Hydrogen fluoride will react with glass (silicon dioxide. S_iO_2) according to the equation below What mass of HF is required to react completely with 16 0 g of glass? (Molar masses; Si 28 09 g/mol F 19 00 g/mol H. 1.01 g/mol O, 16.00 g/mol] 4HF(g) + SiO_2(s) --> SiF_4(g) + 2H_2O(g)
A. 5.33 g
B. 21.3 g
C. 64.0 g
D. 80.0 g
E. 320 g

21.3 g. Option B

Explanation:

The reaction is:

4HF(g) + SiO₂(s) → SiF₄(g) + 2H₂O(g)

We analysed it and it is correctly balanced.

4 moles of hydrogen fluoride react to 1 mol of silicon dioxide in order to produce 1 mol of silicon fluoride and 2 moles of water vapor.

We determine molar mass of each reactant:

HF → 1.01 g/mol + 19 g/mol = 20.01 g/mol

SiO₂ → 16 g/mol . 2 + 28.09 g/mol = 60.09 g/mol

We convert mass to moles: 16 g . 1 mol /60.09g = 0.266 moles of glass

Ratio is 1:4. 1 mol of glass react to 4 moles of HF

Our 0.266 moles may react to (0.266 . 4) / 1 = 1.07 moles of gas

We convert moles to mass: 1.07 mol . 20.01 g/mol = 21.3 g

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.