How many of the following are pure compounds? sodium, sugar, oxygen, air, iron

How many of the following are pure compounds? sodium, sugar, oxygen, air, iron

Answer :-

Sodium is a element 

Sugar is a compound 

Oxygen is also a element 

Air is a mixture 

Iron is element 

so answer of this problem is sugar 

Which of the following processes require(s) chemical methods? 
a)Separating a homogeneous mixture into pure substances.
b)Separating a heterogeneous mixture into pure substances. 
c)Distilling a saltwater mixture. 
d)Breaking a compound into its constituent elements. 
At least two of the above (a-d) require chemical methods

Answer :-

a)Separating a homogeneous mixture into pure substances. Its can involve both physical and chemical method for the separation

b)Separating a heterogeneous mixture into pure substances. IT involve physical method only 

c)Distilling a saltwater mixture it is a physical method

d)Breaking a compound into its constituent elements.  this is a chemical reaction

so Answer is a and d

Which is an example of a homogeneous mixture? 
a)vodka
b)oily water 
c)soil (dust) 
d)sodium chloride aluminum


in this problem Vodka is homogeneous mixture because  in out of four option,only vodka has a uniform composition throughout