7th Grade 4th Nine Weeks Test

To balance a chemical equation, which of the following can be adjusted?

• Subscripts

• Coefficients

• Both A and B

• The reactants

The law that states that matter is never created or destroyed in a chemical reaction is known as the:

• Law of Attraction

• Conservation Law of Energy

• Law of Conservation of Mass

• Law of Combining Volumes

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Why is it important to balance chemical equations according to the Law of Conservation of Mass?

• To have the same number of atoms on both sides

• To predict the outcome of experiments

• To demonstrate the Law of Chemical Equilibrium

• To prove the Law of Definite Proportions

Tags

NGSS.MS-PS1-5

In the equation 2 AgNO3 → 2 Ag + O2 + 2NO2, the AgNO3 is a:

• Reactant

• Product

Tags

NGSS.MS-PS1-5

What does the arrow in a chemical equation represent?

• Change in state

• A reaction taking place

• Heat being applied

• The speed of the reaction

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

According to the equation CO + H2 → CH3OH, how many hydrogen atoms are on the right side of the equation?

• 2

• 4

• 3

• 1

If a chemical equation has unequal numbers of atoms on each side, one must:

• Change the subscripts

• Add or adjust coefficients

• Increase the temperature

• Add catalysts

Tags

NGSS.MS-PS1-5

Which of the following terms refers to the number that appears in front of a chemical formula in a balanced chemical equation?

• Formula

• Subscript

• Coefficient

• Molar mass

How many total oxygen atoms are found in the balanced equation: 4Na + O2 → 2Na2O?

• 2

• 3

• 4

• 6

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

The process of balancing a chemical equation involves ensuring that the equation obeys the:

• Avogadro's law

• Law of Conservation of Charge

• Law of Definite Proportions

• Law of Conservation of Mass

Tags

NGSS.MS-PS1-5