What condition must be true for a chemical reaction to be spontaneous?

Using the following S^o values 

H₂(g),      S^o = 130.58 J·mol^-1·K^-1

C₂H₄(g),  S^o = 219.4 J·mol^-1·K^-1

C₂H₆(g),  S^o = 229.5 J·mol^-1·K^-1

calculate ΔS^o in J mol^-1 K^-1 for the reaction below.

C₂H₄(g) + H₂(g) → C₂H₆(g)

Enter your answer in the box.  Do not enter units.

Conclusion

You should finish your report with a short statement commenting on what was achieved, and what the final numerical result/s were. Think of it as a spoiler for your whole lab report! Your conclusion should answer all parts of your aim.

For example:

If the aim is: Determine the concentration of Vitamin C in a fruit juice via a redox titration against N-bromosuccinimide.

The conclusion might be: Berri orange juice (2000 μL aliquots, in triplicate) was titrated against a 0.104 M solution of N-bromosuccinimide. The concentration of Vitamin C in the fruit juice was determined to be 55.0 mg/L.

Interpreting atomic-scale depictions

Which of the following images best represents the structure of NaCl after dissolution?

Note that atomic radius has not been taken into account for the following images.

Mass calculation

Assuming you had 0.013 moles of copper chloride, what amount of 4 M NaOH would be the minimum volume you could use in Section 2.1 of Exercise 3?

State your answer in millilitres but remember SI units are litres. Report to one decimal place. Do not include units with your answer.

The Analytical Balance Room

• The room in the centre of the 1st Year laboratories houses our analytical balances.
• Analytical balances are highly sensitive and can measure masses to the microgram.
• To maintain their accuracy, the balances are serviced and calibrated annually.

Figure 1: Analytical balance

To ensure the analytical balances are kept in working order we must:

• Prevent solids or liquids from getting under the balance pan (to avoid corrosion and mechanical interference). Contamination under the pan can cause significant damage, costing thousands of dollars in repairs!!
• Ensure the electronics remain in good condition by never operating an analytical balance while wearing gloves.

From the list below, select the items that should not be worn or taken into the analytical balance room.