Answer:
Final temperature = 91.75 °C
Explanation:
Given data:
Mass of water = 45 g
Initial temperature = 12 °C
Energy required = 15 Kj (15000 j)
Final temperature = ?
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Solution:
Q = m.c. ΔT
15000 j = 45 g × 4.18 j/g.°C × (T2 -T1)
15000 j = 45 g × 4.18 j/g.°C × (T2- 12 °C)
15000 j = 188.1 J/°C × (T2- 12 °C)
15000 j / 188.1 J/°C = T2- 12 °C
79.745 °C = T2 - 12 °C
T2 = 79.745 °C + 12 °C
T2 = 91.75 °C
Number of valence electrons
The structures of the isomers and the m/z values of their peaks are not given in the question. The complete question is provided in the attachment
Answer:
Compound 2 (2,5-dimethylhexane) will not have the peaks at 29 and 85 m/z
Explanation:
The fragmentation of molecules by electron ionization of mass spectrometer occurs according to Stevenson's Rule, which states that "The most probable fragmentation is the one that leaves the positive charge on the fragment with the lowest ionization energy". This is much like the Markovnikov's Rule in organic chemistry which has predicted the formation of most stable carbocation and the addition of hydrogen halide to it.
The mass spectra of compound 1 (2,4-dimethylhexane) will contain all the m/z values mentioned in the question. Each peak indicate towards homologous series of fragmentation product of the compound 1. The first peak can be attributed to ethyl carbocation (m/z = 29), with the increase of 14 units the next peak indicates towards propyl carbocation (m/z = 43) and onwards until molecular ion peak of 114 m/z.
Compound 2 (2,5-dimethylhexane) structure shows that the cleavage of C-C bond will not yield a stable ethyl and hexyl carbocation. Hence, no peaks will be observed at 29 and 85 m/z. The absence of these two peaks can be used to distinguish one isomer from the other.
The general formula for a decomposition reaction is shown as option C. AB -> A + B. This type of reaction is simply when a complex compound and or substance is broken down to form its substituent atoms of their respective elements. It is energy releasing as compounds are broken down and is the inverse of a synthesis type of chemical reaction.