The following does NOT indicate that a chemical change
may have taken place is fracture formation. A chemical change happens when the
substance changes its physical state and composition resulting from a chemical
reaction. This chemical reaction may either give off or absorb energy. A change
in color is a chemical change. For example, litmus paper turns to red when
placed in an acid solution. Production of gas is a chemical change. For
example, adding hydrochloric acid to the tiles of the bathroom gives a hissing
sound with gases given off. Formation of a precipitate is also a chemical
change. Change in shape is not a chemical change.
<span> </span>
Answer:
the 3rd one (0.01 cm the one selected already)
Explanation:
copper wire isn't excessively big, and it wraps around the pencil because its malleable. I think that the most accurate would be 0.01 cm
Which of these measurements is expressed as three significant figures?
C. 4.20 g
Explanation:
To delineate the the nature of the bonds that would be formed between the two elements, let us first write the electronic configuration of the two species;
Be = 2, 2
F = 2, 7
Beryllium is a metal with two valence electrons whereas fluorine is a halogen with seven valence electrons.
When Be loses two electrons it becomes isoelectronic with He;
Be → Be²⁺ + 2e⁻
Also, when fluorine gains an electron, it becomes isoelectronic with Ne;
F + e⁻ → F⁻
This loss and gain of electrons between the two elements creates an electrostatic attraction them and they enter into an electrovalent bond.
Hence;
Be²⁺ + 2F⁻ → BeF₂
