Atoms Rearranged in Reactions - Middle School Physical Science
Card 1 of 25
What is a product in a chemical reaction model?
What is a product in a chemical reaction model?
Tap to reveal answer
A new substance formed by rearranging atoms. Products appear on the right side of the equation.
A new substance formed by rearranging atoms. Products appear on the right side of the equation.
← Didn't Know|Knew It →
Identify the number of H atoms in $2H_2 + O_2 \rightarrow 2H_2O$ on the reactant side.
Identify the number of H atoms in $2H_2 + O_2 \rightarrow 2H_2O$ on the reactant side.
Tap to reveal answer
4 H atoms. $2H_2$ means 2 molecules × 2 atoms each.
4 H atoms. $2H_2$ means 2 molecules × 2 atoms each.
← Didn't Know|Knew It →
Identify the number of O atoms in $2H_2 + O_2 \rightarrow 2H_2O$ on the product side.
Identify the number of O atoms in $2H_2 + O_2 \rightarrow 2H_2O$ on the product side.
Tap to reveal answer
2 O atoms. $2H_2O$ means 2 molecules × 1 O atom each.
2 O atoms. $2H_2O$ means 2 molecules × 1 O atom each.
← Didn't Know|Knew It →
Identify the coefficient needed to balance oxygen: $2H_2 + O_2 \rightarrow \square H_2O$.
Identify the coefficient needed to balance oxygen: $2H_2 + O_2 \rightarrow \square H_2O$.
Tap to reveal answer
- 2 water molecules contain 2 O atoms total.
- 2 water molecules contain 2 O atoms total.
← Didn't Know|Knew It →
Identify the total number of O atoms in $3CO_2$.
Identify the total number of O atoms in $3CO_2$.
Tap to reveal answer
6 O atoms. 3 molecules × 2 O atoms per molecule.
6 O atoms. 3 molecules × 2 O atoms per molecule.
← Didn't Know|Knew It →
Which side has more C atoms in $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$?
Which side has more C atoms in $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$?
Tap to reveal answer
Neither side; both have 1 C atom. $CH_4$ has 1 C; $CO_2$ has 1 C.
Neither side; both have 1 C atom. $CH_4$ has 1 C; $CO_2$ has 1 C.
← Didn't Know|Knew It →
What changes during a chemical reaction: the types of atoms or their arrangement?
What changes during a chemical reaction: the types of atoms or their arrangement?
Tap to reveal answer
Only the arrangement changes; the types of atoms stay the same. Atoms form new bonds but remain the same elements.
Only the arrangement changes; the types of atoms stay the same. Atoms form new bonds but remain the same elements.
← Didn't Know|Knew It →
What is the main purpose of balancing a chemical equation?
What is the main purpose of balancing a chemical equation?
Tap to reveal answer
To show equal numbers of each atom on both sides. This follows the law of conservation of mass.
To show equal numbers of each atom on both sides. This follows the law of conservation of mass.
← Didn't Know|Knew It →
Which parts of a chemical equation can you change to balance it: subscripts or coefficients?
Which parts of a chemical equation can you change to balance it: subscripts or coefficients?
Tap to reveal answer
Coefficients only; subscripts must not be changed. Changing subscripts would create different compounds.
Coefficients only; subscripts must not be changed. Changing subscripts would create different compounds.
← Didn't Know|Knew It →
What do subscripts represent in a chemical formula such as $H_2O$?
What do subscripts represent in a chemical formula such as $H_2O$?
Tap to reveal answer
The number of each type of atom in one molecule. Subscripts show atomic composition of compounds.
The number of each type of atom in one molecule. Subscripts show atomic composition of compounds.
← Didn't Know|Knew It →
What do coefficients represent in a particle model of a reaction?
What do coefficients represent in a particle model of a reaction?
Tap to reveal answer
The number of molecules (or formula units) present. Coefficients multiply the entire formula.
The number of molecules (or formula units) present. Coefficients multiply the entire formula.
← Didn't Know|Knew It →
What does the law of conservation of mass state for a chemical reaction?
What does the law of conservation of mass state for a chemical reaction?
Tap to reveal answer
Mass is conserved; reactant mass equals product mass. Matter cannot be created or destroyed in chemical reactions.
Mass is conserved; reactant mass equals product mass. Matter cannot be created or destroyed in chemical reactions.
← Didn't Know|Knew It →
What is conserved in a chemical reaction: atoms, mass, or both?
