Physical and Chemical Change

Opening Assignment 1. What page does Chapter 6 Section 1 start on? 2. What are the key concepts? Write down both of them. 3. Look at the pictures on page 186…. What types of change occurs in the marshmallow? 4. What is the difference between the two types of changes in matter.

What have we learned about Matter is anything that has mass and takes up space. To describe matter we refer to its physical and chemical properties Chemistry is mostly about changes in matter There are two changes that can occur in matter. Physical and Chemical changes

Physical Change What is it? Physical Change is when the appearance of matter changes but not its composition. (it is the same substance but it looks different!)

Physical Change What does a physical change look like? When a substance changes state (solid liquid or gas) or form ………..dissolving sugar

Physical Change What does a physical change look like? 2. When a substance changes shape …………….crushing Other ways a substance can change shape ……breaking, chopping, tearing…..

Chemical Change Chemical change occurs when a new substance is made. Chemical change = chemical reaction The new substance has properties that are different than the original substances. Chemical Change What is it?

Chemical Changes are everywhere!

Worksheet – Identifying Physical and Chemical changes

Brainstorm – What are the signs that a chemical change (reaction) occurred?

Opening Assignment Copy the chemical equation below Label the reactant(s) and the product(s) What does the arrow mean? CaCO3  CaO + CO2

Signs of a chemical change What does a chemical change look like? changes in color release or gain of energy (frequently in the form of heat) Becomes either cold or hot change in odor or taste

Other signs of a chemical change formation of a gas (bubbles appear) formation of a solid precipitate

Opening Assignment – page 54 1. What is energy? 2. Find the sentence and fill in the blanks…. Every chemical or physical change includes a _____________________________________

Matter and Thermal Energy Every chemical or physical change includes a change in energy.

Exothermic and Endothermic Reactions Exothermic -- a change in which energy is released – its feels hotter Warming your hands by the fire  Endothermic – a change in which energy is absorbed – it feels colder Ice pack