Question

The amount of oxygen required to burn completely 510g of octane is

Answer 1

Now, Octane,

The formula of octane is C8H18.

Given mass = 570 g

Molar mass = 8 × 12 + 18 × 1 = 96 + 18 = 114 g

No. of moles = given mass / Molar mass = 570 g / 114 g = 5 moles

Now, the equation formed is

C8H18 + O2 - - - - - CO2 + H2O

After balancing the equation, we get

C8H18 + 25/2 O2 - - - - - - 8CO2 + 9H2O

From this equation we can say that,

1 mole of C8H18 reacts with 25/2 moles of O2

Also, 5 moles of C8H18 reacts with 25/2 × 5 moles of O2

5 moles of C8H18 = 62.5 moles of O2

Now, Oxygen, O2

Molar mass = 2 × 16 = 32 g

No. of moles = 62.5 moles

Given mass =?

No. of moles = given mass / Molar mass

Given mass = no. of moles × Molar mass = 62.5 × 32 = 2000 g

Physics - - - - - -

Let A = 10N

B = 6N

Maximum force = A + B = 10 + 6 = 16 N

Minimum force = A - B = 10 - 6 = 4N

Now the vector sum lie between these values.

As I know the answer it is 8N.

Hope this helps you..