The density of glycerin is 1.26 g/cm3. how many pounds/foot3 is this ? use the conversion rates of 454g/1 pound and 28,317cm3/1foot3 express your answer to the correct number of significant figures

78.6 lb/ft³  

Step-by-step explanation:

Let's do this in steps.

1. Convert grams to pounds

D = (1.26 g/1 cm³) × (1 lb/454 g)

   = 2.775 × 10⁻³ lb/cm³

2. Convert cubic centimetres to cubic feet

D = (2.775 × 10⁻³ lb/1 cm³) × (28 317cm³/1 ft³)

   = 78.6 lb/ft³

P =  14.1 atm    

Explanation:

Given data:

Mass of methane = 64 g

pressure exerted by water vapors = ?

Volume of engine = 24.0 L

Temperature = 515 K

Solution:

Chemical equation:

CH₄ + 2O₂      →      CO₂ + 2H₂O + energy

Number of moles of methane:

Number of moles = mass / molar mass

number of moles = 64 g/ 16 g/mol

Number of moles = 4 mol

Now we will compare the moles of water vapors and methane.

              CH₄          :            H₂O  

                 1            :             2

                 4            :         2/1×4 = 8 mol

Pressure of water vapors:

PV = nRT

R = general gas constant = 0.0821 atm.L/mol.K

P = 8 mol × 0.0821 atm.L/mol.K× 515 K / 24.0 L

P = 338.25 atm.L/ /  24.0 L

P =  14.1 atm