Classify each of the following as a pure substance or a mixture:
a cheese sandwich
an iron (Fe) nail
a soft drink
propane (C3H8)
A salt substitute (KCl)
a cheese sandwich - mixture
an iron (Fe) nail - pure substance
a soft drink - mixture
propane (C3H8) - pure substance
A salt substitute (KCl) - pure substance
a cheese sandwich: mixture
an iron (Fe) nail: pure substance
a soft drink: mixture
propane (C3H8): pure substance
A salt substitute (KCl): pure substance
To classify each of the following as a pure substance or a mixture, we need to understand the definitions of pure substances and mixtures.
A pure substance is a substance that is made up of only one type of particle or molecule. It has a uniform and definite composition throughout. Pure substances can be further classified as either elements or compounds.
A mixture, on the other hand, is a combination of two or more substances that are physically mixed together. Mixtures can be further classified as either homogeneous or heterogeneous.
Let's analyze each item mentioned:
1. A cheese sandwich: A cheese sandwich is a mixture. It consists of bread, cheese, and possibly other ingredients such as condiments or vegetables. These individual components can be physically separated, indicating that it is a mixture.
2. An iron (Fe) nail: An iron nail is a pure substance. It is made up of only iron atoms (Fe). Since it consists of only one type of particle, it is a pure substance, specifically an element.
3. A soft drink: A soft drink is a mixture. It typically consists of water, sugars, flavorings, carbon dioxide, and other additives. These different components can be physically separated, indicating that it is a mixture.
4. Propane (C3H8): Propane is a pure substance. It is a hydrocarbon compound composed of carbon and hydrogen atoms (C3H8). Since it consists of only one type of molecule, it is a pure substance, specifically a compound.
5. A salt substitute (KCl): A salt substitute is a pure substance. It is composed of only potassium (K) and chlorine (Cl) atoms, forming potassium chloride (KCl). Therefore, it is a pure substance, specifically a compound.
By analyzing the composition and properties of each item, we can determine whether it is a pure substance or a mixture.