Select all of the following that are correct about mechanical waves. They can be longitudinal.
They can propagate in a vacuum.
They can be transverse.
They can propagate in a physical medium.
They transfer energy from particle to particle.

What type of reaction is shown below? check all that apply. 2h2o2 → 2h2o + o2 synthesis decomposition combustion

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.)

Ahelium balloon contains 16.9 l of helium at stp. how many atoms of helium are in the balloon