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Molar Mass and Percent Composition

Molar Mass and Percent Composition

Assessment

Interactive Video

Chemistry

9th - 10th Grade

Practice Problem

Hard

Created by

Emma Peterson

FREE Resource

The video tutorial explains how to calculate the percent composition by mass of elements in water (H2O). It begins with an introduction to the concept and then details the calculation process for hydrogen and oxygen. The molar mass of each element is used, and the results are expressed as percentages. The tutorial concludes with a note on rounding and the importance of accuracy in calculations.

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9 questions

Show all answers

1.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the purpose of finding the percent composition by mass in a compound?

To find the weight of each element in a compound

To calculate the volume of a compound

To measure the density of a compound

To determine the number of atoms in a molecule

2.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the molar mass of hydrogen used in the calculation for H2O?

2.02 grams per mole

1.00 grams per mole

1.01 grams per mole

1.10 grams per mole

3.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

How many hydrogen atoms are present in a molecule of water?

One

Two

Four

Three

4.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the total molar mass of water (H2O)?

16.00 grams per mole

20.00 grams per mole

18.00 grams per mole

18.02 grams per mole

5.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the percent composition by mass of hydrogen in water?

11.11%

10.21%

12.21%

11.21%

6.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the molar mass of oxygen used in the calculation for H2O?

15.99 grams per mole

18.00 grams per mole

17.00 grams per mole

16.00 grams per mole

7.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the percent composition by mass of oxygen in water?

87.84%

88.84%

89.84%

86.84%

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