Plz answer thx

how many moles are in 2.5 x 10^18 grams of water?

Which of the following is always a reactant in a combustion reaction? oxygen nitrogen hydrogen carbon

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)

Describe the forces both attractive and repulsive that occur as two atoms move closer together.