Question

(choose 2) caco3 is which of the following: *
pure substance
mixture
compound
element
homogenous
heterogenous

(choose 2) cu is which of the following: *
pure substance
mixture
compound
element
homogenous
heterogenous

(choose 2) h2o is which of the following: *
pure substance
mixture
compound
element
homogenous
heterogenous

Explanation:

• For \(CaCO_3\):
• A pure substance has a definite composition. \(CaCO_3\) (calcium carbonate) has a fixed chemical formula, so it is a pure substance.
• A compound is a pure substance composed of two or more different elements chemically combined. \(CaCO_3\) is composed of calcium (\(Ca\)), carbon (\(C\)), and oxygen (\(O\)) elements, so it is a compound.
• For \(Cu\):
• A pure substance has a definite composition. Copper (\(Cu\)) has a fixed chemical identity, so it is a pure substance.
• An element is a pure substance that cannot be broken down into simpler substances by chemical means. \(Cu\) is an element as it consists of only copper atoms.
• For \(H_2O\):
• A pure substance has a definite composition. Water (\(H_2O\)) has a fixed chemical formula, so it is a pure substance.
• A compound is a pure substance composed of two or more different elements chemically combined. \(H_2O\) is composed of hydrogen (\(H\)) and oxygen (\(O\)) elements, so it is a compound.

Answer:

• For \(CaCO_3\): Pure Substance, Compound
• For \(Cu\): Pure Substance, Element
• For \(H_2O\): Pure Substance, Compound