Review Questions: Scientific Method, Atoms, pH 1. Are a compound and a mixture the same thing? Explain. 2. Can you physically separate a mixture? 3. Is Ca2+ a positive or negative ion? How do you know? 4. What is the pH of a neutral substance? (give me a number!) 5. Hydrogen ions are accepted by a ____________ and donated by a _____________. 6. What is the smallest unit of matter? 7. Does a molecule contain atoms? Explain. 8. What is the difference between a covalent bond and an ionic bond? 9. Define a hydrogen bond. 10. In a glass of lemonade, composed of sugar, lemon juice, and water, what could you conclude to be solute, solvent, and solution? 11. What is solubility? Define. 12. Do nonpolar and polar substances dissolve evenly within one another? Explain. 13. What does polar mean? How does this relate to hydrogen bonding? 14. True or False (Explain): An element consists of more than one type of atom. 15. What is the difference between a hypothesis and theory? 16. What is the point of having a constant? 17. If there is more 1 independent variable, is there a way to find out which one affected the dependent variable? 18. What would be a better experiment, one in which there is only 1 independent variable or more than 1 independent variable? 19. What must you do before you form a hypothesis? 20. What is another way of defining “constant”, when it refers to a group that stays constant or unchanging? Why do we need two ways to define a constant?