Compare: The mass number of C-12 is 12, a value representing the total number of protons and neutrons in the nucleus. Since both protons and neutrons have masses that are just over 1 u, the mass number will typically be very close to the atom’s mass. Add a few atoms each of C-12 and C-13 to the chamber, press Release atoms, and then click on the bars of the graph to reveal a close-up image of each isotope. 1. How does the proton number in each isotope compare?
2. How does the neutron number in each compare?
3. What can you conclude about the role of neutrons in forming new isotopes?

Which of the dna typing techniques do you think you would choose if you had to analyze a dna sample? why?

How many grams of co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next