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
Glass doesn't contain planes of atoms that can slip past each other, so there is no way to relieve stress. It has many microscopic cracks that act as seeds for fracture. It’s molecular structure is composed of tetrahedral crystals so it ruptured easily under stress
Answer:
6,2g of CO₂
Explanation:
Based on the reactions:
Li₂O(s) + H₂O(g) → 2LiOH(s)
LiOH(s) + CO₂(g) → LiHCO₃(s)
2,6g of Li₂O and 1,3g of H₂O are:
2,6g × ( 1mol / 29,88g) = 0,087 moles
1.3g × ( 1mol / 18,01g) = 0,072 moles
That means limiting reactant is H₂O. The moles produced of LiOH are:
0,072 moles of H₂O × ( 2mol LiOH / 1mol H₂O) =<em> 0,14 moles of LiOH</em>
Thus, the maximum CO₂ that can react are 0,14 moles of CO₂, in grams
0,14 moles CO₂ × (44,01g / 1mol) = <em>6,2g of CO₂</em>
I hope it helps!
Answer:
Mass = 88.12 g
Explanation:
Given data:
Mass of iron oxide = 126 g
Mass of iron formed = ?
Solution:
Chemical equation:
Fe₂O₃ + 3CO → 2Fe + 3CO₂
Number of moles of iron oxide:
Number of moles = mass/molar mass
Number of moles = 126 g/ 159.69 g/mol
Number of moles = 0.789 mol
Now we will compare the moles of iron with iron oxide.
Fe₂O₃ : Fe
1 : 2
0.789 : 2/1×0.789 = 1.578 mol
Mass of iron:
Mass = number of moles ×molar mass
Mass = 1.578 mol × 55.84 g/mol
Mass = 88.12 g
