Chapter test Practice 1 Balancing of Chemical Equation

What does the arrow in a chemical equation represent?

• It shows the balance between mass and energy.
• It is read as "yields" and indicates the formation of products.
• It demonstrates the conservation of mass and energy.
• It represents an equal sign in all chemical reactions.

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NGSS.MS-PS1-5

Why must the reactants in a chemical equation equal the products?

• To satisfy the law of conservation of energy.
• To show that chemical equations are reversible.
• To comply with the law of conservation of mass.
• To indicate that the products are more stable than the reactants.

Tags

NGSS.MS-PS1-5

How does the Law of Conservation of Mass apply to chemical reactions?

• It ensures the products are more stable than the reactants.
• It prevents energy from being lost during the reaction.
• It requires the same number of atoms on both sides of the equation.
• It balances the charges of the molecules involved.

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NGSS.MS-PS1-1

NGSS.MS-PS1-5

What does the Law of Conservation of Mass state?

• Mass can be created but not destroyed in chemical reactions.
• Mass and energy are interchangeable in chemical equations.
• Mass cannot be created or destroyed, only rearranged.
• Mass is always destroyed to form new compounds.

Tags

NGSS.MS-PS1-5

In the reaction indicated in the photo,how does the Law of Conservation of Mass apply?

• The total number of atoms remains the same on both sides of the equation.
• The products gain more mass than the reactants during the reaction.
• The reactants lose mass as they combine to form the final products.
• The reaction creates new atoms to balance both sides of the equation.

Tags

NGSS.MS-PS1-5

What is the purpose of coefficients in a chemical equation?

• To show the ratio of reactants and products in the equation.
• To change the chemical formula of the substances involved.
• To indicate the number of individual atoms in a compound.
• To represent the charge of the chemical compounds in the equation.

Tags

NGSS.MS-PS1-5

Why can’t subscripts be changed when balancing a chemical equation?

• Changing subscripts alters the coefficients in the equation.
• Changing subscripts creates new atoms in the reaction.
• Subscripts are part of the set chemical formula of a substance.
• Subscripts apply to the entire chemical formula, not individual elements.

Tags

NGSS.MS-PS1-5

What is the purpose of listing atoms on both the reactants and products side of a chemical equation?

• To determine the overall charge of the reaction.
• To compare the number of atoms and ensure they are balanced.
• To identify the energy levels of each element in the reaction.
• To prioritize compounds with more atoms during balancing.

Tags

NGSS.MS-PS1-5

Why should you start with single elements first when balancing a chemical equation?

• Single elements are easier to balance and do not affect other compounds.
• Single elements are the most reactive and should be balanced first.
• Starting with single elements increases the number of coefficients used.
• Single elements must be balanced after compounds with multiple elements.

When balancing the equation in the photo, which element should you balance first?

• Carbon, because it is present in only one compound on the reactant side.
• Hydrogen, because it is found in both reactants and products.
• Oxygen, because it is present in multiple compounds on both sides.
• Carbon, because it is more reactive than hydrogen.