A student puts a tiny piece of metal into a test tube filled with water. She then puts a cap on the test tube. Which change provides evidence that a chemical reaction occurred?

A)the water bubbles
B)the mixture gets heavier
C)the water level increases
D)the metal sinks to the bottom

Name the intersection of plane bpq and plane cpq.

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.)

Sum of brother and sisters age is 26. four times the brothers age is subtracted from three times the sisters age, the difference is 8. what are the ages of the brother and sister?