(NEED HELP ASAP) Which statement best describes a key difference between a solar and lunar eclipse? A.
During a lunar eclipse, the moon passes through Earth’s shadow; during a solar eclipse, the moon's shadow moves across Earth.

B.
During a lunar eclipse, the moon’s shadow falls on Earth’s surface; during a solar eclipse, the moon passes through Earth’s shadow.

C.
Solar eclipses happen once every ten years while lunar eclipses occur with every new moon.

D.
Solar eclipses occur with every new moon while lunar eclipses happen every five to six years.

An exothermic reaction is conducted in an insulated calorimeter filled with water. the calorimeter is then sealed so that there is no heat exchanged between the contents of the container and the surrounding air. which of the following statements is true about the reaction?

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.

What is the solubility of substance?