Methane is also known as natural gas, and its combustion is a very common reaction: CH4 + 2 O2 → CO2 + 2 H2O. Remember that we can use stoichiometry if we know the correct coefficients. So, which of these conversion factors will NOT work for this reaction? NOTE: All numbers located immediately after elemental symbols should be considered subscripts.

A. 1 mole O2 = 32.00 g

B. 2 mole H2O = 18.02 g

C. 2 mole O2 = 1 mole CO2

D. 1 mole CH4 = 2 mole H2O

E. none of the above

2 mole H2O = 18.02 g will not work.

Explanation:

Let us check the options one by one:

1 mole of O2 weighs 32 g.

⇒Hence option A is correct.

1 mole of H2O weighs 18 g.

⇒Hence option B is wrong.

From the balanced equation we can say:

1 mole of CH4 reacts with 2 moles of O2 to give 1 mole of CO2 and 2 moles of H2O.

⇒Hence option C and D are correct.

Option B: 2 mole H2O = 18.02 g is not correct.

Explanation:

Step 1: The balanced equation

CH4 + 2O2 → CO2 + 2H2O

Step 2: Data given

Molar mass of O2 = 32 g/mol

Molar mass of H2O = 18.02 g/mol

Molar mass of CH4 = 16.04 g/mol

Step 3: Calculate number of mol

For 1 mol of CH4 we need 2 moles of O2 to produce 1 mol of CO2 and 2 moles of H2O

This means option C is correct: For 2 moles O2 consumed, we'll get 1 mol of CO2 produced.

Also Option D is corect: For 1 mole of CH4 we get 2 moles of H2O

Mass = moles * molar mass

Mass of 1 mole O2 = 1 mol * 32.00 g/mol = 32.00 grams

Mass of 2 moles H2O = 2 mol * 18.02 g/mol = 36.04 grams (This means option B is not correct.)

Option B: 2 mole H2O = 18.02 g is not correct.