If we start with 48 g of a radioactive substance with a 2 hour 12 life, how much is left after two half-lives? four half-lives?

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Which of the following is an example of motion in two dimensions?

Choose all the answers that apply. our solar system: is in a spiral galaxy no longer includes pluto is made mostly of empty space is in the andromeda galaxy is the only known system that supports life