Answer:
1.88 × 10²⁴ atoms
Explanation:
Step 1: Given data
Mass of sulfur: 100 g
Step 2: Calculate the moles corresponding to 100 g of sulfur
The molar mass of sulfur is 32.07 g/mol. The moles corresponding to 100 g of sulfur are:
100 g × (1 mol/32.07 g) = 3.12 mol
Step 3: Calculate the number of atoms in 3.12 moles of sulfur
We will use Avogadro's number: there are 6.02 × 10²³ atoms of sulfur in 1 mole of sulfur.
3.12 mol × (6.02 × 10²³ atoms/1 mol) = 1.88 × 10²⁴ atoms
The balanced reaction equation for the reaction between CH₃OH and O₂ is
2CH₃OH(l) + 3O₂(g) → 2CO₂(g) + 4H₂O(l)
Initial moles 12 24
Reacted moles 12 18
Final moles - 6 12 24
The stoichiometric ratio between CH₃OH and O₂ is 2 : 3
Hence,
reacted moles of O₂ = reacted moles of CH₃OH x (3/2)
= 12 mol x 3 / 2
= 18 mol
All of CH₃OH moles react with O₂.
Hence, the limiting agent is CH₃OH.
Excess reagent is O₂.
Amount of moles of excess reagent left = 24 - 18 mol = 6 mol
Answer:
CuCl2 + 2NaNO3 - > Cu(NO3)2 + 2NaCl
a) The reaction is exothermic since the overall enthalpy change is negative. this means that the system has lost energy to the environment, namely, the apparatus and due to drought.
b) We first calculate the number of moles in 3.55 grams of magnesium.
number of moles= mass/ atomic mass
=3.55/24
=0.1479 moles(to 4sf)
now, if 2 moles of magnesium give -1204kJ
How much energy is given by 0.1479 moles
= (0.1479×-1204kJ)
=-89.0358kJ (don't forget the negative sign)
c) two molesof MgO produces -1204kJ of energy
then -234kJ will be produced by
=(-234kJ×2moles)/1204kJ
=0.3887moles
one mole of MgO weighs 24+16=40
therefore the mass produced is 0.3887moles×40=15.548grams
(d) we first find the number of moles of MgO in 40.3 grams
number of moles=mass/RFM
=40.3g/40= 1.0075moles
if 2 moles of MgO give 1204 kJ then decomposing 1.0075 moles requires
(1.0075 moles×1204kJ)/2=606.515kJ
