{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CHEM151Chapter 2

Chemistry (MasteringChemistry Series)

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
9/5/2008 1 Chapter 2 Atoms, Molecules, Photo courtesy National Institute of Standards and Technology (NIST) STM image (7 nm x 7 nm) of a single zigzag chain of cesium atoms (red) on a gallium-arsenside surface (blue) and Ions on a gallium arsenside surface (blue) Nickel atoms – STM http://www.almaden.ibm.com/vis/stm/atomo.html Conservation of Mass Law of Conservation of Mass: mass is neither created nor destroyed in a chemical reaction. (Cannot create nor destroy matter) Experiment: 1774 - Priestley isolated oxygen by heating HgO (mercury(II) oxide). When carried out in a closed container the mass didn’t change. Law of Definite Proportions Lavoisier discovered that all samples of a single substance exist in the same ratio by mass ratio by mass. – H 2 O: 1 part H, 8 parts O, by mass – CO 2 : 1 part C, 2.7 parts O, by mass Elements combine in specific proportions.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
9/5/2008 2 Dalton's Theory: n All matter is composed of atoms - indivisible particles that are exceedingly small. o Atoms of an element are identical to one another Mass and other properties (physical & chemical) Dalton’s Atomic Theory - Mass and other properties (physical & chemical) - However, they are different from atoms of other elements. p Atoms are not created nor destroyed in chemical reactions. - Reactions only change how atoms are arranged. q Atoms combine in small, whole-number ratios to form compounds. - Definite composition 4 Law of Multiple Proportions One consequence of Dalton’s theories Elements can combine in different ways to form different compounds, but the mass ratios of the different substances are small,
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}