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Nookie1986 [14]
3 years ago
14

Which best describes a compound such as magnesium oxide? an impure substance that is made up of two elements a mixture of two un

common substances a mixture of two common elements a pure substance that is made up of different elements
Chemistry
2 answers:
AURORKA [14]3 years ago
8 0

Answer:

A pure substance that is made up of different elements

Explanation:

kirza4 [7]3 years ago
6 0

Answer:

<u>D. a pure substance that is made up of different elements</u>

Explanation:

Step-by-step explanation:

There are two types of pure substances: elements and compounds.

Elements are made up of only one type of atom. And compounds are pure substances, that are made up of more than one type of element. Like - magnesium oxide. It is a compound of a metal with a non-metal and is held together with ionic bonds.

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Which of the following describes an energy transformation from chemical to electrical to light energy?
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The answer is B. a flashlight uses a battery to operate.

The battery represents the chemical energy. This is converted into electricity, which is converted into light energy.

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2 years ago
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Determine the number of protons, electrons, neutrons, valence electrons and valency in Oxygen atom (O) and Oxide ion (O2-). Comp
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Answer:

<em />

<em>                    Atom (O)           Ion (O²⁻)</em>

<em>Protons             8                       8</em>

<em>Electrons          8                      10</em>

<em>Neutrons          8                       8   </em>      ← only for the oxygen-16 isotope.

* The number of neutrons depends on the specific isotope. It is equal to the mass number of the isotope less the number of protons.

Explanation:

<em>Oxygen</em> is the element with atomic number 8. That means that the oxygen atoms have 8 protons.

Protons have relative positive charge equal to +1 and electrons have relative negative charge -1: same magnitude opposite sign.

Thus, the neutral oxygen, O, has also 8 electrons and 8 protons.

As per the number neutrons it depends on the specific isotope.

The isotopes are identified by the mass number, which is the number of protons plus neutrons. For instance, oxygen-16 isotope has mass number 16, 8 protons and 8 neutrons, while oxygen-15 isotope has mass number 15, 8 protons and 7 neutrons.

Oxide ion O²⁻ is the oxygen ion with -2 charge, meaning that it has 2 more electrons than protons. Then, it has 8 protons and 10 electrons, again the number of neutrons depend of the specific isotope.

The stability of an atoms or ion refers to its trend to remain in the same state or react to form another species. The ions O²⁻ are less stable than the neutral atoms O, because the negative charge will be attracted to any positive ion so ti will react faster than the neutral oxygen atom (O).

8 0
3 years ago
An aqueous solution containing 17.5 g of an unknown molecular (nonelectrolyte) compound in 100.0 g of water has a freezing point
Sonbull [250]

Answer:

molar mass = 180.833 g/mol

Explanation:

  • mass sln = mass solute + mass solvent

∴  solute: unknown molecular (nonelectrolyte)

∴ solvent: water

∴ mass solute = 17.5 g

∴ mass solvent =  100.0 g = 0.1 Kg

⇒ mass sln = 117.5 g

freezing point:

  • ΔTc = - Kc×m

∴ ΔTc = -1.8 °C

∴ Kc H2O = 1.86 °C.Kg/mol

∴ m: molality (mol solute/Kg solvent)

⇒ m = ( - 1.8 °C)/( - 1.86 °C.Kg/mol)

⇒ m = 0.9677 mol solute/Kg solvent

  • molar mass (Mw) [=] g/mol

∴ mol solute = ( m )×(Kg solvent)

⇒ mol solute = ( 0.9677 mol/Kg) × ( 0.100 Kg H2O )

⇒ mol solute = 0.09677 mol

⇒ Mw solute = ( 17.5 g ) / ( 0.09677 mol )

⇒ Mw solute = 180.833 g/mol

6 0
3 years ago
A plant was placed in the corner of a room away from a window. What might you observe about the plant after five days?
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Answer:

1. A. The plant leans toward window.

Explanation:

Plants need light to perform photosynthesis and live. Therefore, this means the plant will always lean toward light in order to survive.

- Hope that helps! Please let me know if you need further explanation.

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Which law is based on the graph that is shown below?
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Answer:

Boyle's Law

Explanation:

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