The radioactive isotope tritium decays with a first-order rate constant k of 0.056 year-1. what fraction of the tritium initially in a sample is still present 30 years later?

Which of the following is an example of energy causing motion? A. bowling ball on a ball stand B. boy holding a bowling ball C. rolling ball scattering the bowling pins D. Bowling pins scattered on the ground

What is the angle between two of the nitrogen-hydrogen bonds in the ammonium (nh4) ion?

Which compound will form by the joining of ca and br? view the periodic table a. cabr2 b. ca2br c. ca2br2 d. cabra. cabr2?

two objects of different masses are sitting on a different balance scales. object A has a greater mass than object B how will the weights of the objects compare to each other?

Different elements emit different emission spectra when they are excited because each type of element has a unique energy level systems. Each element has a different set of emission colors because they have:

In the fourth century bc Greek scholars rejected Democritus ideas about the atom. This rejection was mostly based on?

An element X has two isotopes. X-15 has 7 protons and 8 neutrons. Determine the atomic number and mass number of the second isotope, which has 10 neutrons in its nucleus. a. atomic number = 8; mass number = 9 b. atomic number = 8; mass number = 17 c.

Which statement best describes the direction of heat flow by conduction between two samples of the same material? 1. Heat flows from faster molecules to slower molecules when they are near. 2.

Delta H equals 98.8 KJ, and Delta S equals 141.5 J/K. Is this reaction spontaneous or nonspontaneous at high and low pressure

Secondary consumers are eaten by?