The unit cm3 is used to express .?

Calcule a variação da entalpia dessa reação ( 2 NH3 (g) ---> CO(NH2)2 (s) + H2O (L) ) a partir das seguintes equações termoqu

Nitella [24]

ΔH = +438 kJ

We have three equations:

(I) N₂ + 3H₂ → 2NH₃; ΔH = -92 kJ

(II) H₂ +½O₂ → H₂O; ΔH = -286 kJ

(III) CO(NH₂)₂ + ³/₂O₂ → CO₂ + 2H₂O + N₂; ΔH = -632 kJ

From these, we must devise the target equation:

(IV) 2NH₃ + CO₂ → CO(NH₂)₂ + H₂O; ΔH = ?

_________________________________

The target equation has 2NH₃ on the left, so you reverse equation (I).

When you reverse an equation, you reverse the sign of its ΔH.

(V) 2NH₃ → N₂ + 3H₂; ΔH = +92 kJ

Equation (V) has 1N₂ on the right, and that is not in the target equation.

You need an equation with 1N₂ on the left.

Reverse Equation (III).

(VI) CO₂ + 2H₂O + N₂ → CO(NH₂)₂ + ³/₂O₂; ΔH = +632 kJ

Equation (VI) has ³/₂O₂ on the right, and that is not in the target equation.

You need ³/₂O₂ on the left.

Multiply Equation (II) by three.

When you multiply an equation by three, you multiply its ΔH by three.

(VII) 3H₂ +³/₂O₂ → 3H₂O; ΔH = -286 kJ

Now, you add equations (V), (VI), and (VII), cancelling species that appear on opposite sides of the reaction arrows.

When you add equations, you add their ΔH values.

_______________________________________

We get the target equation (IV):

(V) 2NH₃ → N₂ + 3H₂; ΔH = + 92 kJ

(VI) CO₂ + 2H₂O + N₂ → CO(NH₂)₂ + ³/₂O₂; ΔH = +632 kJ

(VII) 3H₂ +³/₂O₂ → 3H₂O; ΔH = -286 kJ

(IV) 2NH₃ + CO₂ → CO(NH₂)₂ + H₂O; ΔH = +438 kJ

7 0

2 years ago

Put the steps of the carbon cycle in order using Step 1 as your starting point. Step 1: Bacteria, through nitrogen fixation and

Amanda [17]

Answer:

The answer is explained below

Explanation:

Put the steps of the carbon cycle in order using Step 1 as your starting point

Step 1: Bacteria, through nitrogen fixation and nitrification, convert nitrogen into a usable form. The animal dies and decomposes, returning nitrogen back to the soil. Once nitrogen is in usable form, it is taken up by plants and assimilated into proteins.. An animal eats a plant and the nitrogen becomes part of the animal’s proteins.

The steps taking in the carbon circle using step 1 as the starting point is as follows:

Step 1: Bacteria, through nitrogen fixation and nitrification, convert nitrogen into a usable form.

Bacteria convert nitrogen into nitrites and nitrates through the process of nitrification. Nitrites and nitrates are in the form that can be used by the plants

Step 2: Once nitrogen is in usable form, it is taken up by plants and assimilated into proteins.

The Nitrogen can only be used by the plants when in nitrites and nitrates form. When in this form, it is then assimilated into plant tissue as protein.

Step 3: An animal eats a plant and the nitrogen becomes part of the animal’s proteins.

An animal such as rabbit eats the plant and the protein in the plant becomes protein in the animal.

Step 4: The animal dies and decomposes, returning nitrogen back to the soil.

When the animal dies, the animal undergoes decomposition and the nitrogen in the animal is returned to the soil

5 0

3 years ago

What's makes up chromatin

tankabanditka [31]

Answer:

histones

Explanation:

8 0

3 years ago

Improper or incomplete usage of citations can lead to

lys-0071 [83]

Improper or incomplete usage of citations can lead to plagiarism.

Without proper usage of citations, teachers or whoever is looking over your work, may think because you do not hold acceptable citations, that they will think it is plagiarized. Plagiarism is taking another person's work or ideas without citing it. Citation or direct quotation could save you from plagiarism.

5 0

3 years ago

Read 2 more answers

Which of the following methods correctly describes the preparation of 1.00 L of an aqueous solution of 0.500 M NaOH?

djyliett [7]

Answer:

Place 20.0 g NaOH(s) in a flask and dilute to 1.00 L with water.

Explanation:

7 0

2 years ago