Chemical Formulas and Subscripts

This video tutorial explains how to count atoms in chemical formulas, focusing on the role of subscripts and coefficients. It covers basic concepts of counting atoms when no subscripts or coefficients are present, and progresses to more complex scenarios involving polyatomic ions and coefficients. The tutorial provides examples to illustrate how to distribute subscripts and coefficients across chemical compounds, ensuring a balanced understanding of chemical equations.

What does it mean when a chemical formula has no coefficients or subscripts?

• The elements are in a gaseous state.

• The formula is incorrect.

• There is only one atom of each element.

• There are multiple atoms of each element.

In the formula MgCl2, how many chlorine atoms are present?

• Four

• Three

• Two

• One

What does a subscript in a chemical formula indicate?

• The number of atoms of the element it follows

• The number of molecules

• The charge of the element

• The state of the element

In the chemical equation 2H2O, how many hydrogen atoms are there in total?

• Two

• Four

• Six

• Eight

How many nitrogen atoms are in 3NH4Br?

• Twelve

• Four

• Three

• One

What does a coefficient in a chemical equation help to achieve?

• It changes the state of the elements.

• It balances the number of atoms on both sides of the equation.

• It indicates the charge of the elements.

• It shows the temperature at which the reaction occurs.

In the compound (NH4)2O, how many hydrogen atoms are there?

• Eight

• Four

• Twelve

• Sixteen

What does a subscript outside parentheses in a chemical formula indicate?

• It only applies to the first element inside the parentheses.

• It shows the state of the compound.

• It multiplies all subscripts inside the parentheses.

• It indicates the charge of the compound.

In the compound Ca3(PO4)2, how many oxygen atoms are present?

• Six

• Twelve

• Four

• Eight

How many barium atoms are in 2Ba(NO3)2?

• Four

• Three

• Two

• One