CHEMISTRY HIGH SCHOOL

Which of the following can only be separated into two or more pure substances by a chemical change?a. an element
b. a compound
c. a homogeneous mixture
d. a heterogeneous mixture

Answers

Answer 1
Answer: The best answer to the question that is being presented above would be letter b. A compound can only be separated into two or more pure substances by a chemical change. Mixtures can be separated without chemical change. 

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What is an intramolecular force?Answer: A force acting between the atoms within a molecule

Answers

Answer:

no tengo la menor idea de que es

What is the name of the binary compound Mg3 (PO3)2? A. magnesium phosphate B. magnesium phosphide C. Tri magnesium diphosphite D. magnesium phosphite

Answers

The correct option is D.

Another way to write the chemical formula of magnesium phosphite is Mg3O6P2. The compound is made up of three atoms of magnesium, six atoms of oxygen and two atoms of phosphorus. The compound has anti fungal properties and it is also used as fertilizer. The compound is partially soluble in waster and it can be yellow or green in color.

Which of the following statements is true of the critical temperature of a pure substance?A. The critical temperature is the temperature above which the liquid phase of a pure substance can exist.
B. The critical temperature is the temperature above which the liquid phase of a pure substance cannot exist.
C. The critical temperature is the temperature below which the liquid phase of a pure substance cannot exist.
D. The critical temperature is the temperature at which all three phases can coexist.
E. The critical temperature is the temperature at which the pure substance reaches, but cannot go beyond, the critical pressure.
Can someone explain this one?

Answers

B
After temperature reaches certain treshold the difference between density of liquid and gas state disappears, and it is impossible to liquify the substance.

Answer:what do u mean tho

Explanation:

what is the total number of joules released when a 5.00 gram sample of water changes from liquid to solid at 0°C ?

Answers

The heat associated with a change of physical state of a system is: Q = m\cdot l (being "l" the latent heat of state change).

Q = 5\ g\cdot 334(J)/(g) = \bf 1,67\cdot 10^(3)\ J

At 25 °c, only 0.0640 mol of the generic salt ab is soluble in 1.00 l of water. what is the ksp of the salt at 25 °c? ab(s)â½âââa+(aq)+bâ(aq)

Answers

Answer: 4.09* 10^(-3)

Explanation:

Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as

The equation for the ionization of the  is given as:

AB\rightarrow A^++B^-

Molar concentration = (moles)/(Volume)=(0.0640)/(1.00L)=0.0640M

By stoichiometry of the reaction:

1 mole of  AB gives 1 mole of A^+ and 1 mole of B^-

When the solubility of  AB is S moles/liter, then the solubility of A^+  will be S moles\liter and solubility of B^- will be S moles/liter.

K_(sp)=[A^(+)][B^(-)]

K_(sp)=[0.0640][0.0640]=4.09* 10^(-3)

Thus K_(sp) of the salt at 25^0C is 4.09* 10^(-3)

In the last 100 years, the level of CO2 in the atmosphere has been significantly increased by man by: pesticides the burning of fossil fuels domestic heat incineration of waste products

Answers

The major contributor of CO2 in the atmosphere which has a human source is the burning of fossil fuels - this is the correct answer. This is especially serious concern since the industrialization, but also includes heating with coal in people's private homes.

Answer:

The correct answer is Option (2)- Burning up of fossil fuels

Explanation:

Fossils are the remnants of the ancient plants and animals that were buried millions of years ago. Those fuels that are made up of these fossilized matters are commonly termed as fossil fuel. For example, Petroleum, Coal and natural gas. These are the major source of energy.

These fossil fuels are limited in amount and are non-renewable sources of energy. These are exploited rapidly by human beings. This burning up of fossil fuels leads to the production of a large amount of Carbon dioxide (CO₂) gas that causes a significant impact on the atmosphere. The increase in the CO₂ content also leads to an increase in the global temperature of the earth.

In the last 100 years, the CO₂ level in the atmosphere has immensely increased.

Hence, the correct answer is option (2).
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