Please help guys the question is give reasons

a. we have to separate the mixture

b. All impure substances are not harmful.

c. A mixture of iron fillings and sand can be separated by using a magnet

d. A sentences "shake before well use" is written on the bottle of the medicine.

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided

Amatch has about 21 milligrams of red phosphorus coating the tip. how many atoms of phosphorus is this?

Which kind of weather usually forms over the northwest united states in the summer because of maritime polar air masses? 1 )fog 2)dry heat 3) heavy snow 4) heavy rain