Question

question 6 (1 point)
which of the following processes require(s) chemical methods?
o a
separating a homogeneous mixture into pure substances.
o b
separating a heterogeneous mixture into pure substances.
o c
distilling a saltwater mixture.
o d
breaking a compound into its constituent elements.
o e
at least two of the above (a-d) require chemical methods

Explanation:

• Option a: Separating a homogeneous mixture (like a solution) into pure substances can often be done by physical methods (e.g., distillation for a salt - water solution, which is a physical change as it relies on differences in boiling points).
• Option b: Separating a heterogeneous mixture (e.g., sand and water) can be done by physical methods such as filtration (physical separation based on particle size differences).
• Option c: Distilling a salt - water mixture is a physical method (change of state from liquid to gas and back to liquid, no new substances formed chemically).
• Option d: Breaking a compound into its constituent elements requires a chemical change. For example, decomposing water ($H_2O$) into hydrogen ($H_2$) and oxygen ($O_2$) gas is a chemical reaction (bonds are broken and new substances are formed).

Answer:

d. Breaking a compound into its constituent elements.