Unit 5: Physical and Chemical Changes in Matter Study Guide

How can I use only a measuring cylinder and water to find the volume of an irregular object like a rock? Explain this process

Read and record the amount of water. I will drop the rock in the water. Read and record the amount of rock and water, then subtract the amount of water.

Using this definition explain why some objects are floating and some objects fall down. (Textbook 163 pages)

Mass per unit volume. If the object is denser than the fluid in it, it will sink. When the density is small, it floats

Explain how a substance becomes a characteristic of a new kind of substance. You can observe them only during chemical changes

Particles move fastest in the gas. They move slowest on solids. Gas is the most expensive, solid is the least heat

Mixtures and solutions are made of materials physically present but not chemically bonded. In solution, individual particles are not visible because they dissolve in the material.

In a chemical change, the particles of the substance divide and form new substances with different properties.

According to the evidence, energy is used or abandoned, the nature of the new substance is different from the original substance, the change does not easily recover easily

With physical change, there are material changes, but no new change will occur. In chemical change, new substances with different properties are formed

There are two types of material change: physical change and chemical change. As its name implies, physical changes affect the physical properties of substances and chemical changes affect the chemical nature of the substance. Many physical changes are reversible (such as heating and cooling), but chemical changes are usually irreversible, or can be reversed only by additional chemical changes. Another way of thinking is that substances are not fundamentally different substances due to physical changes, but substances may become chemically new substances due to chemical changes. For example, there are two physical changes in a mixed smoothie. To change the shape of each fruit and to mix various fruits. Since the smoothie component during the mixing process in chemistry has not changed (eg, water, vitamin water and no change), we know that no chemical change will occur

Observation and research problems often change, and these changes may be physical or chemical. A physical change is a change in the shape of a substance that does not change its chemical composition. The chemical formula of the substance did not change before and after the change. A chemical change or chemical reaction is a change that occurs when atoms of a material are repositioned and bonds between atoms are broken or formed. The structure or composition of the material changes during the chemical reaction

The change between the states of the substance can be a physical change or a chemical change. In physical change, even though the physical properties change, the chemical formula of the substance remains the same. Physical properties include taste, aroma, texture, color and so on. Normally, body changes can be restored. Ice can dissolve in liquids, it can be refrozen to solid state. In each state, the chemical formula of water, H2O has not been changed. Another example of a physical change is the use of a paint, crayon or marker for filtering, cutting, melting and coloring the surface of something. Examples of physical changes are shown in Figure 2 and Figure 3. 6 A and B