Download presentation

Presentation is loading. Please wait.

Published byBrenda Norton Modified over 5 years ago

1
Percent Composition

2
What is Percent Composition? The percent composition by mass of a compound represents the percent that each element in a compound contributes to the total mass of the compound.

3
How do I calculate percent composition? Formula: %mass = grams of element in 1 mol compound x 100% molar mass of compound Example: What is the percent composition of water (H 2 O)? Step 1: figure out the molar mass from the formula 2 mol Hydrogen x 1.01g = 2.02g 1mol Oxygen x 16.00g = 16.00g molar mass of water = 18.02g Step 2: divide the answer for each atom by the molar mass and multiply by 100 to get a percentage 2.02 g of H / 18.02 g of H 2 O x 100 % = 11.21% Hydrogen 16.00 g of O / 18.02 g of H 2 O x 100 % = 88.79% Oxygen Your percentages should add up to 100%

4
Same concept, but worded differently An 8.20g piece of magnesium combines completely with 5.40g of oxygen to form magnesium oxide. What is the percent composition of the magnesium oxide? Solution: Step 1: Find the mass of the compound 8.20g Mg + 5.40g O = 13.60 g Step 2: Find the percent by mass of each element %Mg = 8.20g x 100% = 60.29% of Mg 13.60 g %O = 5.40g x 100% = 39.71 % of O 13.60 g

5
Your Turn: What is the percent composition of glucose (C 6 H 12 O 6 ) Step 1: figure out the molar mass: Step 2: Divide the answer of each atom by the molar mass and multiply by 100

6
Practice Problems Calculate the percentage composition by mass of the following compounds 1) HgO 2) Na 2 S 3) (NH 4 ) 2 S 4) Sr(NO 3 ) 2

Similar presentations

© 2021 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google