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.

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.