What is the approximate weight of a 20-kg cannonball on earth

Radiation can cause long-term problems once it enters the environment.

2) suppose you discovered a new element with 120 protons and 2 electrons in its outermost energy level (valence shell). a. in which group does this new element belong? b.

a ballon filled with helium contains 85L and 1.2 atm. the pressure is reduced to 0.22 atm at constant temperature. what is the new volume? given info: equation. work: answer

Isaac the robot needs to travel from his charging station to school. Isaac travels 5 km south, 3 km west, 2 km north and 3 km east. What distance did Isaac travel

A cup of coffee is so hot that it cannot be drunk. As a result, an ice cube is put into the coffee. What direction is the energy moving? When would the energy flow stop?

How many grams of NH4Cl will be needed to make a 1L solution with a concentration of 4.5M?

What is the oxidation number change for the manganese atom in the following unbalanced reduction half reaction: MnO4 - (aq) + H + (aq) → Mn2 + (aq) + H2O (l) ?

What is the empirical formula for butane, C4H10

Scientist are always learning new things. which of the following shows how scientist use observations to gain new understanding about the world? A. scientists have discovered new planets orbiting a star by detecting a wobble in the star's motions. B.

A chemical reaction, where more energy is released than is needed to get the reaction started, is called? A) A really amazing reaction B) Endothermic C) Exothermic D) Non-reactive