Answer:
a) 4869 kJ will be released
b) 43.86 g of octane
Explanation:
The heat of combustion is the amount of heat released when 1 mol of a substance reacts with enough oxygen .
Since the heat of combustion is per mol of combustible substance what we are required to do in this problem is calculate number moles in the reactions although in a different manner.
a) MW C3H6O = 158 g/mol
mol C3H6O = 158 g x 1 mol/58.08 g = 2.72
-1790 kJ/ mol x 2.72 mol = 4869 kJ
b) Here we are asked the mass of octane to produce 1950 kJ of heat knowing that per mol of octane we get 5074.1 kJ, then
1 mol / 5074.1 kJ x 1950 kJ = 0.384 mol
mass C8H18 = 0.384 mol x 114.23 g/mol = 43.86 g
Use stoichiometry 3.75moles k* 39.10g k\1 mole k= 146.63g k
Answer:
0.0125mol
Explanation:
Molarity (M) = number of moles (n) ÷ volume (V)
n = Molarity × Volume
According to this question, a 0.05M solution contains 250 mL of NaOH. The volume in litres is as follows:
1000mL = 1L
250mL = 250/1000
= 0.250L
n = 0.05 × 0.250
n = 0.0125
The number of moles of NaOH is 0.0125mol.
Answer:
36.3
Explanation:
The full answer would be 36.3426, but because of the 0.21, you round it down to 3 sig figs.
