The compound xf3 containts 65% f (mass percentage). mw(x) = ?

The compound XF3 has a molar mass of  87.7 g/mol

The element x has an atomic mass of 30.7 u

This element can be P (phosphorus) and the compound will be PF3

Explanation:

Step 1: Data given

Compound XF3 has a mass % of 65% F

Step 2:

The sample has 65% mass percent, this is the ratio of the element (F) it's mass compared to the mass of the compound.

(Mass of F / mass of compound)*100% = 65 %

Step 3: Calculate molar mass of the compound

F has an atomic mass of  19u (Since there are 3x F the atomic mass is 3*19 = 57 u)

The compound XF3 has a molar mass of (X+57)g/mol

 ⇒ with X = the molar mass of compound x

Mass % of F = 65% = (3*19g/mol)/(X+57)g/mol

0.65 = (57/(X+57))

57 = 0.65*(X+57)

57 = 0.65X + 37.05

19.95 = 0.65X

X = 30.7 g/mol

This means the atomic mass of the element x is 30.7 u

To control this we can calculate the mass % of F

((3*18)/(30.7 + 3*18)) * 100% = 65%

The compound XF3 has a molar mass of  87.7 g/mol

The element x has an atomic mass of 30.7 u

This element can be P (phosphorus) and the compound will be PF3

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

is there any options? maybe im just not seeing them but i need the options to

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