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Across 5. a _____ ______ is a unit of length equal to the distance light travels in one year. This is a distance of about 9.5 trillion kilometers per year (Fact 136) 7. _________ are organic compounds made of living things (Fact 301) 12. One astronomical unit is equal to the average distance between the Earth and the ______; it is a distance of approximately 150, 000,000 kilometers (Fact 133) 13. a _______ ______ is a force of attraction that holds two atoms together as a result of the rearrangement of electrons between them (Fact 276) 14. The _____ ______ ranges from 0 (very acidic) to 14 (very basic) (Fact 293) 15. a _________ force causes objects to move in a circle (Fact 119) 18. The largest mountain in the solar system, _______ _______ is found on Mars. It is nearly 3x as tall as Mount Everest (Fact 150) 23. the _______ _______ is used to measure distances in between the Earth and the sun (Fact 132) 24. _______ is a force that is exerted when matter is pushed or squeezed (Fact 97) 25. Any substance that has a pH of 7 is _______ meaning that it is neither acidic or basic (Fact 294) 27. the _______ ______ of an element is the weighted average of all of the isotopes of that element (Fact 253) 29. a ______tastes bitter, feels slippery, conducts electricity, and has a pH of greater than 7 (Fact 290) 30. Hot stars are _______, cold stars are red (Fact 178) 31. protons are positively charged, _______ have no charge, and electrons have a negative charge (Fact 242) 34. an ________ is a substance that changes color in the presence of an acid or a base (Fact 291) 35. A chemical reaction in which energy is released is called _________ (Fact 288) 37. ________ is the tendency of all objects to resist a change in motion (Fact 123) 38. All of the inner planets are small and _______ and have rocky surfaces (Fact 140)

Down 1. the magnitude of air resistance acting on an object depends on the ______, shape, and speed of the object (Fact 115) 2. acids turn blue ____ ____ red and bases turn red ___ ____ blue(Facts 292 and 293) 3. _________ is a force that is exerted when matter is pulled or stretched (Fact 96) 4. proton 6. the formula to calculate _____ is speed x time (Fact 78) 8. ______ _____ is a force that opposes the motion of objects through air (Fact 114) 9. density, mass, volume, solubility, malleability and ductility are examples of ______ properties of matter (Fact 205) 10. _______ is a substance's resistance to flowing. It depends on the size and shape of the particles and the attractions between them (Fact 222) 11. All forces have ___________ and magnitude(size) (Fact 88) 16. The four inner or _______ planets are Mercury, Venus, Earth and Mars (Fact 138) 17. _______ _______ is the force acting on the surface of a liquid that causes the liquid that causes the liquid to form spherical drops (Fact 211) 19. _______, reactivity with oxygen,reactivity with an acid, reactivity with a base, reactivity with oxygen are examples of chemical properties ( 20. A chemical reaction in which energy is being absorbed is called _______ (Fact 287) 21. elements in the same _______ or family on the Periodic Table have similar properties (Fact 271) 22. _______ are atoms from a particular element that have the same number of protons but a different number of neutrons (Fact 252) 26. ___________ is the fourth planet from the sun, is known as the Red Planet, has a lot of volcanic activity, and has two moons (Fact 149) 28. _______ is a force that opposes the motion between two surfaces (Fact 100) 32. the formula to calculate _______ is distance divided by speed (Fact 79) 33. ________ is the second planet from the sun and is the planet most similar to Earth in size, shape and density (Fact 142) 36. An ______ reacts with metals, tastes sour, conducts electricity , can destroy body tissue and has a pH of less than 7 (Fact 289)