How many moles are in 7.5 g of C3H11NO3 (Vitamin B6)

7.5g Vitamin B6 => 0.069 mole Vitimin B6 (C₃H₁₁NO₃)

Explanation:

To convert gram value to a mole value, divide formula weight of substance of interest into gram-value given; that is,  ...

        moles = mass of substance (g) / formula weight (g/mol)

formula weight of B6 =>∑ 3C + 11H + 1N + 3O

    = 3mol(12g/mol) + 11mol(1g/mol) + 1mol(14g/mol) + 3mol(16g/mol)

    = 36g + 11g + 14g +48g = 109g/mol

given 7.5g of Vitamin B6 converted to moles V6

= 7.5g / 109g/mol = 0.069 mol Vitamin B6

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.

b.

the accuracy of the data.