Counting Atoms Practice Set 1

What does the subscript in a chemical formula tell you?

• How many molecules are present

• How many atoms are present

• How many elements are present

• How many neutrons are present

Answer explanation

How many atoms of Iron are in this compound?

• 1

• 2

• 3

• 4

Answer explanation

Tags

NGSS.MS-PS1-1

A substance made up of atoms of two or more different elements joined by chemical bonds

• Molecule

• compound

• polar covalent bond

• nonpolar covalent bond

Tags

NGSS.MS-PS1-1

Calculate the number of Oxygen atoms in Al(OH)₃

• 1

• 2

• 3

• 4

Answer explanation

Tags

NGSS.MS-PS1-1

How many total POTASSIUM atoms are in this formula?

• 8

• 2

• 4

• 12

Answer explanation

Tags

NGSS.MS-PS1-1

Coefficients in chemical formulas...

• Multiply just the first atom

• Add to the subscripts at the end of the molecule

• Multiply elements without subscripts

• Multiply EVERYTHING!

Number of H in 3(NH₄)₂CrO₄

• 4
• 2
• 8
• 24

Tags

NGSS.MS-PS1-1

Which is the correct formula for:
 three hydrogen (H)
one sulfur (S)
four oxygen (O)

• H₃SO₄
• HSO₄
• H₄S₃O
• H₂O

Tags

NGSS.MS-PS1-1

How many atoms of Oxygen are in Fe(NO₃)₃ ?

• 6
• 3
• 9
• 1

Tags

NGSS.MS-PS1-1

Which one is the coefficient 4H₂O?

• 4

• H

• 2

• O