If you started with 1000 units of a radioactive element that has a half-life of 2,500 years, how many half-lives will the material have gone through in 7500 years? (Show work and explain answer).

Why is a drip irrigation system more sustainable than traditional spraying methods of irrigating crops? A. It leads to reduced river flow. B. It causes the water table to drop. C. It reduces pollution from runoff. D. It decreases water quality.

When heated to 700-800 °c, diamonds, which are pure carbon, are oxidized by atmospheric oxygen. (they burn!) write the balanced equation for this reaction?

Where is energy stored in electromagnetic waves? a. in the wave's moving atoms b. in the oscillating electric and magnetic fields c. in the electromagnetic force d. in the wave's directional vector

Using the drop-down menu, order the steps in the dissolving process. the solvent molecules surround the solute molecules or ions. the solute molecules are carried into the solution. the solute is mixed with the solvent.

The equilibrium concentrations were found to be [h2o]=0.250 m, [h2]=0.370 m, and [o2]=0.750 m. what is the equilibrium constant for this reaction

The volume of 1 mole of o2 gas at T=273k P=1atm is? A 6.02 x 10^-23 ml B 760 L C 22.4 L D 2.24 L E 224 L

There are two stable isotopes of bromine. Their masses are 78.9183 and 80.9163 amu. If the average atomic mass of bromine is 79.9091 amu, what is the natural abundance of the heavier isotope? percent abundance of 81Br __%

If 1.00 mol of argon is placed in a 0.500-L container at 20.0 ∘C, what is the difference between the ideal pressure (as predicted by the ideal gas law) and the real pressure (as predicted by the van der Waals equation) ? For argon, a=1.

Which of these is a covalent compound? 1. AICI3 2. CO 3. MgO 4. LiCI

What is a protein used for