Answer:
I think A.
Explanation:I say A because of the substance melting the quicking does have the highest melting point because its the highest.
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
There are three types of tectonic plate boundary. These are divergent, convergent and transform plate boundaries. The divergent boundary is a fault where two plate move away from each other. Convergent is when two separate plates push each other. Lastly, transform plate boundary is when two plates slide past each other.
M P₂O₅ = 31g×2 + 16g×5 = 142g/mol
1 mole of P₂O₅ contains 5 moles of atoms
5 moles of atoms = 30,01×10²³ a.
142g ----------- 30,01×10²³ a.
0,69g ---------- X
X = (0,69×30,01×10²³)/142
X = 0,14626×10²³ = 1,4626×10²² atoms
:)
25*5= 225 and 7hs hsueuxn udneicj
