Changes and Properties

Changes and Properties

Mixtures and Substances

Homogeneous Mixture - well mixed mixture that you can't see the different parts; coffee

Heterogeneous Mixture - unevenly mixed mixture that you can see the different parts; chex mix

Compound - two or more elements chemically bonded together; Salt (NaCl)

Element - simplest building block of matter, found on the periodic table; Oxygen

Multiple Choice

When two or more elements are chemically bonded together, it is called what?

• compound

• mixture

• element

Multiple Choice

Lucky Charms cereal would be an example of what?

• homogeneous mixture

• element

• heterogeneous mixture

Physical vs Chemical

Physical Changes - change in shape, form, or size of a substance, but remains the same substance; tearing paper

Chemical Changes - one substance reacts and becomes a new substance; vinegar and baking soda

Endothermic - reaction that absorbs heat and feels cool

Exothermic - reaction that gives off heat and feels warm

Multiple Choice

When something changes shape, size, or state, but still remains the same substance, it is known as what?

• chemical change

• physical change

Multiple Choice

When a chemical reaction occurs and gives off heat, it is called what kind of reaction?

• exothermic

• endothermic

Counting Atoms

Subscript - little number after the letter that tells you how many atoms of that element there are

Coefficient - big number in front of the symbol that tells you how many of that compound there are (remember to multiply it to each term)

Multiple Choice

How many atoms of Oxygen are in the following: SiO₂

• 1

• 2

• 3

• 4

Multiple Choice

How many atoms of Nitrogen are in the following: 7NH₃

• 7

• 1

• 3

• 21