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Determine the number o moles of ions/atoms/particle in the following: 2.50 miles of k2s (let me know how to do)

Lewis structure and molecular geometry for nh2cl

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.