[exocytosis646]

The following would represent enthalpy (a change in potential energy)
    a) When the surrounding air gets colder
    b) When water temperature increases in a calorimeter
    c) When an ice cube melts
    d) When a beaker is heated with a Bunsen burner

This question has been very confusing. I believe the answer may be C since an ice cube melting is a spacial change which may be a change in potential energy. And the others represent temperature changes. But an ice cube melting could also represent a temperature change, so im not sure.

[chenbeier]

A,B, C and D have temperature changes. Only C has an additional  change. Which one?

[exocytosis646]

A,B, C and D have temperature changes. Only C has an additional  change. Which one?

A potential energy change. So c is the answer. Thanks

[chenbeier]

The substance change from solid to liquid.

[Borek]

But an ice cube melting could also represent a temperature change

Could it? Does the temperature change during the melting? Why is the enthalpy of fusion called a "latent heat"?

[mjc123]

I don't get the question. All four involve a change in enthalpy. Have you quoted it correctly? Does it ask which involves a change of enthalpy without a change in temperature?