Mrs. Lions explains how to count atoms in chemical compounds using coefficients and subscripts. She introduces the concept with barium chloride and provides examples with sodium oxide, barium nitrate, aluminum chloride, and ammonium sulfate. The video covers how coefficients and subscripts affect the number of atoms in a compound, including complex cases with parentheses.

What does a coefficient in a chemical formula indicate?

• The total weight of the compound

• The number of atoms in each element

• The charge of the compound

• The number of molecules of the compound

If there is no subscript written for an element in a compound, how many atoms of that element are present?

• It varies depending on the element

• Two

• One

• Zero

Tags

NGSS.MS-PS1-1

What does the subscript in a chemical formula represent?

• The number of protons

• The number of molecules

• The ionic charge of the element

• The number of atoms of the element it follows

In the compound Na2O, how many oxygen atoms are present?

• Four

• Two

• Three

• One

Tags

NGSS.MS-PS1-1

For the compound Ba(NO3)2, how many nitrogen atoms are there?

• Four

• Two

• One

• Three

Tags

NGSS.MS-PS1-1

In the formula Ba(NO3)2, how many oxygen atoms are present?

• Three

• Nine

• Six

• Twelve

Tags

NGSS.MS-PS1-1

In the compound Al4Cl3, how many chlorine atoms are present?

• Twelve

• Four

• Sixteen

• Three

Tags

NGSS.MS-PS1-1

In the compound 4AlCl3, how many aluminum atoms are there?

• Three

• Four

• Twelve

• Sixteen

Tags

NGSS.MS-PS1-1

What is the total number of hydrogen atoms in the compound with the formula 2(NH4)2S?

• Eight

• Twelve

• Four

• Sixteen

Tags

NGSS.MS-PS1-1

How many sulfur atoms are in the compound 2(NH4)2S?

• Two

• Four

• Three

• One

Tags

NGSS.MS-PS1-1