Describe two physical properties that depend upon a change of state in the material.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

When a device is used in a circuit in which the voltage is 81 v the current flowing through the device is 3 a what is the resistance of the device

Pls ill give u brainliest which of the following is true about science? 1. political conditions are unable to influence it. 2. economic concerns may prevent it from solving problems.