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2 years ago

Chất có ở đâu ? nước tự nhiên là chất hay hỗn hợp

Chemistry

1 answer:

Lynna [10]2 years ago

4 0

Answer:

Water, H2O, is a pure substance, a compound made of hydrogen and oxygen. Although water is the most abundant substance on earth, it is rarely found naturally in its pure form. Most of the time, pure water has to be created. Pure water is called distilled water or deionized water.

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List the following elements in order of increasing number of valence electrons: C, CI, As, Na, He.

lorasvet [3.4K]

B is the correct answer

4 0

3 years ago

2. Which of the following expressions is generally used for solubility? (1 point)

miskamm [114]

Answer:

For 2: The correct answer is grams of solute per 100 grams of solvent.

For 3: The correct answer is supersaturated.

For 4: the correct answer is the solubility decreases.

Explanation:

For 2:

Solubility is defined as the property which refers to the ability of the solute that can be dissolved in a solvent. It is defined as the number of grams of solute per 100 grams of solvent.

For 3:

Unsaturated solution is defined as the solution in which amount of solute that is dissolved in the solvent is less.

Saturated solution is defined as the solution in which no more solute can be dissolved in the given amount of solvent.

Emulsion is defined as the dispersion of one liquid in another liquid in which it is not soluble.

Supersaturated solution is defined as the solution in which solvent contains more amount of solute than the required amount. These solutions help in the process of crystallization.

When a crystal is added to a supersaturated solution, more and more particles come out of the solution and this process is known as crystallization.

For 4:

According to the Henry's Law

The solubility of the gas in a liquid is directly proportional to the partial pressure of the gas.

$\text{Solubility of a gas in a liquid}\propto \text{Partial pressure of the gas}$

With increase in the partial pressure, the solubility of the gas in liquid also increases and vice-versa.

Hence, the correct answer is the solubility decreases.

7 0

2 years ago

Read 2 more answers

Which equation represents a redox reaction?

labwork [276]

Answer:

D. $2NaBr + Cl_2\rightarrow 2NaCl + Br_2$

Explanation:

Hello!

In this case, for the given set of chemical reactions, it is possible to infer that D. is a categorized as redox due to the following:

Since both chlorine and bromine remain as diatomic gases, their oxidation states in such a form is 0, but as anions with lithium cations they have a charge of - according to the following reaction and half-reactions:

$2NaBr + Cl_2\rightarrow 2NaCl + Br_2$

$Cl_2^0+2e^-\rightarrow 2Cl ^-\\\\2Br^- \rightarrow Br_2^0+2e^-$

Unlike the other reactions whereas no change in the oxidation states is evidenced.

6 0

2 years ago

Read 2 more answers

Which of the following would have the best thermal insulation properties? A. A paper cup B. a plastic cup C. a thick mug D. a cu

Vadim26 [7]

From the above options, the best Thermal insulator will be a Plastic cup.

Option (b);

Explanation

Thermal insulators resist to conduct energy or reduction of heat transfer when objects come across in contact with radiation or higher heat object. To conduct energy we need metal or those materials which contain free electrons in it to move from one metal to another.

Plastic doesn't have metallic character so it will resist the heat up to some threshold. Mostly this material is used in separating two current-conducting material. There are many other examples of thermal insulator such as Rubber, fabrics, paper, wood, wool.

6 0

2 years ago

Read 2 more answers

A hot air balloon is filled to 1250 m3 at 27 C. At what temperature will the balloon be filled to 1600 m3 if the pressure remain

SSSSS [86.1K]

Answer:

384.2 K

Explanation:

First we convert 27 °C to K:

27 °C + 273.16 = 300.16 K

With the absolute temperature we can use Charles' law to solve this problem. This law states that at constant pressure:

T₁V₂=T₂V₁

Where in this case:

T₁ = 300.16 K

V₂ = 1600 m³

T₂ = ?

V₁ = 1250 m³

We input the data:

300.16 K * 1600 m³ = T₂ * 1250 m³

And solve for T₂:

T₂ = 384.2 K

7 0

2 years ago