Uranium-235 has a half-life of 713 million years, while carbon-14 has a half-life of about 5,730 years. Which isotope would be more useful for dating a fossil from Precambrian time?

In a water molecule, two hydrogen atoms bind to one oxygen atom. How many lone pairs of electrons will be shown around each hydrogen atom in the Lewis structure of water?

What did J. J. Thomson's cathode-ray tube experiment show? a. Atoms are small individual spheres. b. Electrons are in a cloud surrounding positively charged particles. c. Matter can be neither created nor destroyed. d.

Which chemical equation is correctly balanced? (1) H2 (g) + O2 (g) = > H2O (g) (2) N2 (g) + H2 (g) = >NH3 (g) (3) 2NaCl (s) = >Na (s) + Cl2 (g) (4) 2KCl (s) = > 2K (s) + Cl2 (g)

Which is true of a tea kettle and a penny with equal tempatures? A. They have the same thermal energy B. The penny has more thermal energy C. The tea kettle has more thermal energy

What is a special type of mixture where one substance is dissolved in another

How can you tell if a chemical reaction has occurred?

An engineering team is conducting a trial launch of a new rocket. Which part of the engineering process is the team in?

What is a physical property of copper

Which of the following occurs when the ocean's salinity increases? a. density increases. b. density decreases. c. temperature increases. d. temperature decreases.

What name is given to the bond between water molecules?