Which of the following statements is NOT true? A. Covalent compounds are often gases or liquids.
B. Covalent bonds occur between nonmetals.
C. Covalent compounds have low melting and boiling points.
D. Covalent bonds between atoms of a compound are relatively weak compared to bonds between molecules.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

16

explanation:

the marks go by 4s

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