Questions 4-6: Use the following Molar Masses: H2: 2.02 g/mol Oz: 32.00 g/mol H2O: 18.02 g/mol
5) What mass of oxygen is needed to completely react
with 32.0 g of hydrogen?
2 Hz O2 → 2 H2O
+
32 g H2
х
x
x
= 329 H2
= 1g 42
= 2.02 g H2
= 1 mol H2
* 2.02 mol H2
- 2 mol H2
# 1 mol O2
- 2 mol O2
# 32 mol Oz
3 32 mol O2
=> 32 g 02
- 1 g 02
= 1013 g 02
: 0.248 g 02
253.4 g 02

Mass =   253.4 g

Explanation:

Given data:

Mass of oxygen required = ?

Mass of hydrogen available = 32.0 g

Solution:

Chemical equation:

2H₂ + O₂     →       2H₂O

Number of moles of hydrogen:

Number of moles = mass/molar mass

Number of moles = 32.0 g/ 2.02 g/mol

Number of moles = 15.84 mol

Now we will compare the moles of hydrogen and oxygen:

                  H₂         :           O₂

                   2          :           1

              15.84        :         1/2×15.8 = 7.92 mol

Mass of oxygen required:

Mass = number of moles × molar mass

Mass = 7.92 mol × 32.00 g/mol

Mass =   253.4 g

answer carbon and three oxygen atoms;