How many moles are present in 9.15 grams of h2o

Which metal exist in liquid state and can be cut with knife ?

Amixture that has two or more substances that are spread out evenly is called a. compound b. heterogeneous c. substance d. homogeneous

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?