Lemon juice reactions

This task is about changes to substances when you add lemon juice to them.
 
A physical change is reversible - it is a temporary change. A chemical change cannot be reversed - it is permanent.
 
Rahera was doing some science in the kitchen. She squeezed the juice from two lemons and divided it equally into two glasses.
She put a teaspoon of baking soda (sodium hydrogen carbonate) into one glass.
She put a teaspoon of salt (sodium chloride) into the other glass.

Question

In the glass with baking soda there was lots of fizzing – in fact the foam spilled over the rim of the glass!
What type of change occurred?
 

    • Physical change

    • Chemical change

Explain your decision.

Question

In the glass with salt, the salt seemed to disappear. 
What type of change occurred?

    • Physical change

    • Chemical change

Explain your decision.