100+ Free CMAS Science Grade 8 Practice Questions

Prepare for the Colorado Measures of Academic Success (CMAS) Science — Grade 8 exam with instant access — no signup required.

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Key Facts: CMAS Science Grade 8 Exam

Grade 8

CMAS Science tested grade (CDE)

ed.cde.state.co.us/assessment/cmas

Free

No student exam fee for standard school administration

CDE Assessment FAQs

Pearson

CDE assessment contractor; TestNav / PearsonAccessnext delivery

Spring 2026 CMAS Overview

Spring

Primary administration window (2026: April 6–24 for CMAS)

CDE Fact Sheets and FAQs

CAS

Aligned to Colorado Academic Standards grade-level expectations

CDE CMAS overview

650–850

Overall scale score range reported on CMAS score reports

CDE interpretive guides

5/8/11

Science tested grades statewide

CDE CMAS overview

SEP

Science and Engineering Practices integrated across large share of points

CMAS Science frameworks

CMAS Science Grade 8 is Colorado's free statewide spring summative (CDE/Pearson), mixed item types on TestNav, performance levels on a 650–850 scale; practice here is English MCQ study only.

Sample CMAS Science Grade 8 Practice Questions

Try these sample questions to test your CMAS Science Grade 8 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is an atom?

A.The smallest particle of an element that still has that element's properties

B.A living cell that can divide on its own

C.A pure energy wave with no mass

D.A mixture of many unrelated compounds

Explanation: An atom is the basic unit of an element that keeps the element's chemical identity. Cells are biological; atoms have mass; mixtures contain more than one substance type.

2Which particle is found in the nucleus and carries a positive charge?

A.Proton

B.Electron

C.Photon

D.Neutron with a negative charge

Explanation: Protons are positively charged particles in the nucleus. Electrons are negative and outside the nucleus; photons are light particles; neutrons are neutral, not negative.

3What mainly distinguishes one pure element from another?

A.The number of protons in each atom's nucleus

B.The sample's color alone with no other properties

C.Whether the sample can be frozen

D.The year the sample was collected

Explanation: Atomic number—the proton count—defines each element. Color, freezing ability, and collection date do not define elemental identity.

4Which example is a molecule?

A.H₂O, two hydrogen atoms bonded to one oxygen atom

B.A single free proton with no electrons nearby

C.A pure sound wave traveling through air

D.Empty space between stars

Explanation: A molecule is two or more atoms bonded together. Water (H₂O) is a molecule. A lone proton is a subatomic particle; sound is a wave; empty space is not matter.

5Students measure the mass of a sealed bag of baking soda and vinegar before and after the reaction. No gas escapes. What should they observe about total mass?

A.Total mass stays the same because mass is conserved in a closed system

B.Total mass must double because a gas formed

C.Total mass becomes zero because the reactants disappear

D.Total mass always decreases when temperature rises

Explanation: In a closed system, atoms rearrange into products but total mass is conserved. Forming gas does not create extra mass if nothing leaves the bag.

6Which change is chemical rather than physical?

A.Wood burning and producing ash, smoke, and new gases

B.Ice melting into liquid water

C.Crushing a rock into smaller pieces

D.Dissolving salt completely in water

Explanation: Burning forms new substances with different chemical properties. Melting, crushing, and dissolving are physical changes that do not produce new chemical identities in the same way.

7A student heats two solid samples. Sample A melts at 80°C and Sample B melts at 180°C. Both look white. What does this best support?

A.The samples may be different substances because melting point is a characteristic property

B.The samples must be identical because both are white

C.Melting points cannot help identify substances

D.Sample A has more protons solely because it melts first

Explanation: Characteristic properties such as melting point help distinguish substances even when appearance is similar. Color alone is weak evidence of identity.

8During a reaction, 12 g of reactant X completely react with 8 g of reactant Y in a sealed flask. What is the total mass of products?

A.20 g

B.12 g

C.8 g

D.4 g

Explanation: Conservation of mass in a closed system means total product mass equals total reactant mass: 12 g + 8 g = 20 g.

9A table shows four substances and whether they react with vinegar (acid): | Substance | Bubbles with vinegar? | | A | Yes | | B | No | | C | Yes | | D | No | Which claim is best supported?

A.A and C likely share a chemical property that B and D lack

B.All four substances are chemically identical

C.B and D must be gases because they do not bubble

D.A and C cannot be solids

Explanation: Bubbling with vinegar is evidence of a chemical interaction with acid. A and C show that property; B and D do not, so the groups differ in at least that chemical behavior.

10What happens to atoms during a chemical reaction?

A.Atoms rearrange into new combinations of molecules or compounds

B.Atoms are permanently destroyed and vanish

C.New atoms are created from pure energy alone

D.All atoms turn into light with no mass left

Explanation: Chemical reactions rearrange atoms into new substances. Atoms are not destroyed or created in ordinary chemical reactions; mass is conserved as atoms recombine.

