Counting Atoms and Chemical Reactions

Serotonin is a chemical substance that acts as a neurotransmitter. It helps relay messages in the human brain. The formula for one molecule of serotonin is shown below.

C₁₀H₁₂N₂O

How many atoms in all are in a molecule of serotonin?

• 1

• 4

• 25

• 24

Tags

NGSS.MS-PS1-1

Identify the reactants in the chemical equation below.

NaOH + HCl --> NaCl + H₂O

• NaCl and H₂O

• HCl and NaCl

• NaOH and HCl

• HCl and H₂O

Tags

NGSS.MS-PS1-2

Which of the following chemical equations is balanced?

• 3Na + Cl₂ --> 3NaCl

• CO₂ + H₂O --> C₆H₁₂O₅ + O₂

• 2H₂O + O₂ --> 2H₂O + OH

• 3AgBr + GaPO₄ --> Ag₃PO₄ + GaBr₃

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The formula for Glucose is C₆H₁₂O₆. How many atoms does glucose contain?

• 6

• 12

• 24

• 48

Tags

NGSS.MS-PS1-1

How many copper (Cu) atoms are there in the Cu(NO₃)₂ molecule below?

Cu + 2AgNO₃ ---> 2Ag + Cu(NO₃)₂

• 6

• 1

• 5

• 2

Tags

NGSS.MS-PS1-1

A student mixes two solutions (liquids), planning to produce carbon dioxide. Which of the following is the BEST evidence that a chemical reactions as taken place and carbon dioxide (gas) has been formed.

• Color Change

• Temperature Change

• Formation of bubbles

• formation of a solid

Tags

NGSS.MS-PS1-2

How many atoms are in one molecule of baking soda, NaHCO₃?

• 12

• 4

• 6

• 5

Tags

NGSS.MS-PS1-1

Which of the following are types of evidence that tells us a chemical change has taken place?

CLICK ALL THAT ARE CORRECT!

• Color change

• Light is produced

• The substance breaks into tiny pieces

• Temperature change

• Bubbles are formed

Tags

NGSS.MS-PS1-2

When two liquids are mixed together and a solid is formed, what do we call it?

• Metal

• A rock

• Precipitation

• Precipitate

Tags

NGSS.MS-PS1-2

Which of the following lists all of the elements that are present in a molecule of potassium carbonate, K₂CO₃?

• Phosphate and calcium

• Potassium, carbon, and oxygen

• Argon and Oxygen

• Phosphorus, oxygen, and calcium

Tags

NGSS.MS-PS1-1