Matter

Question 1

Define: Pure Substance

Answer 1

A substance whose properties are the same throughout

Question 2

Define: Mixture

Answer 2

A combination of two or more pure substances

Question 3

Define: Homogeneous Mixture

Answer 3

A mixture whose composition is the same throughout the sample

Question 4

Define: Heterogeneous Mixture

Answer 4

Mixture whose composition is different in different parts of the sample

Question 5

Define: Law of Mass Conservation

Answer 5

In any chemical or physical process, the total mass of everything involved must remain the same.

Note: keep in mind that this does not apply to ALL physical processes. In some special cases, matter is destroyed (ex: nuclear fission).

Question 6

Define: Element

Answer 6

A substance that cannot be chemically broken down into similar substances

Question 7

Define: Compound

Answer 7

A pure substance that is composed of two or more elements

Question 8

Define: Law of Definite Proportions

Answer 8

A given compound will always have the same proportion of elements by mass

Question 9

Define: Molecule

Answer 9

A combination of two or more atoms joined together

Question 10

Define: Law of Multiple Proportions

Answer 10

When two elements combine to form different compounds, a fixed amount of one element will combine with the other element so that the ratio of the masses of the other element is a small whole number.

In plain words: When you have two compounds formed by the same to elements, you can take the ratio of the elements from both compounds. Then, use those two answers and turn THEM into a ratio. The Law of Multiple Proportions is saying that the answer to that ratio will be a small whole number.

Also, in that ginormous sentence, it also said you have to have a fixed amount of one of the elements to figure out the ratio, in order to have a starting point.

Question 11

Define: Isotopes

Answer 11

Two or more atoms of the same element that have different numbers of nuetrons.

Ex: isotopes of carbon

Question 12

Dalton’s Atomic Theory, revised

Answer 12

1. All matter is made up of atoms.
2. All atoms of a given element are identical in their chemical properties.
3. Compounds are formed by a combination of two or more different kinds of atoms.
4. A chemical reaction is a rearrangement of the atoms that exist in the substances which are reacting.