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
VikaD [51]
3 years ago
8

Given the following data:

Chemistry
1 answer:
bagirrra123 [75]3 years ago
3 0

176.0 \; \text{kJ} \cdot \text{mol}^{-1}

As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its \Delta H can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.

Let the three equations with \Delta H given be denoted as (1), (2), (3), and the last equation (4). Let a, b, and c be letters such that a \times (1) + b \times (2) + c \times (3) = (4). This relationship shall hold for all chemicals involved.

There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, 3 + (-1) = 2 shall resemble the number of \text{H}_2 left on the product side when the second equation is directly added to the third. Similarly

  • \text{NH}_4 \text{Cl} \; (s): -2 \; a = 1
  • \text{NH}_3\; (g): -2 \; b = -1
  • \text{HCl} \; (g): 2 \; c = -1

Thus

a = -1/2\\b = 1/2\\c = -1/2 and

-\frac{1}{2} \times (1) + \frac{1}{2} \times (2) - \frac{1}{2} \times (3)= (4)

Verify this conclusion against a fourth species involved- \text{N}_2 \; (g) for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.

a + b = -1/2 + 1/2 = 0

Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.

\Delta H _{(4)} = -\frac{1}{2} \; \Delta H _{(1)} + \frac{1}{2} \; \Delta H _{(2)} - \frac{1}{2} \; \Delta H _{(3)}\\\phantom{\Delta H _{(4)}} = -\frac{1}{2} \times (-628.9)+ \frac{1}{2} \times (-92.2) - \frac{1}{2} \times (184.7) \\\phantom{\Delta H _{(4)}} = 176.0 \; \text{kJ} \cdot \text{mol}^{-1}

You might be interested in
What is the structure of epithelial cells?
EleoNora [17]
Your answer is C for sure
5 0
2 years ago
Give the name of this alcohol.
solong [7]

Answer:

An alcohol is an organic compound with a hydroxyl (OH) functional group on an aliphatic carbon atom. Because OH is the functional group of all alcohols, we often represent alcohols by the general formula ROH, where R is an alkyl group. Alcohols are common in nature.

Explanation:

3 0
2 years ago
If 156 grams of chromium react with an excess of oxygen, as shown in the balanced chemical equation below, how many grams of chr
Sunny_sXe [5.5K]

Answer:

=759.95 grams.

Explanation:

The molar mass of chromium is 51.9961 g/mol

Therefore the number of moles of chromium in 156 grams is:

Number of moles =mass/RAM

=156g/51.9961g/mol

=3 moles.

From the equation provided, 3 moles of chromium metal produce 2 moles of Chromium oxide.

Therefore 3 moles of chromium produce:

(3×2)/4 moles =1.5 moles of chromium oxide.

I mole of chromium oxide has a mass of 151.99 g

Thus 1.5 moles= 1.5mole ×151.99 g/mol

=759.95 grams.

3 0
2 years ago
126785033% Divided by 348675948849 = <br> what does it equal
meriva

Answer:

0.00000363618

could be wrong.

double check me someone or just trust me

(don't blame me if you get it wrong)

5 0
3 years ago
Directions Now that the lab is complete, it is time to write your lab report. The purpose of this guide is to help you write a c
Elza [17]

Answer:

foot

Explanation:

6 0
2 years ago
Other questions:
  • In what unit is formula mass expressed?
    5·1 answer
  • Please help me do this question.
    11·1 answer
  • Treatment of 2,4,6-tri-tert-butylphenol with bromine in cold acetic acid gives the compound C18H29BrO in quantitative yield. The
    8·1 answer
  • The elements in groups 3-12 are known as:
    15·1 answer
  • Assume that the NO, concentration in a house with a gas stove is 150 pg/m°. Calculate the equivalent concentration in ppm at STP
    11·1 answer
  • Which of these substances are molecules?
    6·1 answer
  • Why do compounds have different conductivity values if they are the same type of compound?
    14·1 answer
  • Which term is the rate at which work is done <br><br><br><br><br><br> Answer: power
    10·1 answer
  • chlorine reacts with fluorine to form flowing monofluoride write an equation for this reaction including the state symbols are t
    15·1 answer
  • Consider the hypothetical atom x. if the molecular formula for calcium nitrate is ca(no3)2 and the formula of x chloride is xcl2
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!