What’s the answer please gelp

Option A. 1.8×10²⁴ molecules.

Explanation:

Data obtained from the question include:

Number of mole of methane = 3 moles

Number of molecules of methane =?

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules.

Thus, 1 mole of methane equally contains 6.02×10²³ molecules.

With the above information in mind, we can obtain the number of molecules in 3 moles of methane as follow:

1 mole of methane contains 6.02×10²³ molecules.

Therefore, 3 moles of methane will contain = 3 × 6.02×10²³ = 1.8×10²⁴ molecules.

Thus, 3 moles of methane contains 1.8×10²⁴ molecules.

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer