Chem Quiz

1. Classify the following as either a chemical or physical change. 

Burning wood: chemical 

Crushing a rock: physical

Dissolving sugar in water: physical

The rusting of iron: chemical

 I got all the above correct

2. Classify the following as to whether or not they are pure substances or mixtures. 

milk: pure mixture 

table salt: mixture

sugar: pure

steel: pure mixture

I chose pure for milk because it hasn't been tampered with, but it is indeed a mixture. Same with steel, I put pure but it is a combination of iron and carbon

3. A cup of black coffee is considered to be __?__ and a/an __?__ substance. 

(a) homogeneous�..pure

(b) homogeneous�..impure

(c) non-homogeneous�pure

(d) non-homogeneous�impure 

I chose homogenous because there is no milk or any other substance in it, but coffee itself is not pure.

4. The boiling of water is considered to be a __?__ change and the temperature at which water boils is considered to be a __?__ property. 

(a) chemical�..chemical

(b) chemical�..physical

(c) physical�..chemical

(d) physical�..physical

I chose physical and physical because there is no chemical change that is occurring. The water is still there and hasn't changed.