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3 years ago

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The flame produced by the burner of a gas (propane) grill is a pale blue color when enough air mixes with the propane (C3H8) to

burn it completely. For every gram of propane that flows through the burner, what volume of air is needed to burn it completely? Assume that the temperature of the burner is 195.0 Celcius, the pressure is 1.1 atmosphere, and the mole fraction of O2 in air is 0.21.

1 answer:

adelina 88 [10]3 years ago

6 0

Answer:

At the burner temp. and pressure, 18.85 litres of air is needed to completely combust each gram of propane

Explanation:

The combustion stoichiometry is as follows:

C₃H₈ + 5O₂ = 4 H₂O + 3CO₂ The molecular weights (g/mol) are:

MW 44 5x32 4x18 3x44

So each gram of propane is 1/44 = 0.02272 mol propane

and will need 5 x 0.02272 = 0.1136 mol oxygen

At 0.21 mol fraction oxygen in air, 0.1136 / 0.21 = 0.54 mol air is needed to burn the propane.

At the low pressure in the burner we can use the Ideal Gas Law

PV=nRT, or V = nRT/P

P = 1.1 x 101325 Pa = 111457 Pa

T = 195°C + 273 = 468 K

R = 8.314

and we calculated n = number of moles air = 0.54 mol

So V m³ = 0.54 x 8.314 x 468 / 111457 = 0.0188 m³ = 18.85 litres air.

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The titration of 25.0 mL of an iron(II) solution required 18.0 mL of a 0.145 M solution of dichromate to reach the equivalence p

Svetlanka [38]

Answer:

0.64 M

Explanation:

Given:

Volume of iron(II) solution (V₁) = 25.0 mL = 0.025 L

Molarity of iron(II) solution (M₁) = ?

Number of moles of iron(II) solution (n₁) = ?

Volume of dichromate solution (V₂) = 18.0 mL = 0.018 L

Molarity of dichromate solution (M₂) = 0.145 M

Number of moles of dichromate solution (n₂) = ?

Molarity is equal to the ratio of moles and volume.

So, molarity of dichromate solution is given as:

$M_2=\frac{n_2}{V_2}\\\\n_2=M_2\times V_2=0.145\times 0.018 = 2.61\times 10^{-3}\ mol$

Now, let us write the complete balanced reaction for the given situation.

So, the complete balanced equation is given below.

$6Fe^{2+}(aq)+Cr_2O_7^{2-}(aq)+14H^+(aq)\to 6Fe^{3+}(aq)+2Cr^{3+}(aq)+7H_2O$

From the equation, it is clear that, 1 mole of dichromate is required for 6 moles of iron(II) solution.

So, using unitary method, we find the number of moles of iron(II) solution.

1 mole of dichromate = 6 moles of iron(II)

∴ n₂ moles of dichromate = 6n₂ moles of iron(II)

= $6\times 2.61\times 10^{-3}=0.016\ mol\ Fe^{2+}$

So, 0.016 moles of iron(II) is needed. Therefore, $n_1=0.016\ mol$

Now, molarity of iron(II) solution is given as:

Molarity = Moles ÷ Volume

$M_1=\frac{n_1}{V_1}\\\\M_1=\frac{0.016\ mol}{0.025\ L}=0.64\ M$

Therefore, the molarity of the iron(II) solution is 0.64 M.

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2 years ago

Which of the following would be classified as an acid to the Arrhenius definition

mixer [17]

Any substance that increases the concentration of $H^+$ in aqueous solutions is Arrhenius's acid.

<h3>What are Arrhenius acids?</h3>

Arrhenius define acids as substances with the chemical capacities to increase the concentration of hydrogen ion in aqueous solutions.

Thus, substances like HCl, HNO3, HBr, etc. would be considered an acid. This is because they ionize in aqueous solutions as follows:

HCl ---> $H^+$ + $Cl^-$

$HNO_3 --- > H^+ + NO_3^-$

$HBr --- > H^+ + Br^-$

More on Arrhenius acids can be found here: brainly.com/question/9936252

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1 year ago

Read 2 more answers

Commercial grade HCl solutions are typically 39.0% (by mass) HCl in water. Determine the molality of the HCl, if the solution ha

marta [7]

Molality of the solution is defined as the number of moles of a substance dissolved divided by the mass of the solvent:

Molality = number of moles / solvent mass

From the concentration of 39% (by mass) of HCl in water, we construct the following reasoning:

in 100 g solution we have 39 g hydrochloric acid (HCl)

number of moles = mass / molecular weight

number of moles of HCl = 39 / 36.5 = 1.07 moles

solvent (water) mass = solution mass - hydrochloric acid mass

solvent (water) mass = 100 - 39 = 61 g

Now we can determine the molality:

molality = 1.07 moles / 61 g = 0.018

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2 years ago

COCl2(g) decomposes according to the equation above. When pure COCl2(g) is injected into a rigid, previously evacuated flask at

mestny [16]

<u>Answer:</u> The value of $K_p$ for the reaction at 690 K is 0.05

<u>Explanation:</u>

We are given:

Initial pressure of $COCl_2$ = 1.0 atm

Total pressure at equilibrium = 1.2 atm

The chemical equation for the decomposition of phosgene follows:

$COCl_2(g)\rightleftharpoons CO(g)+Cl_2(g)$

Initial: 1 - -

At eqllm: 1-x x x

We are given:

Total pressure at equilibrium = [(1 - x) + x+ x]

So, the equation becomes:

$[(1 - x) + x+ x]=1.2\\\\x=0.2atm$

The expression for $K_p$ for above equation follows:

$K_p=\frac{p_{CO}\times p_{Cl_2}}{p_{COCl_2}}$

$p_{CO}=0.2atm\\p_{Cl_2}=0.2atm\\p_{COCl_2}=(1-0.2)=0.8atm$

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Hence, the value of $K_p$ for the reaction at 690 K is 0.05

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2 years ago

What’s the difference between heterogeneous and homogeneous mixtures?

Ronch [10]

Answer:

Mixtures can be either homogeneous or heterogeneous. A mixture in which its constituents are distributed uniformly is called homogeneous mixture, such as salt in water. A mixture in which its constituents are not distributed uniformly is called heterogeneous mixture, such as sand in water.

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