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
-BARSIC- [3]
3 years ago
12

The change in enthalpy is the change in heat energy of a reaction and is calculated by (Hint: Hess' Law): Group of answer choice

s
a. Sum of reactant enthalpies plus the sum of product enthalpies
b. Sum of reactant enthalpies minus the sum of product enthalpies
c. Sum of product enthalpies times the sum of reactant enthalpies
d. Sum of product enthalpies minus the sum of reactant enthalpies
Chemistry
1 answer:
Stolb23 [73]3 years ago
8 0

Answer:

d. Sum of product enthalpies minus the sum of reactant enthalpies

Explanation:

The standard enthalpy change of a reaction (ΔH°rxn) can be calculated using the following expression:

ΔH°rxn = ∑n(products) × ΔH°f(products) - ∑n(reactants) × ΔH°f(reactants)

where,

ni are the moles of products and reactants

ΔH°f(i) are the standard enthalpies of formation of products and reactants

You might be interested in
En un vaso de precipitado de un litro se coloca exactamente 500 mL de agua destilada a temperatura ambiente y se realizan dos ex
Serga [27]

Answer:

1) La masa del agua a temperatura ambiente es de 500 gramos, 2) La masa del agua cuando se congela es de 500 gramos, 3) La masa de agua que queda después de la evaporación es de 400 gramos, 4) Se ha evaporado 100 gramos de agua.

Explanation:

1) <em>¿Cuál es la masa de agua a temperatura ambiente?</em>

Podemos determinar la masa inicial del agua (m_{o}), medido en gramos, al conocer su densidad (\rho_{w}), medida en gramos por mililitro, y volumen inicial ocupado en el vaso de precipitado (V_{o}), medido en mililitros, a partir de la siguiente expresión:

m_{o} =\rho_{w}\cdot V_{o}

Si sabemos que \rho_{w} = 1\,\frac{g}{mL} y V_{o} = 500\,mL, entonces:

m_{o} = \left(1\,\frac{g}{mL} \right)\cdot (500\,mL)

m_{o} = 500\,g

La masa del agua a temperatura ambiente es de 500 gramos.

2) <em>¿Cuál es la masa de agua cuando se congela?</em>

Puesto que el proceso de congelación no implica transferencia de masa, la masa de agua se conserva al transformarse en hielo. Por tanto, la masa resultante es de 500 gramos.

3) <em>¿Cuál es la masa de agua que queda después de la evaporación?</em>

Durante la evaporación una parte del agua es transferida al aire, entonces podemos calcular la masa final (m_{f}), medido en gramos, de la sustancia al multiplicar el volumen final (V_{f}), medido en mililitros, por la densidad del agua (\rho_{w}), medida en gramos por mililitro,. Es decir,

m_{f} =\rho_{w}\cdot V_{f}

Si sabemos que \rho_{w} = 1\,\frac{g}{mL} y V_{f} = 400\,mL, entonces:

m_{f} = \left(1\,\frac{g}{mL} \right)\cdot (400\,mL)

m_{f} = 400\,g

La masa de agua que queda después de la evaporación es de 400 gramos.

4) <em>¿Qué masa de agua se evaporó? </em>

Determinamos que la masa evaporada de agua (m_{v}), medida en gramos, es igual a la diferencia entre las masas inicial y final, ambas medidas en gramos:

m_{v} =m_{o}-m_{f}

Si m_{o} = 500\,g y m_{f} = 400\,g, entonces tenemos que:

m_{v} = 500\,g -400\,g

m_{v} = 100\,g

Se ha evaporado 100 gramos de agua.

5 0
3 years ago
Construct a three-step synthesis of 1,2-epoxycyclopentane from cyclopentanol by dragging the appropriate formulas into the bins.
vladimir2022 [97]

Answer:

(1) Bromination, (2) E2 elimination and (3) epoxidation

Explanation:

  • In the first step, -OH group in cyclopentanol is replaced by more facile leaving group Br by treating cyclopentanol with PBr_{3}
  • In the second step, E2 elimination in presence of strong base e.g. NaOEt/EtOH produce cyclopentene
  • In the third step, treatment of cyclopentene with mCPBA produces 1,2-epoxycyclopentane
  • Full reaction scheme has been shown below

8 0
3 years ago
Pure carbon dioxide (PCO2 = 1 atm) decomposes at high temperature. For the reaction system 2 〖CO〗_2 (g) ⇌2 CO(g)+ O_2 (g) Is thi
julia-pushkina [17]

Answer:

The reaction decomposes more as T increases, therefore it is ENDOTHERMIC, meaning it requires energy to form CO and O₂.

Kp for each specie...

Kp = CO^2 O2 / (CO2)^2

for

T = 1500

Assume 1 atm for CO2, after % dissociation

P-CO2 left = 1*(1-0.048/100)= 0.99952

P-CO formed = 1-0.99952 = 0.00048

P-O2 = (1-0.99952)/2 = 0.00024

so..

Kp = CO^2 O2 / (CO2)^2

Kp = (0.00048^2)(0.00024) / (0.99952^2) = 5.53*10^-11

T = 2500

Assume 1 atm for CO2, after % dissociation

P-CO2 left = 1*(1-17.6/100)= 0.824

P-CO formed = 1-0.824= 0.176

P-O2 = (1-0.176)/2 = 0.088

so..

Kp = CO^2 O2 / (CO2)^2

Kp = (0.176^2)(0.088) / (0.824^2) =0.0040

T = 3000

Assume 1 atm for CO2, after % dissociation

P-CO2 left = 1*(1-54.8/100)= 0.452

P-CO formed = 1-0.452= 0.548

P-O2 = (1-0.452)/2 = 0.274

so..

Kp = CO^2 O2 / (CO2)^2

Kp = (0.548^2)(0.274) / (0.452^2) =0.4027

Explanation:

6 0
3 years ago
Light rays enter a translucent material what happening to the light rays
artcher [175]

When this happens, light changes speed and the light ray bends, either toward or away from what we call the normal line, an imaginary straight line that runs perpendicular to the surface of the object.

6 0
3 years ago
Blue vitriol is commonly used in industrial dyeing processes. what is the chemical formula for blue vitriol, whose systematic na
fredd [130]
CuSO₄·5H₂O the pentahydrate is the most common form

[Cu(H₂O)₄]SO₄·H₂O → [Cu(H₂O)₄]²⁺ + SO₄²⁻ + H₂O
                                        blue
6 0
3 years ago
Read 2 more answers
Other questions:
  • Is the flame test a test for the cation (metal listed first) or the anion (nonmetal listed second)?
    5·1 answer
  • The organic compounds that are structural elements in the cell walls of plants and bacteria are known as
    9·1 answer
  • As a temperature of Lava increases, ___________.
    7·2 answers
  • What would you multiply "moles of oxygen" by to get the units "grams of oxygen"?
    12·1 answer
  • Complete the sentence!
    5·2 answers
  • How do you identify whether a solution is a buffer solution or not
    9·1 answer
  • Do you think the video game "Minecraft" will ever die?
    8·2 answers
  • What did I do wrong?
    12·1 answer
  • PLEASE HELP ME!!!!! I NEED REAL HELP PLEASE I KEEP GETTING NON REAL ANSWERS!!
    15·1 answer
  • Taylor has a mass or 500 grams
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!