CHEM.9.A

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The student is expected to interpret, write, and balance chemical equations, including synthesis, decomposition, single replacement, double replacement, and combustion reaction using the law of conservation of mass;
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Knowledge and Skills Statement

Science concepts. The student understands how matter is accounted for in chemical reaction.

Students can sometimes make simple mistakes while using the coefficients and subscripts to calculate the quantity of each element in a molecule. The coefficients in the balanced chemical reaction indicate how many moles (or particles) of each substance are used or produced when the reaction proceeds to completion. The coefficient is multiplied by the subscript to determine the quantity of each element.

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 chemical reaction between substances that includes oxygen as a reactant and water as a product; usually accompanied by the generation of heat and light in the form of flame

a chemical reaction in which one reactant breaks down into two or more products

 occurs when parts of two ionic compounds are exchanged, making two new compounds; also called a double displacement reaction

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

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

a chemical reaction in which one element takes the place of another element in a compound; also called a substitution reaction

a type of reaction in which multiple reactants combine to form a single product; also called an addition reaction

Research

Vander Klok, Don. "Balancing Chemical Equations, Using Linear Equations." Gazette - Ontario Association for Mathematics 56, no. 4 (2018): 30-32. https://www.proquest.com/scholarly-journals/balancing-chemical-equations-using-linear/docview/2057942121/se-2

Summary:  The challenge of balancing an equation is to find the values for the coefficients. Trial and error (hopefully combined with "educated guessing") is the most common way students determine the coefficients. A better approach uses a system of linear equations. The parts of the equations are the coefficients and the number of atoms of each element.

Research

Bílek, Martin, Małgorzata Nodzyńska, Wioleta Kopek-Putała, and Paulina Zimak-Piekarczyk."Balancing Chemical Equations Using Sandwich Making Computer Simulation Games As A Supporting Teaching Method." Problems of Education in the 21st Century 76, no. 6 (2018): 779-799. https://doi.org/10.33225/pec/18.76.779

Summary:  Writing and balancing equations of chemical reactions is one of the most difficult elements of chemistry education for students. The aim of this research was to examine whether using computer simulations can help younger children to balance chemical equations before they start to learn chemistry by using the psychological theory of transfer. It was decided first to teach children how to “make sandwiches” using a computer simulation game.