Answer:
Step-by-step explanation:
Distinguish between physical and chemical changes. Include examples in your explanations.
Physical changes are changes in the physical properties of a substance that do not alter its chemical composition. For example, changes in state such as melting, boiling, freezing, and condensation are all physical changes. Other examples of physical changes include changes in shape, size, and color.
Chemical changes, on the other hand, result in a new substance with different properties than the original substance. This is due to a change in the chemical composition of the substance. Examples of chemical changes include burning, rusting, fermentation, and decomposition.
What are the differences among elements, compounds, and mixtures?
An element is a substance that cannot be broken down into simpler substances by chemical means. It is made up of only one type of atom. Examples of elements include gold, carbon, and oxygen.
A compound is a substance that is made up of two or more different elements chemically combined in a fixed ratio. The properties of a compound are different from the properties of the elements that make it up. Examples of compounds include water (H2O), carbon dioxide (CO2), and table salt (NaCl).
A mixture is a combination of two or more substances that are not chemically combined. Mixtures can be homogeneous (uniform in composition) or heterogeneous (non-uniform in composition). Examples of mixtures include air (a mixture of gases), saltwater (a mixture of salt and water), and soil (a mixture of minerals, organic matter, and water).
Fill in the chart below to identify the properties of shape and volume for each type of matter.
Shape Volume
Solid Definite Definite
Liquid Indefinite Definite
Gas Indefinite Indefinite
Explain how atomic mass and molecular mass are determined.
Atomic mass is determined by adding the number of protons and neutrons in the nucleus of an atom. Since protons and neutrons have almost the same mass, the atomic mass of an element is approximately equal to the number of protons and neutrons.
Molecular mass is determined by adding the atomic masses of the atoms that make up a molecule. For example, the molecular mass of water (H2O) is determined by adding the atomic masses of two hydrogen atoms and one oxygen atom.
Fill in the chart below to identify and describe the parts of an atom.
Location Charge
Proton Nucleus Positive
Neutron Nucleus Neutral
Electron Outside the nucleus Negative
Identify the assumptions made as part of Dalton’s atomic theory.
Dalton's atomic theory, which was proposed in the early 19th century, made the following assumptions:
All matter is made up of tiny particles called atoms.
Atoms are indivisible and cannot be created or destroyed.
Atoms of the same element are identical in mass and properties.
Chemical reactions occur when atoms are rearranged, separated, or combined.
Compounds are formed when atoms of different elements combine in fixed ratios.