Answer:
a. Heat is often absorbed during reactions.
c. Heat is often released during chemical reactions.
Explanation:
Thermochemistry -
The study of thermochemistry involve the change in the amount of heat , during any physical or chemical process , is referred to as thermodynamics .
The focus of thermochemistry is on the changing amount of energy in the form of heat , on the system with respect to the surroundings .
The process like boiling , melting , sublimation , may require energy or releases energy , and hence are studied under thermochemistry .
Hence , from the given question ,
The correct options are - a , c.
Answer:
Hydrogen
Explanation:
Just to provide some background, an element is a pure substance consisting of only one type of atom. An atom is the smallest constituent of matter. All elements are comprised of a single type of atom (e.g., gold is composed of gold atoms, helium of helium atoms, phosphorus phosphorus, and so on).
A molecule is a group of two or more atoms. They can be the same atom (homonuclear), such as or different atoms (heteronuclear).
Some examples of homonuclear molecules include:
Hydrogen (H2)
Nitrogen (N2)
Phosphorus (P4)
Some examples of heteronuclear molecules include:
Carbon dioxide (CO2)
Sulfuric acid (H2SO4)
Methane (CH4)
<u>Answer</u>:
By tracking oxidation numbers we can identify the number electron in the atom
<u>Explanation</u>:
Tracking of electrons helps us to know when and how many electrons get transferred from one atom to other atom . Oxidation referred as the “loss of one or more electrons” by an atom. When the oxidation number of an element increases, there is a loss of electrons and that element is being oxidized. Oxidation numbers are usually written with the sign (+plus or −minus) followed by the magnitude, which is the opposite of charges on ions. In their elemental stage oxidation number of an atom is zero.
Answer:
2Na⁺ (aq) and 2OH⁻(aq)
Explanation:
Spectator ions:
Spectator ions are those ions which are same on both side of chemical reaction. These ions are same in the reactant side and product side. Their presence can not effect the chemical equilibrium that's why when we write the net ionic equation these ions are neglect or omitted.
Given ionic equation:
Ba⁺²(aq) + 2OH⁻(aq) + 2Na⁺ (aq) + CO²⁻₃(aq) → BaCO₃(s) + + 2Na⁺ (aq) + 2OH⁻(aq)
In given ionic equation by omitting the spectator ions i.e, 2Na⁺ (aq) and 2OH⁻(aq) net ionic equation can be written as,
Net ionic equation:
Ba⁺²(aq) + CO²⁻₃(aq) → BaCO₃(s)
B) oxygen, because oxygen is the only element that is in both chemical formulas.
