Answer:
First and last sentence .♀️
Explanation:
An important thing to keep in mind about the Reading Comprehension section of the GRE as we use PowerPrep online to study is that it is just that—reading comprehension. In other words, as difficult as it may seem, and it can be pretty tricky, the test makers will always give us all the information we need in the passage to answer the question.
The number of each type of atom on the right side of the equation
that is
Pb(No3)2(aq) + 2 NaCl(aq) = PbCl2(s) +2NaNo3(aq)
are 1 atom of Pb
2 atoms of N
6 atoms of O
2 atoms of Na
2 atoms of Cl
Explanation
In Pb(NO3)2 there is 1 x1=1 atoms of Pb, 1x2 =2 atoms of N and 3x2 =6 atoms of O
In NaCl there is 2 x1= 2 atoms of Na and 2 x1=2 atoms of Cl
Enthalpy of formation is defined as the heat change that is needed for formation of one mole of substance from its constituent elements in pure state.
In present case, Heat of formation of one mole of C2H6 at <span>101.3 kpa and 298 k is -84 kJ/mol. Negative sign indicates that, heat is evolved from the system.
Thus, for two mole of ethane, heat of formation will be 2 X (-84) = -168 kJ/mol.
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Answer:
an aqueous species is the answer