Use the following equations to answer the next five questions:
i. h2o --> h2o
ii. na+ + cl- ag+ + no3- --> agcl + na+ + no3-
iii. ch3oh + o2 --> co2 + h2o
iv. 2h2o --> 2h2 + o2
v. h+ + oh- --> h2o
(a) which equations describes a physical change?
(b) which equation identifies the reactants and products of a combustion reaction?
(c) which equation is not balanced?
(d) which is a net ionic equation?

(a) i

(b) iii

(c) iii

(d) v

Explanation:

(a) A physical change does not alter the identity of the substance. Here the water remains water, but may change undergo a physical change such as vaporization or freezing.

(b) A combustion reaction usually involves the exothermic reaction of oxygen with another molecule to form carbon dioxide and water

(c) The reaction may be balanced as follows: CH₃OH + 3/2O₂ ⇒ CO₂ + 2H₂O

(d) A net ionic equation only takes into account the species that underwent a chemical change. Equation ii. for example, is not a net ionic equation because the Na⁺ and NO₃⁻ did not change in any way.

h let me think

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation: