It is an alloy <span>made of copper, magnesium, manganese, and aluminum.</span>
The conditions given are stp or standard temperature and pressure. This would be considered the substance's standard state.
Answer:
239.0 g/mol
Explanation:
The molar mass of a compound is the sum of all the molar masses of all the individual elements present in the compound.
The molar mass of Ca(ClO4)2 can calculated as follows:
= 40 + 2[ 35.5 + (16x4)]
40 + 2[ 35.5 + 64]
40 + 2[99.5]
40 + 199
239g/mol
Answer:
ΔH = - 254 kJ
Explanation:
The final equation for the enthalpy of formation we want to calculate is:
2 CO₂ (g) + 6 H₂(g) -------------- CH₃OCH₃ (l) ΔH = ?
Notice that if we take the 2 times the first reaction and add the second , by Hess's law we will add the enthalpy changes to obtain our desired ΔH .
( CO₂(g) + 3H₂(g) CH₃OH (l) + H₂O(l); ΔH = -131.kJ) x 2
2CO₂(g) + 6H₂(g) --------- 2CH₃OH (l) + 2 H₂O(l); ΔH = -262.kJ
2CH₃OH (l) --------- CH₃OCH₃(g) + H₂O (l); ΔH = 8.kJ
_____________________________________________________
2CO₂(g) + 6H₂(g) ----------- CH₃OCH₃(g) + 3H₂O (l); ΔH = -254 kJ
