Law of Conservation of Mass

Grade 7 Science Worksheets

The Law of Conservation of Mass states that the total mass in a closed system remains constant.

Table of Contents:

Law of Conservation of Mass
Formula for Law of Conservation of Mass
FAQs

eTutorWorld Online Tutoring

Law of Conservation of Mass - Grade 7 Science Worksheet PDF

This is a free printable / downloadable PDF worksheet with practice problems and answers. You can also work on it online.

10+ Questions

Untimed

10+ Marks

Free

Printable

Downloadable

Solve Worksheet

"We really love eTutorWorld!"

"We really love etutorworld!. Anand S and Pooja are excellent math teachers and are quick to respond with requests to tutor on any math topic!" - Kieran Y (via TrustSpot.io)

View 7th Grade Online Tutoring Services

"My daughter gets distracted easily"

"My daughter gets distracted very easily and Ms. Medini and other teachers were patient with her and redirected her back to the courses.

With the help of Etutorworld, my daughter has been now selected in the Gifted and Talented Program for the school district"

- Nivea Sharma (via TrustSpot.io)

Book a Free Class

Law of Conservation of Mass

The law of conservation of mass means that the mass of the products of a chemical reaction or physical process will always be equal to the mass of the reactants.

For example, if you burn a piece of wood, the mass of the ash, smoke, and gases produced will be equal to the mass of the wood that was burned. Even though the wood is destroyed, the mass is still there, just in a different form.

Another example is when a mixture of hydrogen and oxygen gases are combined to make water, the mass of the water formed will be equal to the total mass of the hydrogen and oxygen gases.

In simple terms, the law of conservation of mass states that the total amount of mass in a closed system remains constant and it can be converted from one form to another but cannot be created or destroyed.

“There have been times when we booked them last minute, but the teachers have been extremely well-prepared and the help desk at etutorworld is very prompt.

Our kid is doing much better with a higher score.”

- Meg, Parent (via TrustSpot.io)

7th Grade Tutoring

eTutorWorld offers Personalized Online Tutoring for Math, Science, English, and Standardised Tests.

Our Tutoring Packs start at just under $21 per hour, and come with a moneyback guarantee.

Schedule a FREE Trial Session, and experience quality tutoring for yourself. (No credit card required.)

Book a Free Class

Formula for Law of Conservation of Mass

The formula for the law of conservation of mass is:

mass of reactants = mass of products

This formula can be expressed mathematically as:

m_reactants = m_products

Where m represents the mass of the reactants or products.

For example, if you have 100 grams of hydrogen gas (H2) and 200 grams of oxygen gas (O2) that react to form water (H2O), the mass of the reactants and products can be calculated as follows:

mass of reactants (H2 + O2) = 100 grams + 200 grams = 300 grams
mass of products (H2O) = 300 grams

As you can see, the mass of the reactants (hydrogen and oxygen gas) is equal to the mass of the product (water), which confirms that the law of conservation of mass holds true.

Another example, if you have 20 grams of magnesium metal (Mg) and 40 grams of oxygen gas (O2) that react to form magnesium oxide (MgO), we can calculate the mass of the reactants and products as follows:

mass of reactants (Mg + O2) = 20 grams + 40 grams = 60 grams
mass of products (MgO) = 60 grams

As you can see, the mass of the reactants (magnesium metal and oxygen gas) is equal to the mass of the product (magnesium oxide), which confirms that the law of conservation of mass holds true.

Do You Stack Up Against the Best?

If you have 30 minutes, try our free diagnostics test and assess your skills.

Free Diagnostic Test for 7th Grade

Law of Conservation of Mass FAQS

What is the law of conservation of mass?

The law of conservation of mass states that the total mass in a closed system remains constant, meaning that the mass of the products of a chemical reaction or physical process will always be equal to the mass of the reactants.

How is the law of conservation of mass related to the law of conservation of energy?

The law of conservation of mass is related to the law of conservation of energy in that both principles state that certain quantities (mass and energy, respectively) cannot be created or destroyed, only transferred or converted from one form to another.

Can mass be lost in a system?

Mass cannot be lost in a closed system, but it can be converted from one form to another. For example, in a chemical reaction, the mass of the reactants will be equal to the mass of the products.

What are some examples of mass conservation in everyday life?

Examples of mass conservation in everyday life include baking a cake (the mass of the ingredients is equal to the mass of the final product), burning wood in a fireplace (the mass of the wood is equal to the mass of the ash and gases produced), and the burning of fossil fuels (the mass of the fuel is equal to the mass of the ash and gases produced).

How does the law of conservation of mass apply to living things?

The law of conservation of mass applies to living things in the sense that the mass they consume must come from somewhere. For example, plants take in carbon dioxide and water, which they use to make carbohydrates and oxygen through photosynthesis. The mass of the carbohydrates and oxygen is equal to the mass of the carbon dioxide and water consumed.

Kathleen Currence is one of the founders of eTutorWorld. Previously a middle school principal in Kansas City School District, she has an MA in Education from the University of Dayton, Ohio. She is a prolific writer, and likes to explain Science topics in student-friendly language. LinkedIn Profile

Affordable Tutoring Now Starts at Just $21

eTutorWorld offers affordable one-on-one live tutoring over the web for Grades K-12. We are also a leading provider of Test Prep help for Standardized Tests (SCAT, CogAT, MAP, SSAT, SAT, ACT, ISEE, and AP).

What makes eTutorWorld stand apart are: flexibility in lesson scheduling, quality of hand-picked tutors, assignment of tutors based on academic counseling and diagnostic tests of each student, and our 100% money-back guarantee.

Whether you have never tried personalized online tutoring before or are looking for better tutors and flexibility at an affordable price point, schedule a FREE TRIAL Session with us today.

*There is no purchase obligation or credit card requirement

Book a Free Class