Which of the following is a physical change

A copper roof changing colors from orange to green

Sawing a piece of wood in half

Rust forming on an iron fence

Burning a piece of wood

In an ice cream maker, why do the ingredients get colder? A) Energy is taken away from the colder ice cream maker. B) The heat moves from the ingredients to the colder ice cream maker.

For a reaction in a voltaic cell, both ΔH° and ΔS° are positive. Given the following equations for standard free energy, ΔG° = ΔH° - TΔS°; ΔG° = - nFE°.

You make the following measurements of an object 42kg and 22m3 what would the objects density be?

1. Calculate the molar enthalpy of solidification (ΔHsolidification) when 10.00kJ of energy are lost as 30.00g of water are frozen at 0ºC. Remember that this value will be negative, because energy is lost when water freezes.

What did the Curies demonstrate by studying pitchblende? Uranium is not the only radioactive element. All elements are potentially radioactive. Radium can cause anemia, bone and tissue damage, and death.

The reaction below has an equilibrium constant kp=2.2*106 at 298 k. 2cof2 (g) ⇌co2 (g) + cf4 (g) calculate kp for the reaction below. cof2 (g) ⇌12co2 (g) + 12cf4 (g)

The electrical conductivities of the following 0.100 M solutions were measured in an apparatus that contained a light bulb as the indicator of conductivity. Rank the solutions in order of decreasing intensity (brightest to dimmest) of the light bulb.

What is the name of a list of elements arranged according to the ease with which they undergo certain chemical reactions?

Why is it harder for the earth to recover from some natural disasters now? A) Human influence may compound the damage. B) The natural disasters have gotten worse. C) This statement is not true.

Heat is most closely related to ___ energy. A. Nuclear B. Electrical C. Thermal