Which is a pure substance?

air

nitrogen

apple juice

tap water

As a sample of the radioactive isotope 131I decays, its half-life (1) decreases (2) increases (3) remains the same

An excess of Ba (No3) 2 reacts with 250ml of H2SO4 solution to give 0.55g of BaSo4. determine The concentration in moles per litre of the Ba (No3) 2 solution?

What is the mole fraction of acetic acid in a solution containing 2 moles of vinegar and 3 moles of water? A. 2 B. 3 C. 0.4 D. 0.5

Which of the following statements are true with respect to enzyme activity? Check all that apply. View Available Hint (s) Check all that apply. Enzymes speed up the reaction rate.

Convert to standard notation. 7.77 x 10-4

A saline solution contains 1.6 % NaCl by mass. How much NaCl is present in 57.2 g of this solution?

During a laboratory experiment you discover that an enzyme-catalyzed reaction has a delta G of - 20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the delta G for the new reaction

What is the molarity of a hydrochloric acid solution prepared by diluting 200.0 ml of 0.500m hcl to a total volume of 1.00 l?

How does a metallic bond differ from an ionic bond

Give two examples of chemical energy being transformed into electrical energy