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Contact [7]
3 years ago
10

How is enthalpy used to predict whether a reaction is endothermic or exothermic?

Chemistry
1 answer:
Black_prince [1.1K]3 years ago
8 0
When the enthalpy change of the reaction is positive, the reaction is exothermic. 
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In a liquid-liquid extraction, how can you experimentally tell which layer is organic and which layer is aqueous? Can you always
zysi [14]

Answer:

Explanation:

Liquid-liquid extraction is a very useful method to separate components from a mixture. It consists of separating one or several substances dissolved in a solvent by transferring them to another solvent insoluble or partially insoluble in the first. The transfer of matter is achieved by direct contact between the two liquid phases.

For the extraction process, the solution is placed in a separating funnel, a water-immiscible organic solvent is added (ethyl ether is the most used), the solution with the compound to be separated, the funnel is covered and the funnel is top. Then it shakes. Depending on the solubilities and density, different layers are observed. The denser the compound, the more it will sink.

Since the organic compound is usually much more soluble in ether than in water, most of the organic compound will be dissolved in the ether phase (upper phase) and inorganic salts, which are not soluble in ether, will remain in the aqueous phase ( lower phase). Subsequently, by separating the separating funnel the two phases are separated, the organic phase is collected.

Occasionally, after stirring, the two immiscible liquids do not separate sharply, forming an emulsion in the intermediate zone. This is called the colloidal suspension of a liquid in another (system consisting of two or more phases, usually a liquid and another dispersed in the form of generally very fine solid particles). One of the reasons for the formation of an emulsion is when the two phases have similar densities. Then the relative density of the organic solvent and water cannot always be relied upon, although there are methods to facilitate the complete separation of the two phases.

7 0
3 years ago
Please help me find the final answer
dlinn [17]

Answer:

5. The mass of Na₂CO₃, that will produce 5 g of CO₂ is approximately 12.04 grams of Na₂CO₃

6. The mass of nitrogen gas (N₂) that will react completely with 150 g of hydrogen (H₂) in the production of NH₃ is 693.\overline{3168} grams of N₂

Explanation:

5. The given equation for the formation of carbon dioxide (CO₂) from sodium bicarbonate (Na₂CO₃)  is presented as follows;

(Na₂CO₃) + 2HCl → 2NaCl + CO₂ + H₂O

One mole (105.99 g) of Na₂CO₃ produces 1 mole (44.01 g) of CO₂

The mass, 'x' g of Na₂CO₃, that will produce 5 g of CO₂ is given by the law of definite proportions as follows;

\dfrac{x \ g}{105.99 \ g} = \dfrac{5 \ g}{44.01 \ g}

\therefore {x \ g} = \dfrac{5 \ g}{44.01 \ g} \times 105.99 \ g \approx 12.04 \ g

The mass of Na₂CO₃, that will produce 5 g of CO₂, x ≈ 12.04 g

6. The chemical equation for the reaction is presented as follows;

N₂ + 3H₂ → 2NH₃

Therefore, one mole (28.01 g) of nitrogen gas, (N₂), reacts with three moles (3 × 2.02 g) of hydrogen gas (H₂) to produce 2 moles of ammonia (NH₃)

The mass 'x' grams of nitrogen gas (N₂) that will react completely with150 g of hydrogen (H₂) in the production of NH₃ is given as follows;

\dfrac{x \ g}{28 .01 \ g} = \dfrac{150 \ g}{3 \times 2.02 \ g} = \dfrac{150 \ g}{6.06 \ g}

\therefore \ x \ g= \dfrac{150 \ g}{6.06 \ g} \times 28.01 \ g = 693.\overline {3168} \ g

The mass of nitrogen gas (N₂) that will react completely with 150 g of hydrogen (H₂) in the production of NH₃, x = 693.\overline{3168} grams

6 0
3 years ago
How many distinct and degenerate p orbitals exist in the second electron shell, where n = 2?
viktelen [127]

Answer: 3 degenerate orbitals are obtained

Explanation:

The p orbital can house a maximum of 6 electrons splitting the degenerate orbital into 3 and having each contain a maximum of 2 electrons each

8 0
4 years ago
2. A 2.75 kg sample of a substance occupies a volume of 250.0 cm^3. Find its density in g/cm.
hichkok12 [17]

Answer:

<h3>The answer is 11 g/cm³</h3>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume}  \\

From the question

mass = 2.75 kg = 2750 g

volume = 250 cm³

We have

density =   \frac{2750}{250}  \\

We have the final answer as

<h3>11 g/cm³</h3>

Hope this helps you

6 0
4 years ago
What kind of intermolecular forces act between a hydrogen cyanide (HCN) molecule and a carbon monoxide molecule?
Dahasolnce [82]

Answer:

Dispersion forces

Dipole-Dipole interaction

Explanation:

The London dispersion force refers to the temporary attractive force that acts between the electrons in two adjacent atoms when the atoms develop temporary dipoles. Dispersion forces act between any two molecules even when other intermolecular forces are in operation as long as the molecules are in close proximity to each other.

Now, CO is polar and the HCN is also polar molecule. Hence, dipole - dipole interaction forces  are also in operation and acts between the two molecules in close proximity to each other.

8 0
3 years ago
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