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
sergij07 [2.7K]
2 years ago
9

A scientist measures the standard enthalpy change for the following reaction to be 67.9 kJ:

Chemistry
1 answer:
hodyreva [135]2 years ago
6 0

Answer:

-252.5 kJ/mol = ΔH H2O(g)

Explanation:

ΔH Fe2O3 = -825.5kJ/mol

ΔH H2 = 0kJ/mol

ΔH Fe = 0kJ/mol

Based on Hess's law, ΔH of a reaction is the sum of ΔH of products - ΔH of reactants. For the reaction:

Fe2O3(s) + 3 H2(g) →2Fe(s) + 3 H2O(g)

ΔHr = 67.9kJ/mol = 3*ΔH H2O + 2*ΔHFe - (ΔH Fe2O3 + 3*Δ H2)

67.9kJ/mol = 3*ΔH H2O + 2*0kJ/mol - (ΔH -825.5kJ/mol + 3*Δ H2)

67.9 = 3*ΔH H2O(g) + 825.5kJ/mol

-757.6kJ/mol = 3*ΔH H2O(g)

<h3>-252.5 kJ/mol = ΔH H2O(g)</h3>
You might be interested in
A 0.5438 g of a C.H.O. compound was combusted in air to make 1.039 g of CO2 and 0.6369 g H20. What is the empirical formula? Bal
goblinko [34]

Answer:

C₃H₅O₂

4C₃H₅O₂ + 13O₂ → 12CO₂ + 10H₂O

Explanation:

The reaction can be expressed as:

CₓHₓOₓ + nO₂ → CO₂ + H₂O

Under the assumption that there was a total combustion, all of the carbon in the reactant was combusted into CO₂, so <u>the mass of C contained in the C.H.O. compound is the same mass of C contained in 1.039 g of CO₂</u>:

1.039gCO_{2}*\frac{1molCO_{2}}{44gCO_{2}} *\frac{1molC}{1molCO_{2}} *\frac{12gC}{1molC} =0.2834gC

All of the hydrogens atoms in the compound ended up becoming H₂O, so <u>the mass of H contained in the C.H.O. compound is the same mass of H contained in 0.6369 g of H₂O</u>:

0.6369g*\frac{1molH_{2}O}{18gH_{2}O} *\frac{1molH}{1molH_{2}O} *\frac{1gH}{1molH} =0.0354gH

Because the compound is composed only by C, H and O, <u>the mass of O in the compound can be calculated by substraction</u>:

0.5438 g Compound - 0.2834 g C - 0.0354 g H = 0.2250 g O

In order to determine the empirical formula, we calculate the moles of each component:

  • mol C = 0.2834 g C ÷ 12 g/mol = 0.0236 mol C
  • mol H = 0.0354 g H ÷ 1 g/mol = 0.0354 mol H
  • mol O = 0.2250 g O ÷ 16 g/mol = 0.0141 mol O

Then we divide those values by the lowest one:

0.0236 mol C ÷ 0.0141 = 1.67

0.0354 mol H ÷ 0.0141 = 2.51

0.0141 mol O ÷ 0.0141 = 1

If we multiply those values by 2, we're left with the empirical formula C₃H₅O₂.

  • The reaction is:

4C₃H₅O₂ + 13O₂ → 12CO₂ + 10H₂O

8 0
3 years ago
How is the weathering of rocks by water different from the weathering of rocks by ice?
andrey2020 [161]

Answer:

It is because water is liquid and it can be weathered easily. While weathering by solid is a bit dangerous because of its hardness.

Explanation:

4 0
2 years ago
Explain what keeps the electrons confined in the space surrounding the nucleus
vitfil [10]

Answer:

Electrons are trapped inside the atom because of the attraction forces with positively charged protons that are found in the nucleus.

8 0
2 years ago
An ionic bond is best described as
LekaFEV [45]
The answer would be B the transfer of electrons from one atom to another
6 0
3 years ago
Read 2 more answers
The missing components in the table to the right are indicated with orange letters. Complete table by filling in the correspondi
V125BC [204]

Answer :

A = In

B = 27

C = 73

D = 49

E = 56

F = 54

G = 66

H = 108

I = 32

Explanation :

Atomic number is defined as the number of protons or number of electrons.

Atomic number = number of protons = number of electrons

Mass number is defined as the sum of number of protons and number of neutrons.

Number of neutrons = Mass number - Number of protons

Number of electrons = Number of protons - charge

Element        Number of       Number of        Number of        Atomic

symbol          protons            electrons          neutrons           mass

  Co                  27                     27                      31                    58

  In                    49                     49                     66                   115

  Ta                   73                     73                     108                  181

  Ba²⁺                56                    54                      81                   137

  S²⁻                  16                      18                      16                    32

4 0
3 years ago
Other questions:
  • You measure out 14.66 mL of vinegar solution. You used 13.58 mL of 0.115 M NaOH solution to titrations to the endpoint. What wha
    12·1 answer
  • Of the elements: b, c, f, li, and na. the element with the highest ionization energy is
    5·1 answer
  • What would be the temperature change 3.0 g of water absorbed 15 J of heat
    15·1 answer
  • The decomposition reaction of N2O5 in carbon tetrachloride is 2N2O5−→−4NO2+O2. The rate law is first order in N2O5. At 64 °C the
    6·2 answers
  • If the detector is capturing 3.3×108 photons per second at this wavelength, what is the total energy of the photons detected in
    9·1 answer
  • Question 18The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the ga
    7·1 answer
  • This is due today so please help me
    8·2 answers
  • What will happen to the pH of a solution when the [H+] is increased?
    12·1 answer
  • Sa se calculeze presiunea exercitata de 2 moli de h2 într un vas cu vol de 10l la temperatura de 27gc
    14·1 answer
  • 1. The transfer of _____ in the form of _____
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!