Classify each of the following as an element, a compound, or a mixture: (a) iron (b) oxygen (c) mercury oxide (d) pancake syrup (e) carbon dioxide (f) a substance composed of molecules each of which contains one hydrogen atom and one chlorine atom (g) baking soda (h) baking powder
The Correct Answer and Explanation is:
Here is the classification of each substance:
(a) Iron – Element
(b) Oxygen – Element
(c) Mercury oxide – Compound
(d) Pancake syrup – Mixture
(e) Carbon dioxide – Compound
(f) A substance composed of molecules each of which contains one hydrogen atom and one chlorine atom – Compound
(g) Baking soda – Compound
(h) Baking powder – Mixture
Explanation:
Matter can be classified into elements, compounds, or mixtures, based on its composition.
Elements consist of only one type of atom. They cannot be broken down into simpler substances by chemical means.
- Iron (Fe) and oxygen (O₂) are both elements. Iron is a metal with atoms of one type, and oxygen exists naturally as O₂ molecules but still counts as a pure element.
Compounds are substances made of two or more elements chemically combined in fixed proportions. They have different properties from their component elements and can be broken down into those elements by chemical reactions.
- Mercury oxide (HgO) is made from mercury and oxygen.
- Carbon dioxide (CO₂) is made of carbon and oxygen atoms.
- The substance made of one hydrogen and one chlorine atom per molecule is hydrogen chloride (HCl), a compound.
- Baking soda is sodium bicarbonate (NaHCO₃), which is also a compound because it has multiple elements chemically bonded.
Mixtures contain two or more substances (elements or compounds) physically combined. These components retain their individual properties and can be separated by physical means.
- Pancake syrup is a mixture, often containing sugar, water, flavorings, and sometimes preservatives. These ingredients are not chemically bonded.
- Baking powder is a mixture of baking soda (a compound), an acid (such as cream of tartar), and a starch (like cornstarch). Since its components are not chemically bonded, it is a mixture.
This classification helps in understanding how substances behave and how they can be separated or changed in chemical reactions.
