How long would it take for the amount of U-235 to reach 1/8 of its initial amount? t= million years

Which of the following are correct values for the ideal gas laws constant r

In an exothermic reaction, energy may be released to the surroundings in the form of question 4 options: heat light thermal all of the above

Why must humans find substitutes for many minerals found on earth? (a) form at an extremely slow rate (b) controlled by other countries (c) too deep in the earth to collect