a radioactive substance has a half-life of 10 years. if you start with 30 grams of the substance, how much will remain after 30 years.

What is the energy of a photon of infrared radiation with a frequency of 2.53 * 1012 Hz? Planck's constant is 6.63 * 10-34 J • s. A. 1.68 * 1023 J B. 1.68 * 1047 J C. 1.68 * 10-21 J D. 1.68 * 10-45 J

What are the tree sub types of convegent plate boundaries

Identify the isotope where A equals 49 and Z equals 22. A) Indium-22 B) Indium-27 C) Indium-49 D) Titanium-22 E) Titanium-27 F) Titanium-49 G) None of the choices are correct.

T's a hot sunny day and you decide to go for a drive. When you open your car door, it's a lot hotter inside than outside. Why is that?

What are three conditions that can cause chemical reactions to occur?

The temperature of 15 grams of water increases by 3.0 degress. how much heat was absorbed by water?

What are the four types of stoichiometry problems?

100 ml oxygen at 1.75 atm and 200ml nitrogen at 0.6 atm are passed to a 500 ml vessel. Calculate the total pressure of the mixture in the vessel at same temperature

Which is the best metal to use in an alloy to increase its electrical conductivity

Ice does not need to melt into liquid water before it can return to the atmosphere as water vapor. a. True b. False