How many molecules are there in 30.0 g of methane gas (CH4)?

a. 1.00 mole of molecules
b. 3.011 x 10^23 molecules
c. 1.13 x 10^24 molecules
d. 6.88 x 10^23 molecules
e. 30 molecules

We have 1.13 * 10^24 molecules in 30.0 grams CH4 (option C)

Explanation:

Step 1: Data given

Mass of CH4 = 30.0 grams

atomic mass C = 12.00 g/mol

atomic mass H = 1.01 g/mol

Step 2: Calculate molar mass CH4

Molar mass CH4 = 12 + 4*1.01 g/mol

Molar mass CH4 = 16.04 g/mol

Step 3: Calculate moles CH4

Moles CH4 = mass CH4 / molar mass CH4

Moles CH4 = 30.0 grams / 16.04 g/mol

Moles CH4 = 1.87 moles

Step 4: Calculate number of molecules

number of molecules =moles * number of Avogadro

number of molecules = 1.87 * 6.022 * 10^23 / moles

number of molecules = 1.13 * 10^24 molecules

We have 1.13 * 10^24 molecules in 30.0 grams CH4 (option C)