $o_3$ is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :

$\delta h_{reaction}\times \text{moles of no}=-311.85kj/mol\times 0.49 mol=-152.80kj/mol$

Another question on Chemistry

Chemistry, 22.06.2019 12:20

Adeuteron, 21h, is the nucleus of a hydrogen isotope and consists of one proton and one neutron. the plasma of deuterons in a nuclear fusion reactor must be heated to about 3.02×108 k . what is the rms speed of the deuterons? express your answer using two significant figures.

Answers: 1

Answer

Chemistry, 22.06.2019 14:00

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.

Answers: 3

Answer

Chemistry, 22.06.2019 21:50

What is a main difference between a mixture and a pure substance? a mixture is only a liquid, but a pure substance can be in any state.a mixture looks the same throughout, but a pure substance does not.1 a mixture can vary in composition, but a pure substance has a set composlo a mixture can be made up of a single compound, but a pure substance car

Answers: 2

Answer

Chemistry, 23.06.2019 05:40

Which order shows the levels of organization from largest to smallest? organism, organ system, cell, organ, tissue organism, tissue, organ system, organ, cell organism, organ, organ system, cell, tissue organism, organ system, organ, tissue, cell

Answers: 2

Answer

You know the right answer?

Amixture of methane and air is capable of being ignited only if the mole percent of methane is betwe...

Questions