67. What is an atomic nucleus? (1 point) the outer part of an atom in which electrons move
the outer part of an atom in which neutrons move
the central part of an atom, composed of protons and neutrons
the central part of an atom, composed of protons and electrons

6. what does the symbol ah stand for? o one calorie given off by a reaction the specific heat of a substance the heat capacity of a substance the heat of reaction for a chemical reaction

What three things determine the shape and size of a puddle when water is poured out onto a surface

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.