A calorimeter contains 251 g of water at 24.3 C. The temperature of the water decreases to 18.5 C when 12.5 g of potassium nitrate is dissolved in water. Is dissolving potassium nitrate in water endothermic or exothermic

Asample contains 16.75 g of the radioisotope u-236 and 50.25 g of its daughter isotope, th-232. how long did it take for decay to take place if one half-life of u-236 is 23 million years? 46 million years 69 million years 92 million years 115 million years

What happened in 2012 and how does it illustrate the importance of understanding the sun and how it works?

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line