Science.8.6.E

Previous Next
The student is expected to investigate how mass is conserved in chemical reactions and relate conservation of mass to the rearrangement of atoms using chemical equations, including photosynthesis.
1666 TEKS header image

Knowledge and Skills Statement

Matter and energy. The student understands that matter can be classified according to its properties and matter is conserved in chemical changes that occur within closed systems.

In Grade 6, students learned that chemical reactions may be observed as: a change in thermal energy (increase or decrease in temperature not a result of a change of state), the production of a gas (bubbling), the production of a precipitate (a solid that formed after mixing liquids), or a color change.  

In Grade 8, students will use subscripts and coefficients to determine the number of each type of atom in the products and in the reactants of a balanced chemical equation.  

In high school chemistry, students will balance chemical equations by writing the coefficients for each substance in the reaction so that the equation follows the law of conservation of mass.

a type of change in which a new substance is made from one or more previous substances; occurs during a chemical reaction; a change where the atoms of the original substances are rearranged to make new elements and/or compounds

describes a chemical reaction and includes all of the reactants and all of the products of the reaction

a chemical change that occurs when two or more substances combine to form a new substance; the rearrangement of atoms to produce new compounds

a physical system that does not allow transfer of matter in or out, although energy can flow into and out of the system

in chemical changes, the total mass of the materials does not change (nor does the type and number of atoms); the total mass of the reactants is equal to the total mass of the products

the amount of matter in a substance, measured in grams or kilograms

substance that occupies space, has mass, and is composed of microscopic particles
 

the chemical process by which plants and other photosynthetic organisms produce their own source of energy (food) using energy from sunlight to convert carbon dioxide and water into oxygen and glucose (food)

characteristic of matter that can be used to identify particular materials

Research

Dial, Katrina, Diana Riddley, Kiesha Williams, and Victor Sampson. “Addressing Misconceptions: A Demonstration to Help Students Understand the Law of Conservation of Mass.” The Science Teacher, 76, no. 7 (2009): 54–57. http://www.jstor.org/stable/24144956

Summary: "Addressing Misconceptions: A Demonstration to Help Students Understand the Law of Conservation of Mass" utilizes a predict, observe, and explain instructional strategy to uncover and address student misconceptions.  Many students believe a substance's mass is related to its physical state. This article provides investigation information requiring measurements to confirm the law of conservation of mass.