How do you know/recognize when a double replacement reaction occurs?

What would you do if you told the guy you liked that you liked him

An unknown substance has been shown to have metallic bonds. which of the following is most likely a property of this substance? a. low conductivity b. low boiling point c. high malleability d. high solubility in water

Is the flow of energy during vaporizing more like the flow during melting or during freezing