THERMODYNAMICS CALC

Question 1

IF DISTANCE BETWEEN IONS GIVEN, WHAT ARE YOU CALCULATING

Answer 1

electrical energy
E=Kq1q2/r

Question 2

if your finding quantity of heat required used to raise the temp of 1 mol you use

Answer 2

molar heat capacity (change grams to mols of substance.)

Question 3

how will you solve this: calculate ΔU for a system undergoing an endothermic process in which 17kj of heat flows and 3kj of work is done on the system.

Answer 3

Δu= h+w
both positive

Question 4

how: piston is compressed from a volume of 7.90L to 2.15L against a constant pressure of 0.75atm, there is heat given by system of 80kj, what is Δu

Answer 4

1. calculate work w=-pΔV
2. we already have heat given so just plug into formula Δu=q+w

Question 5

if Δt given, with heat given how do you find heat capacity

Answer 5

q=CxΔT
since mass not given, just use this.

Question 6

if heat capacity units are j/molk use

Answer 6

MOLAR heat cap formula

Question 7

asking how much energy given off if grams of n2 given, and Δu given in units kj/mol

Answer 7

convert grams to mols using coefficients of substance divided by its molar mass.
then multiply by the energy.
if energy is not kj/MOL then just convert it to mol by multiplying it with coeficciant…

Question 8

energy given, asking for what mass of NO can be made with Δu given in units kj/mol

Answer 8

convert energy into mols, so take energy divided by Δu and multiply by mol coefficient of substance. then multiply by molar mass go substance to get grams per mol

Question 9

calculating bond energies
calculating enthalpy Δh (and when to calc)

Answer 9

be= reactants-products
Δh= products-reactants (only calculating wehn at constant pressure)

Question 10

calculating work when no Δu or q given
when to use w=-pΔv or w=Δnrt

Answer 10

1. when pressure given and initial/final volumes
2. when reaction is given and temp (in KELVIN)