Day 3 STAAR

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?

• 4
• 5
• 24
• 25

How many atoms of oxygen are in a molecule of glucose (C₆H₁₂O₆)?

• 3
• 12
• 6
• 24

26  The chemical formula for sodium sulfate is Na₂SO₄. How many sulfur atoms are in the formula for sodium sulfate?

• 1
• 2
• 6
• 7

The equation below represents a chemical reaction that occurs in living cells.
C₆H₁₂O₆ + 6O₂ ⎯⎯→ 6CO₂ + 6H₂O + energy

How many atoms are represented in the reactants of this equation?

• 6
• 12
• 24
• 36

In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?

• H₃PO₄
• H₂SO₄
• HClO₃
• H₂O