Unit A: 1.3Matter combines to form different

substances•How pure matter and mixed matter are

different•How atoms and elements are related

•How atoms form compounds

• Mix 1 teaspoon of each water and cornstarch. Observe.

• Can you still see each substance? How different?

• Oobleck is formed! NEW substance

Matter: Pure or Mixed

• Even drinking water is not pure: minerals dissolved in and chemicals added to it

• Pure: if a substance contains only a single type of atom (such as gold) OR a single combination of atoms bonded together (such as water)

Element

• Contains only a single type of atom – cannot be separated into other substances

• Ex: silver, oxygen, hydrogen, helium, etc

• Diamond and graphite are both made of Carbon. The individual atoms have the same properties, but are in different arrangement giving the substance very different properties

Compounds• Two or more different types of atoms bonded together• Water, carbon dioxide, table salt• Individual elements can have very different properties

compared to the compound they form

• Break down a compound into smallest parts that are still that substance, individual atoms or elements?

• No!• Break down a pure element into smallest parts that are still

that substance, atoms of that element?• Yes! • If you break a compound into the parts that compose it?• Atoms of the elements that compose it (ex: NaCl)

Mixtures

• Mix of different substances• Sea water: contains water, salt, other minerals• Blood: cells and plasma

– Plasma: water, sugar, fat, protein, salts, minerals• Combo of different substance that remain their

individual substances and can be separated physically.

• Will not always contain the same amount of the various substances– Think fruit salad!

Compounds vs Mixtures

Mixtures Compounds

substances remain the same new substance formed, atoms bond together

can be separated by physical means

separated by breaking the bonds between atoms

Proportion of diff. substances can vary

-depends on where you sample (unless Homogeneous)

Proportions of diff. substance are fixed

-any sample yields same type and number of atoms