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Viefleur [7K]
3 years ago
8

Sometimes in lab we collect the gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolat

e and measure the amount of gas produced. Wala Suppose the H, gas evolved by a certain chemical reaction taking place at 40.0 °C is collected over water, using an apparatus something like that in the sketch, and the final volume of gas in the collection tube is measured to be 80.0 mL. Sketch of a gas-collection apparatus.
Calculate the mass of H, that is in the collection tube. Round your answer to 2 significant digits. You can make any normal and reasonable assumption about the reaction conditions and the nature of the gases. XS ?
Chemistry
1 answer:
ad-work [718]3 years ago
7 0

Answer:

The correct answer is 0.00582 grams.

Explanation:

In order to solve the question, let us consider the vapor pressure of H2O, as hydrogen gas is collected over water, therefore, we have to consider the vapor pressure of water in the given case. Let us assume that the pressure is 760 torr or 1 atm.

It is known that the vapor pressure of water at 40 degree C is 53.365 torr (Based on the data).

Therefore, the pressure of H2 will be,

P = 760-55.365 = 704.635 torr or 704.635/760 = 0.9272 atm

The volume of the hydrogen gas collected in the tube is 80 ml or 0.08 L

Temperature in Kelvin will be 40+273 = 313 K

To calculate the moles of hydrogen (H2) gas, there is a need to use the ideal gas equation, that is, PV= nRT, in this R is the gas constant, whose value is 0.0821 L atm/molK, and n is the moles of the gas.

By inserting the values in the equation we get:

PV = nRT

n = PV/RT = 0.9272 *0.08 / 0.0821 * 313

n = 0.00289 moles

The mass of H2 will be moles * molar mass = 0.00289 * 2.016

= 0.00582 grams.

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Determine the balanced chemical equation for this reaction. C8H18(g)+O2(g)→CO2(g)+H2O(g)
ankoles [38]

Answer: balanced reaction equation

C8H18(g) + 25/2 O2(g) ---------> 8CO2(g) + 9H2O(l)

Explanation:

Part A- coefficients

1, 25/2,8,9

Part B

Oxygen is the limiting reactant

Part C

If 1 mole of octane produced 9 moles of water from the balanced reaction equation

0.28 moles of octane will produce 0.28×9= 2.52 moles of water

Part D

If 12.5 moles of oxygen reacts with 1 mole of octane

0.63 moles of oxygen will react with 0.63/12.5=0.0504moles of octane

Amount of octane left= 0.280-0.0504=0.2296 moles

4 0
3 years ago
Given the following reaction: 3D(g) + E(g) + 2F(g) → 5G(g) + 4H(g)
evablogger [386]

Answer:

Explanation:

Hello,

The law of mass action, allows us to know the required amounts, thus, for this chemical reaction it is:

\frac{1}{-3} \frac{d[D]}{dt} =\frac{1}{-1} \frac{d[E]}{dt} =\frac{1}{-2} \frac{d[F]}{dt} =\frac{1}{5} \frac{d[G]}{dt} =\frac{1}{4} \frac{d[H]}{dt}

Now, we answer:

(a)

\frac{d[H]}{dt}=4*\frac{1}{-3} *(-0.12M/s)=0.16M/s

(b)

\frac{d[E]}{dt}=-1*\frac{1}{5} *(0.2M/s)=-0.04M/s

(c) Since no initial data is specified, we could establish the rate of the reaction as based of the law of mass action:

r=\frac{1}{-3} \frac{d[D]}{dt} =\frac{1}{-1} \frac{d[E]}{dt} =\frac{1}{-2} \frac{d[F]}{dt} =\frac{1}{5} \frac{d[G]}{dt} =\frac{1}{4} \frac{d[H]}{dt}

Thus, any of the available expressions are suitable to quantify the rate of the reaction.

Best regards.

4 0
3 years ago
During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules. Which of the following, i
babunello [35]

Answer:

(A.) CO2, H2O

Explanation:

The chemical equation for respiration process is:

C_{6}H_{12} O_{6} + 6O_{2} → 6CO_{2} + 6H_{2} O + ATP↑

Energy is released during the biochemical process in the organism's cells in form of ATP. Byproducts of the reaction are carbon dioxide and water molecules.

Let me know if you require any further assistance.

4 0
2 years ago
Which represents the self ionization of water at 25 degrees
gayaneshka [121]
This question comes with four answer choices:

<span>A. H2O + H2O ⇄ 2H2 + O2

B. H2O + H2O⇄  H2O2 + H2

C. H2O + H2O ⇄ 4H+ + 2O2-

D. H2O + H2O ⇄  H3O+ + OH-

Answer: option </span><span>D. H2O + H2O ⇄  H3O+ + OH-

(the +sign next to H3O is a superscript, as well as the - sing next to OH)

Explanation:

The self-ionization of water, or autodissociation, produces the two ions H3O(+) and OH(-). The presence of ions is what explain the electrical conductivity of pure water.

</span><span>In this, one molecule of H2O loses a proton (H+) (deprotonates) to become a hydroxide ion, OH−. Then, he <span>hydrogen ion, H+</span>, immediately protonates another water molecule to form hydronium, H3O+.
</span>
7 0
3 years ago
Which equation shows how to calculate how many grams (g) of KOH would be needed to fully react with 4 mol Mg(OH)2? The balanced
bazaltina [42]
Mole ratio:

MgCl₂ + 2 KOH = Mg(OH)₂ + 2 KCl

2 moles KOH ---------------- 1 mole Mg(OH)₂
moles KOH ------------------- 4 moles Mg(OH₂)

moles KOH = 4 x 2 / 1

= 8 moles of  KOH

molar mass KOH = 56 g/mol

mass of KOH = n x mm

mass of  KOH = 8 x 56

= 448 g of KOH 

hope this helps!

3 0
3 years ago
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