Counting Atoms In Compounds

How many TOTAL atoms H₂SO₄

7

How many TOTAL atoms Mg(C₂H₃O₂)₂

15

A compound with parenthesis. Pb(NO3)2, means you _________ number outside the parenthesis times the subscript ________ the parenthesis.

multiply, inside

A __________________ in chemistry is used to tell the reader how many of that element there are in a certain compound.

subscript

The 2 after the parenthesis indicates there are ______ sets of the element combination in the parenthesis. Pb(NO3)(NO3)

two

Number of K in KNO₃

1

NaCl If there is not a subscript listed, it is understood to be ____.

1(one)

HCl Hydrogen = ____ Chlorine = ____

1, 1

NaCl There is ____ atom of Sodium There is _____ atom of Chlorine

1, 1

NaHCO3 Sodium = ____ Hydrogen = ____ Carbon = ____ Oxygen= ____

1, 1, 1, 3

Practice! Mg(OH)2 Magnesium - 1 Oxygen - 2 Hydrogen - 2

1, 2, 2

Pb(NO3)2, In Counting the atoms, you would have the following: Lead - ___ Oxygen - ___ Nitrogen -___

1, 6, 2

Number of O in Al₂(SO₄)₄

16

2H2SO4 This means there are _____ compounds of Sulfuric Acid. H2SO4 H2SO4

2

Number of Al in Al₂(SO₄)₄

2

How many TOTAL atoms Al₂(SO₄)₄

22

How many TOTAL atoms H₂O

3

Number of O in KNO₃

3

Practice! (NH4)3PO4 Nitrogen = ____ Hydrogen = ____ Phosphorus = ____ Oxygen = 4

3, 12, 1,

Number of S in Al₂(SO₄)₄

4

Practice! 2H2O = Hydrogen = _____ Oxygen = _____

4, 2

2H2SO4 Counting the atoms: Hydrogen = ____ Sulfur = ____ Oxygen = ____

4, 2, 8

How many TOTAL atoms Ba(OH)₂

5

Practice! 3H3PO4 = Hydrogen = _____ Phosphorus = _____ Oxygen = _____

9, 3, 12

Each new element is identified by a capital letter Example: H2SO4

Hydrogen, Sulfur, Oxygen

2H2SO4 The ____________ represent the number of molecules that take part in the chemical reaction.

coefficients