What is the main function of the immune system?

To provide energy for the body

To circulate blood and nutrients

To defend against pathogens

All of the above

Who performed the oil-drop experiment?

A chemist dilutes 77.9 ml of 5.50 M sodium chloride to make a 1.93 M solution. What is the final volume of the diluted solution (in ml)

Which of there is an indication that a chemical reaction has occurred? a. freezing of substance b. a change in color of a substance c. melting of a substance d. boiling of a substance

How many neutrons does element ex have if it's atomic number is 58 and it's mass numbers 156

Consider the following reaction: Li3N (s) + 3H2O (l) → NH3 (g) + 3LiOH (l) If you need to make 24 g LiOH, how many grams of Li3N must you react with excess water?

Which would not be classified as a pure substance?

According to Boyle's law, how would you reduce the volume of a gas? a. by decreasing its pressure b. by increasing its temperature c. by decreasing its temperature d. by increasing its pressure

To what chemical reaction class does this reaction belong? 2 mg (s) + o2 (g) 2 mgo (s)

Which best illustrates how particle arrangement changes when solids change into liquids

Express in scientific notation (6.0x10^4) (3.1x10^-1)