02/09/15
Unit 1:1 Introductory Concepts - Take Home Quiz Questions
1) Define chemistry and matter.
Chemistry is connected to science that deals with the identification of the substances of which matter is composed. The investigation of properties and the ways in which they interact, combine, and change. Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space.
2) Define substance, element and atom.
Substance is matter which has a specific composition and properties. Every pure element and compound is a substance. Elements are chemically the most basic substances and cannot be broken down using chemical methods. An atom is the most smallest unit of matter that has the properties of an element. The nucleus, composed of protons and neutrons, is at the center of an atom.
3) Define mixture, homogeneous and heterogenous.
A mixture is when everything is combined into one. Homogeneous is a material science that refers to substances and mixtures which are in a single phase. This is the contrast to a substance that is heterogeneous. Heterogeneous and homogeneous are referred to mixtures of materials in chemistry. The difference between heterogeneous and homogeneous mixtures is the degree at which the materials are mixed together and the uniformity of their composition.
4) Explain the difference between mass and weight.
Mass and weight are different in science. The mass of an object is a measurement of the amount of matter the object has. Weight is a measure of the force on the object caused by a gravitational field. In other words, weight is how hard gravity pulls on an object.
5) Explain the difference between a physical and chemical property.
Physical properties are those that can be observed without changing the identity of the substance. For example, the general properties of matter can be such as color, density, hardness, etc.
6) Explain the difference between a compound and a mixture.
The different substances are not chemically joined together. Each substance in the mixture keeps its own properties. The compound has properties different from the elements it contains. Each substance is easily separated from the mixture.
7) Describe the process of distillation.
Distillation is a process of separating the component substances from a liquid mixture by selective evaporation and condensation. Distillation may result in essentially complete separation, or it may be a partial separation that increases the concentration of selected components of the mixture.
8) Provide an example of a gas-gas, liquid-liquid, and solid- solid mixture. Label each mixture as homogeneous or heterogeneous.
A gas-gas mixture can be air. Air is also a homogenous. A liquid-liquid mixture can be vinegar, also homogenous. A solid-solid mixture can be concrete. Concrete is heterogenous.
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