Question

what do these two changes have in common? your breath becoming visible on a cold day making paper from wood select all that apply. both are changes of state. both are caused by heating. both conserve mass. both are caused by cooling.

Explanation:

• Breath becoming visible on a cold day: This is a physical change (condensation of water vapor in breath). In physical changes, mass is conserved. It is caused by cooling (the cold air cools the water vapor in the breath, causing it to condense).
• Making paper from wood: This is a physical change (processing wood fibers). Mass is conserved as the mass of the wood is transformed into the mass of the paper (neglecting any losses like during drying, but in a closed - system - like accounting, mass is conserved). It is not a change of state (wood is a solid, paper is a solid - like material made from wood fibers). It is not caused by heating in the sense of a phase - change - heating (it involves mechanical and chemical - like pulping processes, but not a simple heating - induced phase change). However, if we consider the general conservation of mass principle (applicable to both physical and chemical changes in an isolated system), and the fact that the breath - visibility is a physical (state - change - related, condensation) and the paper - making is a physical (re - arrangement of wood fibers) change where mass is conserved.

Answer:

Both conserve mass.