What is conserved in a chemical reaction: atoms, mass, or both?
Tap to reveal answer
Both atoms and total mass are conserved. The law of conservation applies to both matter and individual atoms.
Both atoms and total mass are conserved. The law of conservation applies to both matter and individual atoms.
← Didn't Know|Knew It →
Which option is balanced: A) $H_2 + O_2 \rightarrow H_2O$ or B) $2H_2 + O_2 \rightarrow 2H_2O$?
Which option is balanced: A) $H_2 + O_2 \rightarrow H_2O$ or B) $2H_2 + O_2 \rightarrow 2H_2O$?
Tap to reveal answer
B) $2H_2 + O_2 \rightarrow 2H_2O$. Option A has unequal O atoms (2 vs 1).
B) $2H_2 + O_2 \rightarrow 2H_2O$. Option A has unequal O atoms (2 vs 1).
← Didn't Know|Knew It →
Identify what a balanced equation demonstrates about atoms in reactants and products.
Identify what a balanced equation demonstrates about atoms in reactants and products.
Tap to reveal answer
Each element has the same atom count on both sides. This satisfies conservation of mass.
Each element has the same atom count on both sides. This satisfies conservation of mass.
← Didn't Know|Knew It →
What is a reactant in a chemical reaction model?
What is a reactant in a chemical reaction model?
Tap to reveal answer
A starting substance that is changed during the reaction. Reactants appear on the left side of the equation.
A starting substance that is changed during the reaction. Reactants appear on the left side of the equation.
← Didn't Know|Knew It →
What does the law of conservation of mass state for a chemical reaction?
What does the law of conservation of mass state for a chemical reaction?
Tap to reveal answer
Total mass of reactants equals total mass of products. Matter cannot be created or destroyed in chemical reactions.
Total mass of reactants equals total mass of products. Matter cannot be created or destroyed in chemical reactions.
← Didn't Know|Knew It →
What does it mean to say atoms are conserved in a chemical reaction?
What does it mean to say atoms are conserved in a chemical reaction?
Tap to reveal answer
Atoms are rearranged; none are created or destroyed. Bonds break and reform, but the same atoms remain.
Atoms are rearranged; none are created or destroyed. Bonds break and reform, but the same atoms remain.
← Didn't Know|Knew It →
What do coefficients represent in a chemical equation model?
What do coefficients represent in a chemical equation model?
Tap to reveal answer
The number of molecules or formula units present. Shows how many of each molecule participate in the reaction.
The number of molecules or formula units present. Shows how many of each molecule participate in the reaction.
← Didn't Know|Knew It →
Which option best describes atoms in a closed-system chemical reaction model?
Which option best describes atoms in a closed-system chemical reaction model?
Tap to reveal answer
All atoms remain in the system and are rearranged. No atoms enter or leave; they only reorganize.
All atoms remain in the system and are rearranged. No atoms enter or leave; they only reorganize.
← Didn't Know|Knew It →
What do subscripts represent in a chemical formula model?
What do subscripts represent in a chemical formula model?
Tap to reveal answer
The number of each type of atom in one molecule. Small numbers indicate atom count within a single molecule.
The number of each type of atom in one molecule. Small numbers indicate atom count within a single molecule.
← Didn't Know|Knew It →
Which part of a chemical equation lists the reactants?
Which part of a chemical equation lists the reactants?
Tap to reveal answer
The left side of the arrow. Starting materials appear before the reaction arrow.
The left side of the arrow. Starting materials appear before the reaction arrow.
← Didn't Know|Knew It →
Which part of a chemical equation lists the products?
Which part of a chemical equation lists the products?
Tap to reveal answer
The right side of the arrow. New substances formed appear after the reaction arrow.
The right side of the arrow. New substances formed appear after the reaction arrow.
← Didn't Know|Knew It →
What is the main goal when balancing a chemical equation model?
What is the main goal when balancing a chemical equation model?
Tap to reveal answer
Equal atom counts for each element on both sides. Conservation of mass requires equal atoms before and after.
Equal atom counts for each element on both sides. Conservation of mass requires equal atoms before and after.
← Didn't Know|Knew It →
What is the only change you are allowed to make to balance an equation?
What is the only change you are allowed to make to balance an equation?
Tap to reveal answer
Change coefficients, not subscripts in formulas. Subscripts define the compound; only coefficients can adjust.
Change coefficients, not subscripts in formulas. Subscripts define the compound; only coefficients can adjust.
← Didn't Know|Knew It →