Which is a property of covalent compounds? They ionize in solution. They tend to be very hard. They have a low boiling point. They have a high melting point.

Atrain travels 74 kilometers in 3 hours, and then 81 kilometers in 5 hours. what is its average speed?

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.)

Rank the four gases (air, exhaled air, gas produced from from decomposition of h2o2, gas from decomposition of nahco3) in order of increasing concentration of co2