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3 years ago

If a solution process is exothermic, how does the energy required for dissolving the solute compare with the energy released?

1 answer:

8 0

The correct answer would be the third option. If a solution process is exothermic, the energy required is less than the energy released. An exothermic reaction is a reaction that releases energy to the surroundings. The energy released should be more than what is absorbed in order to maintain the reaction.

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Which choice contains a FALSE statment? A. For the vaporization of liquid benzene ΔH is positive. B. For the formation of 1 mol

ser-zykov [4K]

Answer:

B is False

Explanation:

In physical chemistry we always look from system's perspective, so if we heat something ΔH is positive and if the system gives heat out then ΔH is negative.

A. We have to give energy to benzene to evaporate it. Statement true.

B. If heat is absorbed then the enthalpy must be positive.

C. The heat is absorbed then ΔH is positive.

D. Usually for burning heat is exposed from system. So enthalpy is negative.

E. Obvious

7 0

3 years ago

Even though lead is toxic, lead compounds were used in ancient times as white pigments in cosmetics. What is the percentage of l

Gekata [30.6K]

<u>Answer:</u> The mass percent of lead in lead (IV) carbonate is 63.32 %

<u>Explanation:</u>

The given chemical formula of lead (IV) carbonate is $Pb(CO_3)_2$

To calculate the mass percentage of lead in lead (IV) carbonate, we use the equation:

$\text{Mass percent of lead}=\frac{\text{Mass of lead}}{\text{Mass of lead (IV) carbonate}}\times 100$

Mass of lead = (1 × 207.2) = 207.2 g

Mass of lead (IV) carbonate = [(1 × 207.2) + (2 × 12) + (6 × 16)] = 327.2 g

Putting values in above equation, we get:

$\text{Mass percent of lead}=\frac{207.2g}{327.2g}\times 0100=63.32\%$

Hence, the mass percent of lead in lead (IV) carbonate is 63.32 %

4 0

3 years ago

Why are scientific models important in the study of science? A. They are useful only for teaching students about science. B. The

madreJ [45]

The correct answer should be B.
The correct answer would be B.

4 0

3 years ago

Read 2 more answers

Determine the freezing point and boiling point of a solution that has 68.4 g of sucrose

Ymorist [56]

Answer:

Freezing T° of solution = - 3.72°C

Boiling T° of solution = 101.02°C

Explanation:

To solve this we apply colligative properties. Firstly, freezing point depression:

ΔT = Kf . m . i

ΔT = Freezing T° of pure solvent - Freezing T° of solution

Kf = Cryoscopic constant, for water is 1.86 °C/m

m = molality (moles of solute in 1kg of solvent)

i = Ions dissolved in solution

Our solute is sucrose, an organic compound so no ions are defined. i = 1.

Let's determine the moles: 68.4 g . 1mol/ 342g = 0.2 moles

molality = 0.2 mol / 0.1kg of water = 2 m

We replace data: ΔT = 1.86°C/m . 2m . 1

Freezing T° of solution = - 3.72°C

Now, we apply elevation of boiling point: ΔT = Kb . m . i

ΔT = Boiling T° of solution - Boiling T° of pure solvent

Kf = Ebulloscopic constant, for water is 0.512 °C/m

We replace:

Boiling T° of solution - Boiling T° of pure solvent = 0.512 °C/m . 2 . 1

Boiling T° of solution = 0.512 °C/m . 2 . 1 + 100°C → 101.02°C

6 0

2 years ago

Determine the number of grams in each of the quantities<br><br> 1.39.0 x 1024 molecules Cl2

STatiana [176]

Mass of Cl₂ : 164.01 g

<h3>Further explanation</h3>

A mole is a number of particles(atoms, molecules, ions) in a substance

This refers to the atomic total of the 12 gr C-12 which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

mol Cl₂ :

$\tt n=\dfrac{N}{No}\\\\n=\dfrac{1.39.10^{24}}{6.02.10^{23}}\\\\n=2.31$

mass Cl₂(MW=71 g/mol) :

$\tt mass=mol\times MW\\\\mass=2.31\times 71=164.01$

8 0

3 years ago