Understanding the Concepts

Balance each of the following by adding coefficients:

Balance each of the following by adding coefficients:

If red spheres represent oxygen atoms and blue spheres represent nitrogen atoms

a. Write the formula for each of the reactants and products.

b. Write a balanced equation for the reaction.

If blue spheres represent nitrogen atoms and purple spheres represent iodine,

a. Write the formula for each of the reactants and products.

b. Write a balanced equation for the reaction.

If green spheres represent chlorine atoms, yellow-green spheres represent fluorine atoms, and white spheres

represent hydrogen atoms,

a. Write the formula for each of the reactants and products.

b. Write a balanced equation for the reaction.

If green spheres represent chlorine atoms and red spheres represent oxygen atoms

a. Write the formula for each of the reactants and products.

b. Write a balanced equation for the reaction.

If blue spheres represent nitrogen atoms and purple spheres represent iodine atoms

a. Write the formula for each of the reactants and products.

b. Write a balanced equation for the reaction.

Practice Problems

1. Balance the following chemical reaction:

P4(s) + O2(g) P4O10(s)

a. P4(s) + O10(g) P4O10(s)

b. 2P4(s) + 4O2(g) 2P4O10(s)

c. P4(s) + 5O2(g) P4O10(s)

d. P4(s) + 4O2(g) P4O10(s)

2. Balance the following chemical reaction:

C4H8(g) + O2(g)

∆→ CO2(g) + H2O(g)

a. C4H8(g) + 3O2(g)

∆→ 4CO2(g) + 4H2O(g)

b. C4H8(g) + 6O2(g)

∆→ 4CO2(g) + 4H2O(g)

c. 2C4H8(g) + 6O2(g)

∆→ 4CO2(g) + 6H2O(g)

d. 2C4H8(g) + 3O2(g)

∆→ 3CO2(g) + 3H2O(g)

Section 7.2 – Types of Reactions

Goal: Identify a reaction as a combination, decomposition, single replacement, double replacement, or

combustion reaction.

Summary

Understanding the Concepts

Identify each of the following as: combination, decomposition, single replacement, double replacement, or

combustion. (If it helps, use the equations you wrote for Understanding the Concepts for section 7.1. These are

the same reactions.)

Section 7.5 – Molar Mass and Calculations

Goal: Calculate the molar mass for a substance given its chemical formula; use molar mass to convert between

grams and moles.

Summary:

Calculating Molar Mass:

The molar mass of a compound is the sum of the molar mass of each element in it chemical formula multiplied

by it subscript in the formula. The molar masses of individual elements are found on the periodic table as the

atomic mass (the decimal number under the symbol).

Example:

Pinene, C10H16, which is found in pine tree sap and essential oils, has anti-inflammatory properties. Calculate

the molar mass for pinene.

Answer:

Using Molar Mass as a Conversion Factor

• The molar mass of an element is its mass in grams per mole equal numerically to its atomic mass.

• The molar mass of a compound is its mass in grams per mole equal numerically to the sum of the masses

of its elements.

• Molar mass is used as a conversion factor to convert between the moles and grams of a substance.

Example:

The frame of a bicycle contains 6500 g of aluminum. How many moles of aluminum are in the bicycle frame?

Answer:

\

Understanding the Concepts:

Using the models of the molecules (black = C, white = H, yellow =S, green = Cl) determine each of the

following for models of the compounds.

a. molecular formula

b. molar mass

c. number of moles in 10.0 g

Using the models of the molecules (black = C, white = H, yellow = S, Red = O) determine each of the

following for the models of the compounds

a. molecular formula

b. molar mass

c. number of moles in 10.0 g

Practice Problems:

29. Calculate the molar mass of the following:

a. FeSO4 _______ g/mol

b. C7H5NO3S _______ g/mol

c. (NH4)2CO3 _______ g/mol

d. O2 _______ g/mol

e. Fe(ClO4)3 _______ g/mol

30. Calculate the mass in grams for 1.50 moles K

a. 11.2 g

b. 39.1 g

c. 26.1 g

d. 58.6 g

e. 28.5 g

31. Calculate the mass in grams of 2.5 moles of C.

a. 24.0 g

b. 30.0 g

c. 4.80 g

d. 15.0 g

e. 16.2 g

32. Calculate the number of grams in 5.00 moles of C2H6O.

a. 212 g

b. 29.0 g

c. 460 g

d. 230 g

e. 46.1 g

33. Calculate the number of grams in 0.488 mole of C3H6O3.

a. 29.0 g

b. 90.1 g

c. 44.0 g

d. 57.3 g

e. 185 g

Answer:

Calculation of theoretical yield:

Calculation of percent yield:

Understanding the Concepts

If green spheres represent chlorine atoms, yellow-green spheres represent fluorine atoms, and white spheres represent

hydrogen atoms, (7.1, 7.8)

a. Write a balanced equation for the reaction.

b. Identify the limiting reactant.

If blue spheres represent nitrogen atoms and white spheres represent hydrogen atoms, (7.1, 7.8)

a. Write a balanced equation.

b. Identify the diagram that shows the products.