Chemical Equations and Reactions Review

What is the coefficient of the oxygen molecule in the elephant toothpaste equation?
2 H₂O₂ -> 2 H₂O + O₂

• 0
• 1
• 2
• 4

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What do you call the substances on the left side of a chemical equation?

• yield
• products
• reactants
• compounds

Tags

NGSS.MS-PS1-1

What is true of this chemical equation?

• it is balanced
• it is unbalanced
• it produces an organic substance

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

A coefficient tells you...

• the # of atoms in the entire equation
• the # of elements in the equation
• the # atoms of the element it sits behind
• the # of molecules of that substance

Tags

NGSS.HS-PS1-7

The Law of Conservation of Mass proves that -

• the number of atoms in a chemical reaction does not change
• there are more atoms on the reactant side than the product side
• there are more atoms on the product side than the reactant side
• no new matter can be made

Tags

NGSS.MS-PS1-5

Which of the following proves the Law of Conservation of Mass?

• thermal energy is produced
• a balanced chemical equation
• chemoluminescence
• formation of a precipitate

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which would indicate a chemical equation is balanced?

• If the number of atoms in the reactants is the same as the number of atoms in the products

• If the atoms have ionic OR covalent bonds

• If the atoms have full valence shells

• If the total energy has remained the same

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What coefficient should go in the last blank space in order for the equation to be balanced?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

How many sulfur atoms are present in this molecule?

• 4

• 3

• 12

• 1

Tags

NGSS.MS-PS1-1

When two substances were combined, bubbles were produced and the temperature dropped.  This most likely means that:

• a chemical reaction took place
• the two substances had low boiling points
• one substance dissolved in the other
• the two substances are non-reactive

Tags

NGSS.MS-PS1-2