What is the mole fraction of oxygen gas in air (see table 5.3 in the textbook) ? express your answer using two significant figures?

How is the half-life of a radioactive material useful for radioactive dating?

Give an example of erosion.

How the elements calcium and chlorine would be named if they formed a chimical compound?

When chemists write out reactions, they often place numbers to the left of a chemical formula. e. g. the first 2 in: 2H+O-->H2O.

If the patient has to be administered a dosage of 2 tablets every 6 hours for 7 days, what is the number of tablets required for the prescribed dosage?

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