Unit 5 & 6 Intro to Chemical Reactions and Equations Study Guide

When the following equation is balanced, what is the coefficient of Al?
___Al + ___O2 🡪 ___Al2O3

• 1

• 2

• 3

• 4

Answer explanation

To balance the equation, please count the atoms and make sure you have the same number of Al and O on each side of the arrow.

Tags

NGSS.HS-PS1-7

For the equation, identify the reactants and the products.

___Al + ___O2 🡪 ___Al2O3

• Reactants: Al and O2
  Products: Al2O3

• Reactants: Al
  Products: O2 and Al2O3

• Reactants: Al2O3
  Products: Al and O2

• Reactants: Al2O3 and O2
  Products: Al

Answer explanation

Reactants are the inputs, and they are located on the left side of the arrow. Products are the outputs, and they are located on the right side of the arrow.

Tags

NGSS.HS-PS1-7

If you started with 53.96 g of Al and 95.8 g of O2, what would the mass of the product be?

___Al + ___O2 🡪 ___Al2O3

• 5,169.37 g

• 41.84 g

• 149.76 g

• 53.96 g

Answer explanation

Use the Law of Conservation of Mass. The mass of the reactants should match the mass of the products.

Tags

NGSS.HS-PS1-7

Choose the coefficients that correctly balance the following equation:

___C₂H₆ + ___O₂ ⟶ ___CO₂ + ___H₂O

• 1, 3, 2, 3

• 1, 4, 2, 6

• 2, 7, 4, 6

• 2, 7, 4, 2

Answer explanation

To balance the equation, please count the atoms and make sure you have the same number of C, H, and O on each side of the arrow.

Tags

NGSS.HS-PS1-7

What type of reaction is this?

___C2H6 + ___O2 🡪 ___CO2 + ___H2O

• Single Replacement

• Synthesis

• Double Replacement

• Combustion

Answer explanation

Which reaction reacts with oxygen to produce carbon dioxide and water?

A student is performing an experiment where 2.4 g of metallic aluminum is being added to 30 mL of copper sulfate. The student observes that a reddish brown substance forms, the test tube gets hot, and the amount of aluminum seems to decrease. Which of the following is the BEST way to tell that a chemical reaction has occurred between these two reactants?

• The reaction volume is approximately 32.5 mL

• The remaining aluminum is shiny and silver in color

• There is condensation on the test tube

• A reddish brown substance appears

Answer explanation

Various signs of a chemical reaction include:

1. Change in Color.

2. Formation of a Gas.

3. Formation of a Precipitate.

4. Change in Odor.

5. Change in Temperature.

6. Something is Burning.

7. Light is Being Produced.

Tags

NGSS.MS-PS1-2

Balance the following equation:

___Na + ___H₂O ⟶ ___NaOH + ___H₂

• 1, 1, 1, 1

• 2, 2, 2, 1

• 2, 2, 2, 2

• 1, 2, 1, 2

Answer explanation

To balance the equation, please count the atoms and make sure you have the same number of Na, O, and H on each side of the arrow.

Tags

NGSS.HS-PS1-7

What type of equation is this?

___Na + ___H₂O ⟶ ___NaOH + ___H₂

• Decomposition

• Single Displacement

• Double Displacement

• Synthesis

Answer explanation

Na + H₂O ⟶ NaOH + H₂

A + BC ⟶ AB + C

Sort the following into the correct type of chemical reaction.

Groups:

(a) Synthesis

,

(b) Decomposition

,

(c) Combustion

,

(d) Double Replacement

• 
• 
• 
• 
• 
• 

Tags

NGSS.HS-PS1-2

A student is doing an experiment where they mix vinegar and baking soda. Once mixed, bubbles form as CO2 is produced. Using the balanced chemical equation and the data table below, determine which of the following statements explains why the substances in the beaker before the reaction is different from the mass after the reactions.

• The baking soda and vinegar reacted slowly

• The CO2 gas that escaped the beaker is not included in the measurement

• 1. The baking soda and vinegar do not completely react

• 1. The mass was destroyed in the reaction

Answer explanation

The Law of Conservation of Mass states that the mass of the reactants should match the mass of the products. What is something that would cause the mass to differ?

Tags

NGSS.HS-PS1-7