Download presentation

Presentation is loading. Please wait.

Published byKaleigh Corbridge Modified over 2 years ago

1
How to Count Atoms Using subscripts and Coefficients to count the number of atoms in molecules.

2
Coefficient The LARGE number written in front tells you how many molecules you have. A single molecule of water is written: H2O Example: 10 water molecules would be written as 10H 2 O = 20 hydrogen atoms (2 x 10) & 10 oxygen atoms (10 x 1)

3
Subscript If an element has a small number after it, this is how many atoms of that specific atom there are. Example H 2 O –TWO Hydrogen atoms, and ONE Oxygen atom C 2 H 4 –TWO Carbon atoms and FOUR Hydrogen atoms

4
IF AN ATOM DOES NOT HAVE A NUMBER IN FRONT OR BEHIND, IT IS ALWAYS ONE

5
Putting the Two Together If you have coefficients AND subscripts, you need to multiply the coefficient by the subscript. Examples: 2 MnO 4 (2 x 1 =) TWO Mn manganese atoms and (2 x 4 = ) EIGHT O oxygen atoms 3 HPO 4 : (3 x 1 = ) THREE H hydrogen atoms, (3 x 1 = ) THREE P phosphorous atoms, and ( 3 x 4 = ) TWELVE O oxygen atoms

6
Brackets If there are brackets within your molecule... A) The coefficient applies to ALL atoms in the molecule, bracket or not. B) A subscript OUTSIDE the bracket applies to ALL atoms INSIDE the bracket

7
EXAMPLES Al(NO 3 ) 3 has ONE Al Aluminum atom, THREE N Nitrogen atoms, and NINE (3 x 3) O oxygen atoms 3 Au 2 (SeO 4 ) 3 has SIX Au gold atoms (2 x 3), NINE Se selenium atoms (3 x 3), and THIRTY-SIX O oxygen atoms (4 x 3 x 3).

Similar presentations

OK

We have been studying about elements just by themselves such as oxygen and hydrogen. If you put them together you have a molecule of water (H 2 O). A.

We have been studying about elements just by themselves such as oxygen and hydrogen. If you put them together you have a molecule of water (H 2 O). A.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on birds and animals Free ppt on self development Ppt on forests in india Ppt on c language fundamentals inc Download ppt on live line maintenance Ppt on employee engagement strategy Ppt on data collection methods pdf Ppt on media advertising Ppt on chapter 12 electricity Ppt on index numbers meaning