Properties of Water Practice Quiz

1. What two elements make up water? Hydrogen (H) & Oxygen (O) 2. Write the chemical formula for water. H2O 3. Is water an element, compound, or mixture? Compound

4. Define the term compound. A substance with two or more elements chemically combined in definite proportions. 5. What kind of chemical bond exists between a hydrogen and oxygen atom in a water molecule? A covalent bond

6. Draw a model of a water molecule. (+) (-) The parentheses mean ‘partial.’ 7. Draw partial (+) and partial (-) charges on the water molecule you drew above. δ + This symbol also means partial →

8. Which of the following molecules are polar? (-) (+) (-) (-) (-) (+) (+) (-) (-) (+) (+) water carbon dioxide ammonia (+) (+) (-) (+) (-) (-) (-) (+) (+) (+) (+) Hydrogen chloride formaldehyde methane

9. Draw two water molecules and a hydrogen bond. (+) (-) 1 The use of dashed lines show that hydrogen bonds are relatively weak. Hydrogen bond 4 3 2 10. How many hydrogen bonds can a water molecule form with other water molecules? Four

11. What term describes the attraction between molecules of the same substance? Cohesion B A No 12. Without a hydrogen bond, when molecule A moves to the right, will it be able to drag molecule B along with it?

Yes 13. With a hydrogen bond between them, will molecule A be able to drag molecule B along with it? A B Yes

14. What are some examples of water cohesion? Surface tension Drops on a penny Insect trapped in water A proboscis keeps this bee at a safe distance

15. What are some examples where surface tension breaks down? “Scaring” pepper Bread clip motor boat

16. What term describes the attraction between molecules of different substances? Adhesion (+) (-) glass Water drop on glass slide

17. What will happen when a charged rod or balloon is brought up close to a stream of water? The water will be attracted toward the rod

A meniscus that water forms in a glass tube. 18. What are some examples of water adhesion? A meniscus that water forms in a glass tube. Capillary action

Duck feathers repel water 19. What are some examples of anti-adhesion? Scotchgard ® carpet Water on wax paper Wax-layer on leaves Duck feathers repel water

Nature has never made this type of material. New: Researchers have made an omniphobic material that repels both water and oil. Nature has never made this type of material.

Heat Capacity 20. What is the term which describes the amount of heat energy needed to increase a substance’s temperature? Heat Capacity

Water 21. Which substance in the chart is able to absorb the most heat for a given change in temperature? Water

Air 22. Which substance in the chart is able to absorb the least amount of heat for a given change in temperature? Air

23. What example in the Properties of Water lab demonstrated a low heat capacity for air and a high heat capacity for water? Air-filled balloon Water-filled balloon

25. What are some examples of mixtures? 24. What is a mixture? A substance made up of elements or compounds that are combined but not chemically bonded together. 25. What are some examples of mixtures? copper zinc water sugar corn syrup CO2 caramel caffeine citric acid Beef Onion Tomato Lettuce Cheese Ketchup Mustard bread

what does the dissolving what is being dissolved 26. What are two kinds of mixtures made with water? Solutions and suspensions 27. Compare solvent, solute, and solution. water solvent what does the dissolving Sugar water solution Sugar cubes solute what is being dissolved

29. Which substance(s) below dissolve in water? 28. Define a solution? A mixture in which the molecules of the mixed substances are evenly spread out. 29. Which substance(s) below dissolve in water? Magnesium sulfate polar iodine Non polar salt polar Non polar paraffin wax oil Non polar

31. What some examples of suspensions? 30. What is a suspension? A mixture from which some of the nondissolved particles settle out slowly upon standing. 31. What some examples of suspensions? Chocolate milk Paint Blood

When water breaks apart, what kind of ions are formed? Hydrogen (H+) ions and hydroxide (OH-) ions ( ) + (-) 33. What does the pH scale indicate? It indicates the concentration of hydrogen ions (H+) in a solution.

34. What is the range of the pH scale? 0 to 14 What is the pH of a substance that has an equal number of H+ and OH- ions? 7 Substances with a pH below 7 are ________ while those above 7 are _________? Acids Bases

37. Acids have more ____ions than _____ ions? OH- 38. The _______the pH, the greater the acidity. lower 39. _______ have more OH- ions than H+ ions? Bases

Place the 5 substances listed below on the scale to the right. Oven cleaner Lemon juice Pure water Human blood Soap Lemon juice Oven cleaner Human blood Soap Pure water Click for answer

The pH in most cells in the human body must stay between _______ and______ ? 6.5 7.5 __________ are weak acids or bases that can react with strong acids or bases to stop sharp, sudden changes in pH. Buffers 43. Buffers play an important role in the process of ______________, where living things are able to maintain a stable, internal environment. homeostasis