Combustion equation of n-hexane:
2C₆H₁₄ + 19O₂ → 12CO₂ + 14H₂O
a)
Assuming we have 100 moles of air,
Oxygen = 20.9 moles
n-hexane required = 20.9/19 x 2
= 2.2 moles
LFL = Half of stoichometric amount = 2.2 / 2 = 1.1
LFL n-hexane = 1.1%
b)
1.1 volume percent required for LFL
1.1% x 1
= 0.0011 m³ of n-hexane required
0.0788 will be the number of moles of silver in coin.
<h3><u>How to find the number of moles?</u></h3>
A mole is the mass of a material made up of the same number of fundamental components. Atoms in a 12 gram example are identical to 12C. Depending on the material, the fundamental units may be molecules, atoms, or formula units.
A mole fraction shows how many chemical elements are present. The value of 6.023 x 10²³ is equivalent to one mole of any material (Avagadro's number). It can be used to quantify the chemical reaction's byproducts. The symbol for the unit is mol.
The number of moles formula is denoted by the following expression:
Number of moles = Mass of substance/mass of one mole
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Answer:
Kinetic energy: 
Velocity: 
Explanation:
From the equations of the photo-electric effect,
We know:
Where,
1.
is the Planck's constant which is 
2.
are the frequency of light emitted and threshold frequencies respectively.
3.
is the kinetic energy of the electrons emitted.
By fact, we come to know that the threshold frequency of Zn is 300nm
And also 
Where ,
1. 
is the speed of light 
2.
is the wavelength.
Thus,
Now to find velocity:
Molar mass of NaHCO3 is 83.9. moles of Na...O3= 5.8/83.9
=0.0691
for every mole of Na..O3 there are 3 O
n(O) = n(NaHCO3) x3
= 0.207
mass of O is the moles x molar mass (16)
therefore the mass of O is 3.3 grams
I would say copper, silver, and tin, since an alloy is a mixture of metals and metalloids.
