Question

a solution of salt water was placed in the evaporating dish. the burner flame was lit and soon caused the water to evaporate out of the dish. a white crystal was left behind in the dish.

1. when the substance was placed initially in the evaporating dish, certain what type of matter was it and why.
2. after the water evaporated away and left a white crystal solid, identify the solid and explain which type of matter it can be classified as.

Explanation:

Step1: Analyze the evaporation process

When salt - water is heated in an evaporating dish, water evaporates due to heat from the Bunsen burner. This is a physical change.

Step2: Identify the remaining solid

The white crystal left behind is salt (sodium chloride, NaCl). Salt is a compound as it is composed of two different elements (sodium and chlorine) chemically bonded together.

Answer:

The white crystal solid is salt (sodium chloride). It is a compound.