Chemistry Notes
Mastering Chemistry Chapter 1 Notes:
Mixtures, Solutions, Pure Chemical Substances, Compounds, and Elements
Matter can be classified into several categories.
All substances are either pure chemical substances or mixtures. Mixtures can be separated into their component parts through physical means, whereas pure chemical substances require chemical or nuclear reactions to separate them.
Pure chemical substances can be further divided into elements or compounds.
Mixtures can be either heterogeneous orhomogeneous. Homogeneous mixtures are also called solutions.
Mass versus Weight
Using Conversion Factors
Chemistry is an experimental science in which a consistent system of measurements is used. Scientists throughout the world use the International System of Units (Système International or SI), which is based on the metric system. However, the metric system in not used on an everyday basis in the United States. It is often necessary to convert between the English system, which is used in the United States, and the SI system. One problem with the SI system is the size of the units sometimes turns out to be inconveniently large or small. Therefore it is often necessary to make conversions within the SI system. For this reason, SI units are modified through the use of prefixes when they refer to either larger or smaller quantities.
Density of a Regular Solid
To count the number of significant figures in a value, use the following rules: 1. Nonzero integers are always significant. For example, 12.34 has four significant figures. 2. Zeros between two nonzero integers are always significant. For example, 1005 has four significant figures. 3. Zeros to the left of the first nonzero digit are not significant. For example, 0.0004 has one significant figure. 4. Zeros before a decimal point and after a nonzero number are significant. For example, 40.1 has three significant figures. 5. Zeros after a nonzero digit are known to be
Mixtures, Solutions, Pure Chemical Substances, Compounds, and Elements
Matter can be classified into several categories.
All substances are either pure chemical substances or mixtures. Mixtures can be separated into their component parts through physical means, whereas pure chemical substances require chemical or nuclear reactions to separate them.
Pure chemical substances can be further divided into elements or compounds.
Mixtures can be either heterogeneous orhomogeneous. Homogeneous mixtures are also called solutions.
Mass versus Weight
Using Conversion Factors
Chemistry is an experimental science in which a consistent system of measurements is used. Scientists throughout the world use the International System of Units (Système International or SI), which is based on the metric system. However, the metric system in not used on an everyday basis in the United States. It is often necessary to convert between the English system, which is used in the United States, and the SI system. One problem with the SI system is the size of the units sometimes turns out to be inconveniently large or small. Therefore it is often necessary to make conversions within the SI system. For this reason, SI units are modified through the use of prefixes when they refer to either larger or smaller quantities.
Density of a Regular Solid
To count the number of significant figures in a value, use the following rules: 1. Nonzero integers are always significant. For example, 12.34 has four significant figures. 2. Zeros between two nonzero integers are always significant. For example, 1005 has four significant figures. 3. Zeros to the left of the first nonzero digit are not significant. For example, 0.0004 has one significant figure. 4. Zeros before a decimal point and after a nonzero number are significant. For example, 40.1 has three significant figures. 5. Zeros after a nonzero digit are known to be