end-quarter 1 test review. identify which number step is the rate-determining step. step 3
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End-Quarter 1 Test Review
Identify which number step is the rate-determining step.
Step 3
A system absorbs 105 kJ of heat from its surroundings while doing 29 kJ of work on
the surroundings. Calculate ΔE.
76 kJ
2 H2(g) + O2(g) → 2 H2O(g)
If hydrogen is burning at a rate of 0.85 mol/s, what is the rate of consumption of
oxygen?
0.43 mol/s
2 Mg(s) + O2(g) → 2 MgO(s) ΔH = -1204 kJ
How many grams of MgO are produced during an enthalpy change of -96.0 kJ?
6.43 g MgO produced
NH4+(aq) + NO2
-(aq) → N2(g) + H2O(l)
Write the rate law for this reaction.
Rate = k [NH4+] [NO2
−]
CH3OH(l) + O2(g) → CO2(g) + 2 H2O(l) ΔH = -726.5 kJ
What is the enthalpy of the reverse reaction?
+726.5 kJ (reverse rxn, reverse sign)
NH4+(aq) + NO2
-(aq) → N2(g) + H2O(l)
Calculate the value of k. Include appropriate units.
2.7 x 10-4 L/mol·s
CH3OH(l) + O2(g) → CO2(g) + 2 H2O(l) ΔH = -726.5 kJ
If the reaction were written to produce H2O(g) instead of H2O(l), would you expect
the magnitude of ΔH to increase, decrease, or stay the same? Explain.
Decrease (smaller negative); vaporization is an endothermic process, thus adding a
positive value to the current enthalpy
NH4+(aq) + NO2
-(aq) → N2(g) + H2O(l)
What would the rate be when [NH4+] is
4.00 M and [NO2−] is 2.00 M?
0.0022 mol/L·s
When a 9.55-g sample of solid sodium hydroxide dissolves in 100.0 g of water in a coffee-cup calorimeter, the temperature rises from 23.6°C to 47.4°C. Calculate the ΔHsoln in kJ mol-1 for the process. Assume
the specific heat of the solution is 4.18 J g-
1 °C-1.
qcal = 10.9 kJ; ΔHsoln = -45.7 kJ/mol
NH4+(aq) + NO2
-(aq) → N2(g) + H2O(l)
Using experiment #1, how long would it take in minutes until 0.050 M NO2
- remained?86 min
H2(g) + F2(g) → 2 HF(g)ΔH = -537 kJC(s) + 2 F2(g) → CF4(g) ΔH = -680 kJ
2 C(s) + 2 H2(g) → C2H4(g) ΔH = +52.3 kJ
Calculate the ΔH for the reaction of ethylene with F2:
C2H4(g) + 6 F2(g) → 2 CF4(g) + HF(g)
2,390 kJ (2,381.7 kJ)
What happens to the probability of an elementary reactions as its molecularity
increases? Explain.
The probability decreases; less likely to 1) collide with 2) proper orientation and 3)
sufficient energy
Write a balanced thermochemical equation for the formation of NH4NO3(s).
2N2(g) + 2H2(g) + O2(g) → NH4NO3(s) ΔH = -365.6 kJ
How many intermediates are formed in this reaction?
Two
Which color line represents the
highest temperature?
purple
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