The focal length, like you said it's the distance between the FOCAL point and the mirror.
Hope this helps.... :)
A combustion involves a chemical reaction.
Answer:
Mass = 13.23 g
Explanation:
Given data:
Mass of oxygen = 48.0 g
Mass of propane burn = ?
Solution:
Chemical equation:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Number of moles of oxygen:
Number of moles = mass/molar mass
Number of moles = 48.0 g/ 32 g/mol
Number of moles = 1.5 mol
now we will compare the moles of propane and oxygen.
O₂ : C₃H₈
5 : 1
1.5 : 1/5×1.5 = 0.3 mol
Mass of propane burn:
Mass = number of moles × molar mass
Mass = 0.3 mol × 44.1 g/mol
Mass = 13.23 g
Molality is the number of moles of solutes in 1 kg of solvent.
the molality of solution to be prepared is 2.0 molal.
therefore 2 moles in 1 kg water.
the mass of Li₂S required is - 46 g/mol x 2.0 mol = 92 g
the mass in 1 kg of solvent is - 92 g
Therefore mass of Li₂S required in 1600.0 g is - 92 g/kg x 1.6 kg = 147.2 g