About the CMAS Science Grade 8 Exam

Colorado Measures of Academic Success (CMAS) Science — Grade 8 is Colorado's grade-level Colorado Measures of Academic Success (CMAS) statewide summative assessment, developed by CDE with Colorado educators and Pearson against the Colorado Academic Standards. It is administered in the spring window (for 2026: April 6–24 per CDE FAQs) on Pearson TestNav. Official forms use mixed item types (selected-response, technology-enhanced, and for many content areas constructed-response tasks). OpenExamPrep free practice is an English-language four-option MCQ study adaptation aligned to CMAS reporting categories and grade-level CAS—not official secure items, not a full TE/CR simulation, and not a substitute for classroom instruction or the official assessment.

Assessment

Question count not published by the exam provider

Time Limit

About 3 hours 15 minutes total across three units for Grade 8 Science (CDE 2025–26 time table; three units per Spring 2026 overview).

Passing Score

CMAS Science and Social Studies overall scale scores range from 650 to 850 and are reported in four performance levels: Partially Met Expectations, Approached Expectations, Met Expectations, and Exceeded Expectations. Met Expectations and Exceeded Expectations indicate grade-level expectations have been met or exceeded (CDE CMAS interpretive guides; social studies cut scores adopted for 2026 reporting after the 2025 CAS-aligned first administration).

Exam Fee

Free for Colorado public school students; CMAS is a state-required summative assessment administered by districts at no cost to families (CDE Assessment FAQs). (Colorado Department of Education (CDE) with assessment contractor Pearson; delivery via PearsonAccessnext / TestNav)

CMAS Science Grade 8 Exam Content Outline

~34% of score points

Physical Science

Matter, chemical reactions, forces/energy concepts in middle school CAS.

~36% of score points

Life Science

Cells, organisms, ecosystems, heredity, and evolution concepts at middle school.

~30% of score points

Earth and Space Science

Earth–sun–moon, Earth’s systems, human impacts, and space systems at middle school.

~65–74% of points involve SEPs (integrated)

Science and Engineering Practices

Practices integrated across clusters, mini-clusters, and standalone items.

How to Pass the CMAS Science Grade 8 Exam

What You Need to Know

Passing score: CMAS Science and Social Studies overall scale scores range from 650 to 850 and are reported in four performance levels: Partially Met Expectations, Approached Expectations, Met Expectations, and Exceeded Expectations. Met Expectations and Exceeded Expectations indicate grade-level expectations have been met or exceeded (CDE CMAS interpretive guides; social studies cut scores adopted for 2026 reporting after the 2025 CAS-aligned first administration).
Assessment: Question count not published by the exam provider
Time limit: About 3 hours 15 minutes total across three units for Grade 8 Science (CDE 2025–26 time table; three units per Spring 2026 overview).
Exam fee: Free for Colorado public school students; CMAS is a state-required summative assessment administered by districts at no cost to families (CDE Assessment FAQs).

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

CMAS Science Grade 8 Study Tips from Top Performers

1Use CDE-sanctioned Colorado Practice Resources (coassessments.com) so students learn TestNav tools and item interactions.

2Align review to grade-level Colorado Academic Standards and CMAS frameworks/evidence statements, not only generic worksheets.

3Review wrong answers by reporting category (for example reading subclaim or math major content) to target instruction.

4Use short, frequent practice sessions across the year rather than cramming only in the April window.

5For constructed-response skills, practice evidence selection, planning, and revision even when using MCQ study items.

Frequently Asked Questions

What is the CMAS Science Grade 8 assessment?

Colorado Measures of Academic Success (CMAS) is Colorado's standards-based statewide summative program. The Grade 8 Science form measures mastery of grade-level Colorado Academic Standards and is developed by CDE with Colorado educators and Pearson.

Is CMAS free for students?

Yes. CMAS is administered through Colorado public schools as a state assessment. Families do not pay an exam fee for standard school-based administration (CDE Assessment FAQs).

How long is the official test?

About 3 hours 15 minutes total across three units for Grade 8 Science (CDE 2025–26 time table; three units per Spring 2026 overview).

What item types appear on the official CMAS?

Official CMAS uses selected-response, technology-enhanced, and often constructed-response or performance/simulation tasks depending on content area. This site offers English four-option MCQ study adaptations only—not an official-format simulation.

How are results reported?

Are these practice questions official CMAS items?

No. These free practice questions are original study aids aligned to Colorado Academic Standards and CMAS frameworks/blueprints. They are not secure official items and do not replace Colorado Practice Resources, classroom instruction, or the official spring assessment.

Who takes CMAS Science?

Students in grades 5, 8, and 11 take grade-level CMAS Science (or CoAlt Science when eligible) at all schools (CDE CMAS overview).

100+ Free CMAS Science Grade 8 Practice Questions

CMAS Science Grade 8

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