Unit 2

Material is used to refer to a specific kind of matter. ,[object Object],Wood Steel Air Milk

A mixture is matter that contains more than one material. ,[object Object],Granite Milk Air

Heterogeneous Materials Mixtures in which the materials are not uniform are called heterogeneous .

Phase ,[object Object],[object Object],Each material in granite is a phase. In ice water, ice & water are different phases.

Interfaces ,[object Object],Ice Water The surfaces of the ice and water are interfaces.

Homogeneous Materials Materials that consist of only one phase are called homogeneous .

Examples Sugar Salt Seawater Air

Solution ,[object Object],[object Object],[object Object],[object Object],[object Object]

Example ,[object Object],Solute? Sugar Solvent? Water

Not all solutions are liquids! Air Made of nitrogen, oxygen, and other gases…

Molarity ,[object Object],[object Object],[object Object],[object Object],[object Object]

Substances Homogeneous materials that always have the same composition.

Substances can be divided into two categories: ,[object Object],[object Object],[object Object],[object Object]

Organic vs. Inorganic ,[object Object],[object Object],[object Object]

Physical and Chemical Changes A quick review…

Physical Changes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Chemical Changes ,[object Object],[object Object],[object Object]

Physical and Chemical Properties A quick review…

Physical Properties ,[object Object],[object Object],[object Object],[object Object],[object Object]

Chemical Properties ,[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Quantitative measurements of energy changes are expressed in joules, J. Calories are used to measure energy changes, too. 1 calorie = 4.184 joules

Energy and Chemical Changes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Activation Energy ,[object Object],[object Object],[object Object]

Measuring Energy Changes ,[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object]

Specific Heat ,[object Object],[object Object],[object Object],[object Object]

Specific Heats (con’t) ,[object Object],[object Object],[object Object]

q = m( Δ T)(C p ) ,[object Object],[object Object],[object Object],[object Object]

Problem ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Step 1 ,[object Object],[object Object],[object Object],[object Object]

Step 2 ,[object Object],[object Object],[object Object],[object Object]

Step 3 ,[object Object],[object Object],[object Object]

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