Which nuclides are used to date the remains of a once-living organism?

(1) C-14 and C-12 (3) I-131 and Xe-131

(2) Co-60 and Co-59 (4) U-238 and Pb-206

Which reactions are endothermic? (Select all that apply.) A. H2 (g) + ½O2 (g) H2O (aq), H = - 57.83 kcal/mole B. ½ N2 (g) + ½O2 (g) NO (g), H = + 21.6 kcal/mole C. ½N2 (g) + O2 (g) + 8.1 kcal NO2 (g) D. ½N2 (g) + 3/2 H2 (g) NH3 (g) + 11.

If the products of a reaction are nacl and h2o what does the law of conservation of mass reveal about the reactants in the reaction?

Al combinarse los átomos de potasio (un metal alcalino) con los átomos de bromo (un no metal del grupo de los halogenos), lo mas probable es que entre ellos se establezca: 1. Enlace covalente. 2. Enlace metálico. 3. Enlace por puentes de hidrógeno.

Why is nitrogen gas very unreactive?

Why is oxygen called a gas. Give two reasons.,

Bases in solution produce what type of ions? a. sulfide ions b. chloride ions c. hydroxide ions d. hydronium ions

How many earth minutes are represented by 0.1 martian sol

Which of the following shows three elements in order of decreasing conductivity? A. Zn, Pd, Ag B. Pd, Ag, Zn C. Ag, Pd, Zn D. Zn, Ag, Pd Which of the following is the name of a metal? A. K B. Potassium chloride C. Potassium D. KCI

Which of the following describes nuclear fission? It requires extremely high temperatures to begin the reaction. It involves the combining of nuclei. It involves bonding electrons. Its chain reactions can be initiated by neutrons.

Which is a quantitative observation A. 15 m long B. red color C. rough texture D. strong odor