Answer: The given statement is false.
Explanation:
A chemical reaction is a reaction which brings change in chemical composition of reactants resulting in formation of new compounds which have different chemical properties.
For example,
So, when gas is produced in a chemical reaction then it means new compounds are formed due to breakage of old bonds and formation of new bonds.
Thus, we can conclude that the given statement gas produced from a reaction is a phase change and not a chemical change, is false.
B. Elements produce continuous spectra.
C. Elements produce spectra with only a few distinct lines.
Atomic emission spectra are unique to each element and consist of distinct lines representing different energy levels.
The correct statement regarding atomic emission spectra is option C: Elements produce spectra with only a few distinct lines.
#SPJ6
Valence electrons are the electrons located in an atom's outermost shell. They play a critical role in chemical bonding and reactions and determine the atom's reactivity and placement in the Periodic Table.
The electrons located in the outermost shell of an atom are correctly referred to as valence electrons. These electrons play a crucial role in chemical bonding and reactions because they are the most distant from the atom's nucleus and thus, the most loosely bound, making them available for interactions with other atoms. For instance, when atoms interact to form a chemical bond, the valence electrons are often the ones that are shared, transferred, or involved in the bond formation. The number of valence electrons in an atom also determines the atom's reactivity and its placement in the Periodic Table.
#SPJ11
Answer:
The ionic compound NaCl has a Face Centered Cubic unit cell
The site for atoms are Face, center and Edges corner.
Effective number of atoms
Na+
1centers + 12edges x = 4 Na+
Cl-
6face x + x8 corners = 4Cl-
This is just one unit cell effective atom, there are thousand's of such unit cells are combined to form one such structure of NaCl. The real formula of NaCl is Na4Cl4 but for simplicity we use empirical formula that is NaCl.
b. esophagus
c. intestines
d. heart
The correct option is D.
Significant figure refers to the number of digits that are used to report a measured quantity. The amount of a significant number in a measurement always equal to the number of digits that are known with some degree of confidence and the last number, which is usually an estimate. When carrying out calculations with significant figures measurements, one must be careful to report the number of significant figure to reflect the least precise measurement.