1) Chemical equation
16Fe(s) + 3S8(s) ---> 8Fe2S3
2) Molar ratios:
16 mol Fe : 3 mole S8 : 8 mol Fe2S3
3) Convert masses in grams to number of moles
number of moles = mass in grams / molar mass
a) iron, Fe
mass = 3.0 g
atomic mass = 55.845 g/mol
=> number of moles of Fe = 3.0g / 55.845 g/mol = 0.0537 mol
b) Sulfur, S8
mass = 2.5 g
molar mass = 8*32.065 g/mol = 256.52 g/mol
=> number of moles of S8 = 2.5g / 256.52 g/mol = 0.009746 mol
4) Limiting reactant
Theoretical ratio actual ratio
16 mol Fe / 3 mol S8 0.0537 mol Fe / 0.009746 mol S8
5.33 5.50
So, there is a little bit more Fe than the theoretical needed to react all the S8, which means the S8 is the limiting reactant.
5) Calculate the number of moles of iron (III) produced with 2.5 g (0.009746 moles) of S8
3moles S8 / 8 moles Fe2S3 = 0.009746 moles S8 / x
=> x = 0.009746 * 8 / 3 moles Fe2S3 = 0.026 moles Fe2S3
6) Convert 0.026 moles Fe2S3 into grams
mass in grams = number of moles * molar mass
molar mass of Fe2S3 = 207.9 g/mol
mass = 0.026 mol * 207.9 g/mol = 5.40 g
7) Answer: option D)
A.He
because He 's molecular weight is small than each other
Force... I hope this helped you
Answer:
236.9g
Explanation:
Given parameters:
Volume of gas = 81.3L
Pressure of gas = 204kPa
temperature of gas = 95°C
Unknown:
Mass of carbondioxide gas = ?
Solution:
To solve this problem, the ideal gas law will be well suited. The ideal gas law is a fusion of Boyle's law, Charles's law and Avogadro's law.
Mathematically, it is expressed as;
PV = nRT
the unknown here is n which is the number of moles;
P is the pressure, V is the volume, R is the gas constant and T is the temperature.
convert pressure into atm
101.325KPa = 1atm
204 kPa =
= 2atm
Convert temperature to Kelvin; 95 + 273 = 368K
2 x 81.3 = n x 0.082 x 368
n =
= 5.38moles
Since the unknown is mass;
Mass = number of moles x molar mass
Molar mass of carbon dioxide = 12 + 2(16) = 44g/mol
Mass = 5.38 x 44 = 236.9g
Answer:
answer is b
Explanation:
All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor