Does each of these describe a physical change or a chemical change? explain a. the moth balls gradually vaporize in a closet. hydrofluoric acid attacks class, and is used to etch calibrations marks on glass laboratory utensils a french chef making a sauce with brandy is able to burn of the alcohol from the brandy leaving just the brandy flavoring d. chemistry majors sometimes et holes in the cotton jeans they wear to lab, because of acid spills a piece of egg boiled in water for 20 minutes

a. The mothballs gradually vaporize in a closet. Physical change

b. Hydrofluoric acid attacks glass, and is used to etch calibrations marks on glass laboratory utensils. Chemical change

c. A French chef making a sauce with brandy is able to burn of the alcohol from the brandy leaving just the brandy flavoring. Chemical change

d. Chemistry majors sometimes et holes in the cotton jeans they wear to lab, because of acid spills. Chemical change

e. A piece of egg boiled in water for 20 minutes. Chemical change

Explanation:

In a physical change, there is no change in the chemical composition of the substance, the change is only on the physical properties. For example, state changes (a).

In a chemical change instead, usually there is a combination of two or more substances that combine to form a new one different from the originals. For example, chemical reactions like combustion (c) or protein denaturalization (e). The attacking of hydrofluoric acid to glass (b) or the acid pill attacking cotton are chemical reactions too (d).

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.