Question

c) how do they differ from each other? give an example of each
d) what are the two types of pure substances? _____________ and _____________
e) how do they differ from each other? give an example of each.

1. a) define the following terms:

i) physical change:
ii) chemical change:

b) what are the 5 indicators of a chemical change:
i) _______________
ii) _______________
iii) _______________
iv) _______________
v) _______________

1. identify the meaning of the following symbol and a precautionary measure that should be taken while working with this chemical

symbol	symbol meaning	precaution

Explanation:

The questions cover fundamental concepts in chemistry. Pure substances are classified into elements and compounds based on their chemical composition. Physical changes do not alter chemical identity, whereas chemical changes result in new substances, indicated by signs like color change, gas production, temperature change, precipitation, or light emission. The exclamation mark symbol is a standard GHS hazard pictogram representing acute toxicity, skin/eye irritation, or respiratory sensitization, requiring standard personal protective equipment (PPE) and ventilation.

Answer:

d) Elements and compounds.
e) Elements consist of only one type of atom and cannot be broken down chemically (e.g., Oxygen, \(O_2\)). Compounds consist of two or more different elements chemically bonded together and can be broken down into simpler substances (e.g., Water, \(H_2O\)).

1. a)

i) Physical Change: A change in which the form or state of matter is altered but no new chemical substance is formed.
ii) Chemical Change: A process where one or more substances are altered into one or more new and different substances.

b)
i) Color change
ii) Temperature change (absorption or release of heat)
iii) Production of a gas (bubbling/fizzing)
iv) Formation of a precipitate (solid forming from liquids)
v) Production of light or odor

4)

Symbol	Symbol Meaning	Precaution