1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ruslelena [56]
3 years ago
5

Combustion of 7.54 g of liquid benzene (C6H6) causes a temperature rise of 50.3°C in a constant-pressure calorimeter that has a

heat capacity of 6.27 kJ/°C. What is ∆H for the following reaction?C6H6(l) + O2(g) → 6CO2(g) + 3H2O(l)
Chemistry
1 answer:
Iteru [2.4K]3 years ago
4 0

Answer:

-3268 kJ/mol

Explanation:

The calorimeter is an equipment used to measure the heat from a combustion reaction. The heat can be calculated by:

Q = C*ΔT

Where Q is the heat, C is the heat capacity of the calorimeter, and ΔT is the variation of the temperature. So:

Q = 6.27 * 50.3

Q = 315.381 kJ

Because the calorimeter is adiabatic, the heat absorbed by it must be equal to the heat released for the reaction, so the heat of the reaction is:

Q = -315.381 kJ

The change in enthalpy (ΔH) is the heat divided by the number of moles of the limiting reactant. The combustion is commonly done with oxygen in excess, so benzene is the limiting reactant. Benze has a molar mass equal to 78.11 g/mol, so the number of moles is:

n = mass/molar mass

n = 7.54/78.11

n = 0.0965 moles

ΔH = Q/n

ΔH = -315.381/0.0965

ΔH = -3268 kJ/mol

You might be interested in
A plot of velocity versus substrate concentration for a simple enzyme-catalyzed reaction produces a _____. This indicates that a
kirza4 [7]

Answer:

B) hyperbolic curve; saturated with substrate

Explanation:

Enzymatic kinetics studies the speed of enzyme catalyzed reactions. These studies provide direct information about the mechanism of the catalytic reaction and the specificity of the enzyme. The speed of a reaction catalyzed by an enzyme can be measured with relative ease, since in many cases it is not necessary to purify or isolate the enzyme. The measurement is always carried out under the optimal conditions of pH, temperature, presence of cofactors, etc., and saturating substrate concentrations are used. Under these conditions, the reaction rate observed is the maximum speed (Vmax). The speed can be determined either by measuring the appearance of the products or the disappearance of the reagents.

Following the rate of appearance of product (or disappearance of the substrate) as a function of time, the so-called reaction progress curve is obtained, or simply, the reaction kinetics. This curve is represented by a hyperbolic curve

5 0
3 years ago
What is the volume of stank of nitrogen that contains 17 moles of nitrogen at 34 C under 12,000Pa?
Otrada [13]

Answer:

3626.76dm³

Explanation:

Given parameters:

Number of moles of Nitrogen in tank = 17moles

Temperature of the gas = 34°C

Pressure on the gas = 12000Pa

Unkown:

Volume of the tank, V =?

Converting the parameters to workable units:

We take the temperature from °C to Kelvin

K = 273 +  °C  = 273 + 34 = 307k

Taking the pressure in Pa to atm:

101325Pa = 1atm

12000Pa = 0.118atm

Solution:

To solve this problem, we employ the use of the ideal gas equation. The ideal gas law combines three gas laws which are the Boyle's law, Charles's law and the Avogadro's law.

            It is expressed as PV = nRT

The unknown is the Volume and we make it the subject of the formula

             V = \frac{nRT}{P}

Where R is called the gas constant and it is given as 0.082atmdm³mol⁻¹K⁻¹

Therefore  V = \frac{17 x 0.082 x 307 }{0.118} = 3626.76dm³

3 0
3 years ago
Read 2 more answers
How much<br>much hydrogen gas evolved<br>when 1.5 current is passed through water for 1.5 hours?​
evablogger [386]

0.042 moles of Hydrogen evolved

<h3>Further explanation</h3>

Given

I = 1.5 A

t = 1.5 hr = 5400 s

Required

Number of Hydrogen evolved

Solution

Electrolysis of water ⇒ decomposition reaction of water into Oxygen and Hydrogen gas.

Cathode(reduction-negative pole) : 2H₂O(l)+2e⁻ ⇒ H₂(g)+2OH⁻(aq)

Anode(oxidation-positive pole) : 2H₂O(l)⇒O₂(g)+4H⁻(aq)+4e⁻

Total reaction : 2H₂O(l)⇒2H₂(g)+O₂(g)

So at the cathode H₂ gas is produced

Faraday : 1 mole of electrons (e⁻) contains a charge of 96,500 C

\tt mol~e^-=\dfrac{Q}{96500}

Q = i.t

Q = 1.5 x 5400

Q = 8100 C

mol e⁻ = 8100 : 96500 = 0.084

From equation at cathode , mol ratio e⁻ : H₂ = 2 : 1, so mol H₂ = 0.042

4 0
3 years ago
Classify the following substances as acids or bases.
ella [17]
A=acid
B=it say neither it say it’s alkaline
C=acid
D= it say neither it say it’s alkaline
8 0
2 years ago
Read 2 more answers
A scholar measures 20 mL of room temperature water (22ºC) and adds 80 mL of 75°C water to it, following the
Leni [432]

Answer:

Data is not valid

Explanation:

When two liquids having different temperatures are mixed, regardless of the volumes, the final mix temperature will ALWAYS be between the initial temperature values.

1st Law Thermo => Law of Conservation of Energy => Energy can not be created nor destroyed, only changed in form. Mixing 22°C with 75°C will NOT result in a mix having a final temperature of 80°C.

∑ΔE = 0 => (mcΔT)₁ + (mcΔT)₂ = 0

[(20g)(1cal/g·°C)(Tₓ - 22°C)] + [(80g)(1cal/g·°C)(Tₓ - 75°C)] = 0

=> 20(Tₓ - 22) + 80(Tₓ - 75) = 0

=> 20Tₓ - 440 + 80Tₓ - 75 = 0

=> 100Tₓ = 440 + 75 = 515

=> Tₓ = (515/100)°C = 51.5°C final mix temperature

4 0
3 years ago
Other questions:
  • Why is it important to learn about fuels and gases?
    14·1 answer
  • In a system when energy is transformed from one form to another
    5·1 answer
  • How much heat is evolved in converting 1.00 mol of steam at 140.0 ?C to ice at -45.0 ?C? The heat capacity of steam is 2.01 J/(g
    11·1 answer
  • Which type of solid has the lowest and highest melting point?
    12·1 answer
  • What are the characteristics of a gas? no definite shape but a definite volume a definite volume and definite shape a definite s
    6·2 answers
  • Write a balanced chemical equation based on the following description:
    9·1 answer
  • Which of the variables listed (arm length and amplitude) above do you predict will affect the pendulum’s period? How do you thin
    15·1 answer
  • List 2 metals that can be used as fuel
    10·1 answer
  • Under what conditions would pressure affect the reaction rate?
    8·2 answers
  • choose the true statement(s) about ions. to be marked correct, you’ll need to select all true statements, as there may be more t
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!