Lesson 1 - Review Chemical Equations

To balance a chemical equation, it may be necessary to adjust the

• formulas of the products

• subscripts

• coefficients

• number of products

Tags

NGSS.HS-PS1-7

Name the part in red:

2 H₂ + O₂ --> 2 H₂O

• coefficient

• formula unit

• superscript

• subscript

At the end of chemical reactions, what is the total mass of the products compared to the total mass of the reactants?

• the product is doubled

• the product is half the mass of the reactants

• the mass is the same

• the mass changes depending on the reaction

Tags

NGSS.MS-PS1-5

In the chemical equation 2 H₂O₂(aq) → 2 H₂O(l) + O₂(g), the O₂ is a

• reactant

• compound

• product

• solid

Tags

NGSS.MS-PS1-2

The products of a reaction have the same ________as the reactants.

• molecule

• atoms

• subscripts

• coefficients

Tags

NGSS.MS-PS1-5

The substances listed on the left side of a chemical equation are the

• starting materials

• reactants

• products

• precipitates

• reagents

Tags

NGSS.MS-PS1-5

What will weigh more when a chemical change is complete? The reactants before the chemical reaction, or the product after the reaction is complete?

• They both will weigh the same according to the law of conservation of matter.

• The product always weighs more than the reactant

• The reactant will weigh more than the product

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What is the number before a chemical formula called?

Ex: 2 H₂ + O₂ --> 2 H₂O

• coefficient

• subscript

• exponent

• none of the above

Which equation best represents the reaction shown?

• C₃H₆O₉ --> C₃H₆O₉

• C₃H₆O₉ --> C₃O₆ + H₆O₃

• 3 H₂CO₃ --> 3 CO₂ + 3 H₂O

• H₂CO₃ --> CO₂ + H₂O

Which equation best represents the reaction shown?

• CH₃SH + H₂O₂ --> CH₃S₂CH₃ + 2 H₂O

• 2 CH₃SH + H₂O₂ --> 2 H₂O + 2 CH₃S

• 2 CH₃SH + H₂O₂ --> 2 H₂O + CH₃S₂CH₃

• C₂H₆S₂H₂ + H₂O₂ --> C₂H₆S₂ + 2 H₂O