Search Header Logo

Empirical & Molecular Formula

Authored by Patricia Dimapilis

Chemistry

10th - 12th Grade

NGSS covered

Used 1K+ times

Empirical & Molecular Formula
AI

AI Actions

Add similar questions

Adjust reading levels

Convert to real-world scenario

Translate activity

More...

About

This quiz focuses on empirical and molecular formulas, a fundamental topic in stoichiometry and chemical composition analysis appropriate for grades 10-12 chemistry. Students must demonstrate mastery of several interconnected concepts: converting percent composition data to empirical formulas using molar masses and mole ratios, calculating molecular formulas from empirical formulas when given molecular mass, determining percent composition from molecular formulas, and distinguishing between empirical and molecular representations of compounds. The problems require students to perform multi-step calculations involving atomic masses, mole conversions, ratio simplification, and multiplicative relationships between empirical and molecular formulas. Students need solid computational skills, understanding of significant figures, and the ability to recognize when empirical and molecular formulas are identical versus when they differ by whole-number multiples. Created by Patricia Dimapilis, a Chemistry teacher in the US who teaches grades 10 and 12. This quiz serves as an excellent tool for formative assessment or guided practice as students build proficiency with formula determination problems. Teachers can use these questions as warm-up problems to activate prior knowledge about molar mass calculations, assign them as homework to reinforce classroom instruction, or implement them during review sessions before unit tests. The variety of question types—from computational problems requiring percent composition analysis to conceptual questions about the relationship between empirical and molecular formulas—allows instructors to gauge both procedural fluency and conceptual understanding. This assessment aligns with NGSS HS-PS1-7 (using mathematical representations to support the claim that atoms are conserved during chemical reactions) and supports Common Core mathematical practices in chemistry contexts.

    Content View

    Student View

12 questions

Show all answers

1.

MULTIPLE CHOICE QUESTION

15 mins • 12 pts

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

C2H3O2
CH2O
C2H4O2
C3H8O3

2.

MULTIPLE CHOICE QUESTION

15 mins • 12 pts

What is the empirical formula for the following molecular formula: C6H14

C6H14
C3H7
CH2
CH3

3.

MULTIPLE CHOICE QUESTION

1 min • 12 pts

What is the molecular formula if the empirical formula is C2H5 and the molecular molar mass is 58.14 g/mol?

C2H5
C4H10
C1H2.5
C4H8

4.

MULTIPLE CHOICE QUESTION

15 mins • 12 pts

What is the empirical formula for the following molecular formula: C5H12

C5H12
CH3
CH2
C2.5H6

5.

MULTIPLE CHOICE QUESTION

1 min • 12 pts

Find the percent composition of N2S2.

N: 69.6%  S: 30.4%
N:36% S: 75.6%
N: 96.6% S: 3.4%
N: 30.4% S: 69.6%

Tags

NGSS.HS-PS1-7

6.

MULTIPLE CHOICE QUESTION

15 mins • 12 pts

What is the molecular formula for a compound with the empirical formula: K2SOand a molecular mass of 696g.

K2SO
K8SO16
K8S4O
K8S4O16 

7.

MULTIPLE CHOICE QUESTION

15 mins • 12 pts

What is the molecular formula for a compound with the empirical formula: CaCl2  and a molecular mass of 330g.

Ca2Cl4
Ca3Cl6
Ca3Cl9
Ca3Cl5

Tags

NGSS.HS-PS1-7

Access all questions and much more by creating a free account

Create resources

Host any resource

Get auto-graded reports

Google

Continue with Google

Email

Continue with Email

Classlink

Continue with Classlink

Clever

Continue with Clever

or continue with

Microsoft

Microsoft

Apple

Apple

Others

Others

Already have an account?