Chemistry Quiz

Which of the following solutes would dissolve in water?

• NaBr

• NH3

• C3H8

• SCl2

Which of the following solutes would dissolve in Benzene (C6H6)?

• KCl

• C2H6

• NaBr

• Br2

Determine the ΔHrxn. 2SO2 (g) + O2 (g) → 2SO3 (g)

• 98.9 kJ/mol

• -98.9 kJ/mol

• -197.8 kJ/mol

• 197.8 kJ/mol

The enthalpy of the combustion of butane gas (C4H10) is -2878 kJ/mol. Which statement is incorrect?

• The combustion of butane is an exothermic process

• Butane releases heat as it burns

• The energy of the products is higher than the energy of the reactants

• Heat transfers from the system to the surroundings

The entropy of the reaction H2(g) + Br2 (g) → 2HBr (g) is:

• Increasing

• Decreasing

• Staying the same

• Not present

If the ΔH is ___ and the ΔS is ___, then a reaction will always be spontaneous.

• -,-

• +,+

• +,-

• -,+

When ΔG is +, a reaction will be

• Spontaneous

• Nonspontaneous

A piece of steel wool is heated in air (~20% oxygen) burns slowly, but when heated in pure oxygen, rapidly combusts producing a dazzling shower of sparks. This shows the effect of ___ on rates.

• Temperature

• Concentration

• Nature of reactants

• Surface Area

Storing foods and milk in a refrigerator helps to slow down reactions that ordinarily result in spoiling and souring. This shows the effect of ___ on rates.

• Temperature

• Concentration

• Nature of reactants

• Surface Area

Which of the following is NOT true for a completion reaction?

• Forms a gas or a precipitate

• Can reach equilibrium

• Represented by a →

• Reaction eventually stops