Counting Atoms Quiz

What is the coefficient for Hydrogen in the chemical equation 2H₂ + O₂ → 2H₂O?

• 4

• 3

• 1

• 2

Answer explanation

The question is asking for the coefficient not the total number of Hydrogen atoms

Tags

NGSS.MS-PS1-5

How many Carbon atoms are there in the chemical formula CH₄?

• 4

• 1

• 2

• 3

Answer explanation

If there is no subscript next to an element, we can put an imaginary 1 there

Tags

NGSS.MS-PS1-1

What are the subscripts in the chemical formula Na₅Cl₃?

• 1 and 3

• 5 and 3

• 5 and 2

• Na and Cl

Tags

NGSS.MS-PS1-1

How many carbon atoms are there in the chemical formula 2C₆H₁₂O₆?

• 12

• 18

• 6

• 24

Answer explanation

Multiply the subscript for C by the coefficient. 6x2 = 12 so we have 12 total carbon atoms.

Tags

NGSS.MS-PS1-1

What is the coefficient of the product in the equation 2H₂ + O₂ → 3H₂O?

• 1

• 2

• 3

• 4

Answer explanation

The product is always on the right hand side of the arrow. The coefficient is 3

Tags

NGSS.MS-PS1-5

How many oxygen atoms are there in the chemical formula CO?

• 3

• 1

• 4

• 2

Tags

NGSS.MS-PS1-1

How many Oxygen elements are in the chemical formula Mg(OH)₂?

• OH

• Mg

• H

• 2

Tags

NGSS.MS-PS1-1

What is the product in the chemical equation 2H₂ + O₂ → 2H₂O?

• 2H₂O

• H2O2

• H2O3

• HO

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

How many Sulfur atoms are in the chemical formula 4H₂SO₃?

• 2

• 4

• 3

• 1

Tags

NGSS.MS-PS1-1

How many Mg atoms are on the reactant side of the chemical formula 2Mg + O₂ → 2MgO?

• 1

• 2

• 3

• 4

Answer explanation

The reactants are always on the left hand side of the arrow. The coefficient tells us we have 2 elements of Mg.

Tags

NGSS.MS-PS1-1