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2 years ago

Important (question on k12 test)

Chemistry

2 answers:

monitta2 years ago

4 0

Answer:

A new Dana system of classification contains 78 different classes of minerals based on composition and then further classified by type and group. To be considered a mineral, a substance must be an inorganic, naturally formed solid, with a specific chemical formula and a fixed internal structure. To test whether something is a mineral, there are several identification tests to which the substance is subjected, including its resistance to scratching, its density in comparison to water, its color, the degree of light it reflects, the color of the powdered mineral, its breakage pattern and its crystalline form.

Explanation:

Luden [163]2 years ago

4 0

Answer: chemical makeup and crystal lattice structure

Explanation:

The minerals are the inorganic substances that are extracted beneath the earth crust. These minerals are associated with the gangue particles that are required to be removed by processing.

The minerals can be classified on the basis of the chemical and physical properties. The chemical properties define the chemical composition of the mineral. The physical properties define how minerals react with the external environment.

Thus chemical makeup and crystal lattice structure can be a useful approach to classify the minerals as the minerals may differ chemically as well as in structural makeup.

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Which best describes a compound such as sodium chloride?

finlep [7]

Answer:

It s a pure substance.

Explanation:

Can only be separated into its different elements by chemical means because it is connected by a chemical bond.

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2 years ago

Which of the following are not single-displacement reactions?

Goshia [24]

Answer:

$\boxed{\text{B and C }}$

Explanation:

In a single-displacement reaction, one element exchanges partners with another element in a compound.

$\textbf{A. } \rm Fe + 2HCl \longrightarrow FeCl_2 + H_2$

This is a single-displacement reaction, because the element Fe exchanges partners with H in HCl.

$\textbf{B. } \rm KOH + HNO_3 \longrightarrow H_2O + KNO_3$

This is not a single-displacement reaction, because it is a reaction between two compounds.

This is a double displacement reaction in which the K⁺ and H⁺ cations change partners with the anions.

$\textbf{C. } \rm Na_2S + 2HCl \longrightarrow 2NaCl + H_2S$

This is not a single-displacement reaction. It is another double displacement reaction, in which the Na⁺ and H⁺ cations change partners with the anions.

$\textbf{D. } \rm Ca + 2HOH \longrightarrow Ca(OH)_2 + H_2$

This is a single-displacement reaction, because the element Ca exchanges partners with H in H₂O.

$\boxed{\textbf{B and C }}$ are not single-displacement reactions.

6 0

2 years ago

The molecule ethylbenzene is considered an....

noname [10]

D. Cycloalkene
________________________

5 0

2 years ago

Help with this I need it right now please

alexdok [17]

Answer:

1) F=5×9.8

F=49

2) F=50×9.8

F=490

3) W= fd

W=10×3

W=30

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2 years ago

What is the frequency of radiation emitted by a photon of light if the energy released during its transition to ground state is

notka56 [123]

I cant see the units properly. You can try using E = hf, where h is the Planck's constant and f is the frequency that you need and E is the energy released in the transition.

6 0

3 years ago