By what are isotopes identified? A. mass numbers

B. atomic masses

C. atomic mass units

D. average atomic masses

What is the atomic number of the element in Group 4A, and Period 5? a. 68 b. 131 c. 222 d. 462

The boundary where two air masses meet is called a

An aqueous magnesium chloride solution is made by dissolving 6.92 6.92 moles of MgCl 2 MgCl2 in sufficient water so that the final volume of the solution is 2.00 L 2.00 L. Calculate the molarity of the MgCl 2 MgCl2 solution.

An athlete is running a 5-km race at am average speed of km/h. She has to stop to tie her shoe. After tying her shoe, she continues running at 8km/h. Why would her average speed for the entire race be less than 8km/h

3.011 x 10^23 atoms F in grams

When 4.70 g of a nonelectrolyte solute is dissolved in water to make 935 mL of solution at 28 °C, the solution exerts an osmotic pressure of 943 torr.

What is the half-life of a radioisotope if a 40 g sample becomes 10 g after 20 minutes?

What fact shows that baking a chocolate chip cookie is a chemical reaction? The final product tastes and looks different from the original ingredients. All of the ingredients are mixed up in the cookie.

What specifically does STR measure? A) STR length B) the number of repeating units C) distance traveled on electrophoresis gel D) the difference between the number of repeating units between two STRs

The reaction A (g) ⇌ 2 B (g) A (g) ⇌ 2 B (g) has an equilibrium constant of K = 0.010 K = 0.010. What is the equilibrium constant for the reaction B (g) ⇌ 1 2 A (g) ?