Characteristics of Chemical Reactions

precipitate

A solid that is deposited from a solution

product

A substance produced during a chemical reaction.

reactant

A substance that takes part in and undergoes change during a reaction

chemical reaction

The process by which one or more substances change to produce one or more new substances with different properties

Rust forming on a piece of iron is an example of a chemical change because a new substance was formed. the evidence is

a color change

Rust forming on a piece of iron is an example of a chemical change because?

a new substance was formed (oxygen bonded with iron)

What is a chemical reaction?

a process where the bonds between atoms are broken and a new arrangement of bonds between atoms is formed.

An unexpected change in _____________ is a sign that a chemical reaction may have occurred.

color

In a chemical process, atoms that make up a substance are regrouped into different ______________ to form new substances with different _______________.

molecules, properties

A _________________ increase or decrease and the production of light are both signs that a chemical reaction occurred.

temperature

Substances giving off a smell, or ____________, while being combined is also an indicator of a chemical reaction.

gas

molecule

The simplest unit of a chemical compound that can exist; formed when two or more atoms chemically combine

atom

The smallest particle of an element; made of electrons, protons, and neutrons

A chemical reaction occurs that involves combining the following reactants: 4 atoms of oxygen, 6 atoms of carbon, and 2 atoms of hydrogen. How many atoms of each element will there be in the product?

There will still be 4 atoms of oxygen, 6 atoms of carbon, and 2 atoms of hydrogen in the product, however they will be rearranged into different molecules.

Identify the five signs of a chemical change.

Unexpected color change Increase or decrease in temperature Precipitate forms Production of light Formation of a gas (bubbles or odor)

How can you tell when a chemical reaction has occurred?

When a new substance has been formed. The signs are production of a gas, light, sound, or color change. A change of temperature (either increase or decrease) is another way to indicate that a chemical reaction occurred.

Which of the following is a chemical change: cutting paper, melting snow, burning logs, carving wood, and/or baking cake?

burning logs and baking a cake

Rust forming on a piece of iron is an example of a

chemical change

A _______________ is a solid substance that forms and separates from a solution and may indicate that a chemical reaction has occurred.

precipitate

In a chemical reaction, when you combine two or more substances called _______, the atoms interact, rearrange, and produce new substances called ________.

reactants, products